{"id":100171,"date":"2026-02-15T20:22:14","date_gmt":"2026-02-15T20:22:14","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100171"},"modified":"2026-07-13T00:02:46","modified_gmt":"2026-07-13T00:02:46","slug":"nominal-bore-converter-dn","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/cs\/calculators\/nominal-bore-converter-dn\/","title":{"rendered":"DN \/ NPS \/ OD Cross-Reference Worksheet"},"content":{"rendered":"\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"DN \/ NPS \/ OD Cross-Reference Worksheet\",\"alternateName\":[\"DN NPS Cross-Reference\",\"Pipe OD Worksheet\"],\"description\":\"Reference worksheet that separates the ISO 6708 DN designation, NPS designation, source OD in inches, and the exact mathematical conversion of that OD to millimetres.\",\"url\":\"https:\/\/vibromera.eu\/calculators\/nominal-bore-converter-dn\/\",\"applicationCategory\":\"EngineeringApplication\",\"operatingSystem\":\"Any (Web Browser)\",\"offers\":{\"@type\":\"Offer\",\"price\":\"0\",\"priceCurrency\":\"EUR\"},\"creator\":{\"@type\":\"Organization\",\"name\":\"Vibromera\",\"url\":\"https:\/\/vibromera.eu\/\"},\"datePublished\":\"2024-01-01\",\"dateModified\":\"2026-07-13\",\"inLanguage\":\"en\",\"isAccessibleForFree\":true,\"featureList\":[\"DN 6 to DN 600\",\"NPS 1\/8 to NPS 24\",\"Source OD in inches\",\"Exact inch-to-millimetre calculation\",\"Strict exact-match lookup\"],\"keywords\":\"DN, NPS, nominal diameter, pipe outside diameter, ISO 6708, ASME B36.10\"}\n<\/script>\n\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[\n{\"@type\":\"Question\",\"name\":\"Does ISO 6708 define pipe outside diameters?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No. ISO 6708 defines the DN alphanumeric designation and a preferred series of DN values; DN is dimensionless and does not specify outside diameter, inside diameter, wall thickness or an NPS conversion.\"}},\n{\"@type\":\"Question\",\"name\":\"Is NPS the pipe outside diameter in inches?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Not generally. NPS is a nominal designation. For example, NPS 2 has a source outside diameter of 2.375 inches, while NPS 14 and larger in this worksheet have matching numerical OD values.\"}},\n{\"@type\":\"Question\",\"name\":\"Why are two metric OD values shown?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The public table value follows the displayed metric cross-reference, while the exact mathematical value is source OD in inches multiplied by exactly 25.4 millimetres per inch. Published metric tables may round differently.\"}},\n{\"@type\":\"Question\",\"name\":\"Can this worksheet determine wall thickness or inside diameter?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No. Schedule, material standard and product specification are required. This worksheet intentionally does not calculate wall thickness, inside diameter, pressure rating, tolerance or fitness for service.\"}}\n]}\n<\/script>\n\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"BreadcrumbList\",\"itemListElement\":[\n{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/vibromera.eu\/\"},\n{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Calculators\",\"item\":\"https:\/\/vibromera.eu\/calculators\/\"},\n{\"@type\":\"ListItem\",\"position\":3,\"name\":\"DN \/ NPS \/ OD Cross-Reference Worksheet\",\"item\":\"https:\/\/vibromera.eu\/calculators\/nominal-bore-converter-dn\/\"}\n]}\n<\/script>\n\n<link rel=\"preconnect\" href=\"https:\/\/fonts.googleapis.com\">\n\n<link rel=\"preconnect\" href=\"https:\/\/fonts.gstatic.com\" crossorigin>\n\n<link href=\"https:\/\/fonts.googleapis.com\/css2?family=DM+Sans:ital,opsz,wght@0,9..40,300;0,9..40,400;0,9..40,500;0,9..40,600;0,9..40,700;1,9..40,400&#038;family=JetBrains+Mono:wght@400;500;600&#038;family=Fraunces:opsz,wght@9..144,700;9..144,800&#038;display=swap\" rel=\"stylesheet\">\n\n<style>\n:root {\n    --vc-bg: #f4f1ec;\n    --vc-surface: #ffffff;\n    --vc-surface-alt: #f8f6f2;\n    --vc-ink: #1a1a1a;\n    --vc-ink-secondary: #5a5650;\n    --vc-ink-muted: #8a857e;\n    --vc-accent: #c85a2a;\n    --vc-accent-hover: #b04d22;\n    --vc-accent-light: #fdf0ea;\n    --vc-blue: #2a5c8c;\n    --vc-blue-light: #eaf1f8;\n    --vc-green: #2a7a4b;\n    --vc-green-light: #eaf8ef;\n    --vc-yellow: #a67c00;\n    --vc-yellow-light: #fef9e8;\n    --vc-red: #b91c1c;\n    --vc-red-light: #fef2f2;\n    --vc-border: #d9d4cc;\n    --vc-border-light: #e8e4dd;\n    --vc-shadow: 0 1px 3px rgba(26,26,26,0.06), 0 4px 12px rgba(26,26,26,0.04);\n    --vc-shadow-lg: 0 4px 12px rgba(26,26,26,0.08), 0 16px 40px rgba(26,26,26,0.06);\n    --vc-radius: 8px;\n    --vc-radius-lg: 12px;\n    --vc-font: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;\n    --vc-mono: 'JetBrains Mono', 'Consolas', 'Monaco', monospace;\n    --vc-display: 'Fraunces', Georgia, serif;\n}\n\n.vc-calculator {\n    font-family: var(--vc-font);\n    font-size: 15px;\n    line-height: 1.65;\n    color: var(--vc-ink);\n    max-width: 960px;\n    margin: 0 auto;\n    padding: 20px 16px 40px;\n    -webkit-font-smoothing: antialiased;\n}\n.vc-calculator *, .vc-calculator *::before, .vc-calculator *::after { box-sizing: border-box; }\n\n\/* \u2500\u2500 HEADER \u2500\u2500 *\/\n.vc-header { text-align: center; padding: 48px 24px 40px; position: relative; }\n.vc-header::after { content:''; position:absolute; bottom:0; left:50%; transform:translateX(-50%); width:80px; height:3px; background:var(--vc-accent); border-radius:2px; }\n.vc-header-eyebrow { font-family:var(--vc-mono); font-size:11px; font-weight:500; letter-spacing:0.15em; text-transform:uppercase; color:var(--vc-accent); margin:0 0 12px; }\n.vc-header-title { font-family:var(--vc-display); font-size:clamp(24px,4vw,36px); font-weight:800; line-height:1.15; color:var(--vc-ink); margin:0 0 16px; letter-spacing:-0.02em; }\n.vc-header-subtitle { font-size:15px; color:var(--vc-ink-secondary); margin:0 auto 20px; max-width:600px; }\n.vc-badges { display:inline-flex; gap:8px; flex-wrap:wrap; justify-content:center; }\n.vc-badge { font-family:var(--vc-mono); font-size:11px; font-weight:500; padding:4px 10px; border-radius:4px; background:var(--vc-surface); border:1px solid var(--vc-border); color:var(--vc-ink-secondary); }\n\n\/* \u2500\u2500 CARD \u2500\u2500 *\/\n.vc-card { background:var(--vc-surface); border:1px solid var(--vc-border); border-radius:var(--vc-radius-lg); box-shadow:var(--vc-shadow); overflow:hidden; margin-top:32px; }\n\n\/* \u2500\u2500 FORM \u2500\u2500 *\/\n.vc-form { padding:24px; }\n.vc-form-grid { display:grid; grid-template-columns:1fr 1fr; gap:18px; }\n@media(max-width:600px) { .vc-form-grid { grid-template-columns:1fr; } }\n.vc-field { display:flex; flex-direction:column; }\n.vc-field-full { grid-column: 1 \/ -1; }\n.vc-label { font-size:12px; font-weight:600; letter-spacing:0.04em; text-transform:uppercase; color:var(--vc-ink-secondary); margin-bottom:6px; }\n.vc-label-hint { font-weight:400; text-transform:none; letter-spacing:0; color:var(--vc-ink-muted); font-size:11px; }\n.vc-select, .vc-input { width:100%; padding:10px 12px; border:1.5px solid var(--vc-border); border-radius:6px; font-family:var(--vc-font); font-size:14px; color:var(--vc-ink); background:var(--vc-surface); transition:border-color 0.15s, box-shadow 0.15s; }\n.vc-select { padding-right:36px; appearance:none; -webkit-appearance:none; cursor:pointer; background-image:url(\"data:image\/svg+xml,%3Csvg xmlns='http:\/\/www.w3.org\/2000\/svg' width='16' height='16' fill='none' stroke='%235a5650' stroke-width='2'%3E%3Cpath d='M4 6l4 4 4-4'\/%3E%3C\/svg%3E\"); background-repeat:no-repeat; background-position:right 10px center; }\n.vc-select:focus, .vc-input:focus { outline:none; border-color:var(--vc-accent); box-shadow:0 0 0 3px rgba(200,90,42,0.12); }\n.vc-select:hover, .vc-input:hover { border-color:var(--vc-ink-muted); }\n.vc-validation { min-height:20px; margin-top:6px; color:#a12b2b; font-size:13px; }\n.vc-source-status { margin:0 0 14px; padding:10px 12px; border:1px solid var(--vc-border); border-radius:6px; background:var(--vc-surface-muted); color:var(--vc-ink-secondary); font-size:13px; }\n.vc-source-status code { font-family:var(--vc-mono); font-size:12px; }\n\n\/* \u2500\u2500 PRESETS \u2500\u2500 *\/\n\n\/* \u2500\u2500 RESULTS \u2500\u2500 *\/\n.vc-results { border-top:1px solid var(--vc-border-light); background:var(--vc-surface-alt); padding:0; max-height:0; overflow:hidden; transition:max-height 0.5s cubic-bezier(0.4,0,0.2,1), padding 0.3s; }\n.vc-results.vc-visible { max-height:2000px; padding:24px; }\n.vc-results-head { display:flex; align-items:center; justify-content:space-between; margin-bottom:18px; }\n.vc-results-title { font-family:var(--vc-display); font-size:20px; font-weight:700; color:var(--vc-ink); margin:0; }\n.vc-copy-btn { display:inline-flex; align-items:center; gap:5px; padding:6px 12px; border:1px solid var(--vc-border); border-radius:6px; background:var(--vc-surface); font-family:var(--vc-font); font-size:12px; font-weight:500; color:var(--vc-ink-secondary); cursor:pointer; transition:all 0.15s; }\n.vc-copy-btn:hover { border-color:var(--vc-accent); color:var(--vc-accent); }\n.vc-copy-btn.vc-copied { background:var(--vc-green-light); border-color:var(--vc-green); color:var(--vc-green); }\n\n.vc-result-grid { display:grid; grid-template-columns:1fr 1fr; gap:12px; margin-bottom:20px; }\n@media(max-width:500px) { .vc-result-grid { grid-template-columns:1fr; } }\n.vc-rcard { background:var(--vc-surface); border:1px solid var(--vc-border-light); border-radius:var(--vc-radius); padding:16px; transition:transform 0.2s; }\n.vc-rcard:hover { transform:translateY(-1px); }\n.vc-rcard-primary { border-color:var(--vc-accent); border-width:2px; background:linear-gradient(135deg, #fdf6f2 0%, var(--vc-surface) 100%); grid-column:1 \/ -1; }\n.vc-rcard-label { font-family:var(--vc-mono); font-size:10px; font-weight:500; letter-spacing:0.1em; text-transform:uppercase; color:var(--vc-ink-muted); margin-bottom:4px; }\n.vc-rcard-value { font-family:var(--vc-mono); font-size:22px; font-weight:600; color:var(--vc-ink); line-height:1.2; }\n.vc-rcard-primary .vc-rcard-value { font-size:30px; color:var(--vc-accent); }\n.vc-rcard-unit { font-size:14px; font-weight:400; color:var(--vc-ink-secondary); }\n\n\/* \u2500\u2500 TABLE \u2500\u2500 *\/\n.vc-ref-table-wrap { margin-top:20px; overflow-x:auto; border:1px solid var(--vc-border-light); border-radius:var(--vc-radius); }\n.vc-ref-table { width:100%; border-collapse:collapse; font-size:13px; }\n.vc-ref-table th, .vc-ref-table td { padding:10px 14px; border:1px solid var(--vc-border-light); text-align:center; }\n.vc-ref-table th { background:var(--vc-surface-alt); font-size:11px; font-weight:600; text-transform:uppercase; letter-spacing:0.05em; color:var(--vc-ink-secondary); position:sticky; top:0; z-index:1; }\n.vc-ref-table tr:nth-child(even) { background:var(--vc-surface-alt); }\n.vc-ref-table tr.vc-row-highlight { background:var(--vc-accent-light) !important; }\n.vc-ref-table tr.vc-row-highlight td { color:var(--vc-accent); font-weight:600; }\n@media(max-width:600px) { .vc-ref-table { font-size:12px; } .vc-ref-table th, .vc-ref-table td { padding:8px 6px; } }\n\n\/* \u2500\u2500 COLLAPSIBLE SECTIONS \u2500\u2500 *\/\n.vc-section { margin-top:24px; border:1px solid var(--vc-border); border-radius:var(--vc-radius-lg); background:var(--vc-surface); box-shadow:var(--vc-shadow); overflow:hidden; }\n.vc-section-toggle { width:100%; display:flex; align-items:center; justify-content:space-between; padding:18px 24px; border:none; background:transparent; cursor:pointer; font-family:var(--vc-font); text-align:left; transition:background 0.15s; }\n.vc-section-toggle:hover { background:var(--vc-surface-alt); }\n.vc-section-toggle-text { display:flex; align-items:center; gap:10px; }\n.vc-section-icon { font-size:20px; line-height:1; }\n.vc-section-title { font-family:var(--vc-display); font-size:18px; font-weight:700; color:var(--vc-ink); margin:0; }\n.vc-section-chevron { width:20px; height:20px; color:var(--vc-ink-muted); transition:transform 0.3s; flex-shrink:0; }\n.vc-section.vc-open .vc-section-chevron { transform:rotate(180deg); }\n.vc-section-body { max-height:0; overflow:hidden; transition:max-height 0.4s cubic-bezier(0.4,0,0.2,1); }\n.vc-section.vc-open .vc-section-body { max-height:20000px; }\n.vc-section-inner { padding:0 24px 24px; border-top:1px solid var(--vc-border-light); }\n\n\/* \u2500\u2500 THEORY \u2500\u2500 *\/\n.vc-theory h3 { font-family:var(--vc-display); font-size:17px; font-weight:700; color:var(--vc-ink); margin:28px 0 10px; }\n.vc-theory h3:first-child { margin-top:20px; }\n.vc-theory p { font-size:14px; color:var(--vc-ink-secondary); margin:0 0 10px; }\n.vc-theory ul, .vc-theory ol { font-size:14px; color:var(--vc-ink-secondary); margin:0 0 12px 18px; padding:0; }\n.vc-theory li { margin-bottom:5px; }\n.vc-formula-box { background:var(--vc-surface-alt); border:2px solid var(--vc-border); border-radius:6px; padding:14px 20px; font-family:var(--vc-mono); font-size:16px; font-weight:500; text-align:center; margin:14px 0; color:var(--vc-ink); overflow-x:auto; }\n.vc-info-box { background:var(--vc-blue-light); border-left:3px solid var(--vc-blue); padding:14px 16px; border-radius:0 6px 6px 0; margin:14px 0; }\n.vc-info-box p { margin:0; font-size:14px; color:var(--vc-ink-secondary); }\n.vc-warning-box { background:var(--vc-yellow-light); border-left:3px solid var(--vc-yellow); padding:14px 16px; border-radius:0 6px 6px 0; margin:14px 0; }\n.vc-table { width:100%; border-collapse:collapse; margin:14px 0; font-size:13px; }\n.vc-table th, .vc-table td { padding:10px 12px; border:1px solid var(--vc-border-light); text-align:left; }\n.vc-table th { background:var(--vc-surface-alt); font-size:11px; font-weight:600; text-transform:uppercase; letter-spacing:0.05em; color:var(--vc-ink-secondary); }\n.vc-table tr:nth-child(even) { background:var(--vc-surface-alt); }\n@media(max-width:600px) { .vc-table { font-size:12px; } .vc-table th, .vc-table td { padding:8px; } }\n\n\/* \u2500\u2500 FAQ \u2500\u2500 *\/\n.vc-faq-list { display:flex; flex-direction:column; gap:8px; margin-top:20px; }\n.vc-faq-item { border:1px solid var(--vc-border-light); border-radius:6px; overflow:hidden; }\n.vc-faq-q { width:100%; display:flex; align-items:center; justify-content:space-between; gap:12px; padding:14px 16px; border:none; background:var(--vc-surface-alt); cursor:pointer; font-family:var(--vc-font); font-size:15px; font-weight:600; color:var(--vc-ink); text-align:left; transition:background 0.15s; }\n.vc-faq-q:hover { background:#ede9e3; }\n.vc-faq-chevron { width:16px; height:16px; color:var(--vc-ink-muted); flex-shrink:0; transition:transform 0.25s; }\n.vc-faq-item.vc-open .vc-faq-chevron { transform:rotate(180deg); }\n.vc-faq-a { max-height:0; overflow:hidden; transition:max-height 0.35s; }\n.vc-faq-item.vc-open .vc-faq-a { max-height:1200px; }\n.vc-faq-a-inner { padding:14px 16px; border-top:1px solid var(--vc-border-light); font-size:14px; color:var(--vc-ink-secondary); }\n.vc-faq-a-inner p { margin:0 0 8px; }\n.vc-faq-a-inner p:last-child { margin-bottom:0; }\n.vc-faq-a-inner ul { margin:4px 0 8px 16px; padding:0; }\n.vc-faq-a-inner li { margin-bottom:3px; }\n\n\/* \u2500\u2500 RELATED \u2500\u2500 *\/\n.vc-related { display:flex; flex-wrap:wrap; gap:10px; margin-top:16px; }\n.vc-related-link { display:inline-block; padding:8px 16px; font-family:var(--vc-font); font-size:13px; font-weight:600; background:var(--vc-surface-alt); color:var(--vc-ink-secondary); border:1px solid var(--vc-border); border-radius:var(--vc-radius); text-decoration:none; transition:all 0.15s; }\n.vc-related-link:hover { border-color:var(--vc-accent); color:var(--vc-accent); background:var(--vc-accent-light); }\n\n\/* \u2500\u2500 PROMO \u2500\u2500 *\/\n.vc-promo { margin-top:24px; padding:20px; background:linear-gradient(135deg, var(--vc-accent-light), var(--vc-surface)); border:1px solid var(--vc-border); border-radius:var(--vc-radius-lg); display:flex; align-items:center; gap:16px; }\n.vc-promo-text { flex:1; font-size:14px; color:var(--vc-ink-secondary); }\n.vc-promo-text strong { color:var(--vc-ink); }\n.vc-promo-link { padding:8px 20px; font-size:13px; font-weight:700; color:#fff; background:var(--vc-accent); border-radius:var(--vc-radius); text-decoration:none; white-space:nowrap; transition:background 0.15s; }\n.vc-promo-link:hover { background:var(--vc-accent-hover); }\n\n\/* \u2500\u2500 FOOTER \u2500\u2500 *\/\n.vc-footer { text-align:center; padding:32px 16px; font-size:13px; color:var(--vc-ink-muted); }\n.vc-footer a { color:var(--vc-accent); text-decoration:none; }\n.vc-footer a:hover { text-decoration:underline; }\n.vc-footer-links { margin-top:8px; font-size:12px; }\n.vc-footer-links a { margin:0 8px; }\n\n\/* \u2500\u2500 PRINT \u2500\u2500 *\/\n@media print {\n    .vc-section-body { max-height:none!important; }\n    .vc-faq-a { max-height:none!important; }\n    .vc-results { max-height:none!important; padding:24px!important; }\n    .vc-copy-btn, .vc-section-chevron, .vc-faq-chevron, .vc-promo { display:none!important; }\n}\n<\/style>\n\n<div class=\"vc-calculator\" id=\"vc-nominal-bore\">\n\n<!-- Header -->\n<header class=\"vc-header\">\n    <p class=\"vc-header-eyebrow\">Engineering reference worksheet<\/p>\n    <h1 class=\"vc-header-title\">DN \/ NPS \/ OD Cross-Reference<\/h1>\n    <p class=\"vc-header-subtitle\">Look up a publicly corroborated DN\u2013NPS pairing and pipe outside diameter. DN, NPS and measured diameter are kept separate.<\/p>\n    <div class=\"vc-badges\">\n        <span class=\"vc-badge\">ISO 6708:1995 \u2014 DN only<\/span>\n        <span class=\"vc-badge\">Public table corroboration<\/span>\n        <span class=\"vc-badge\">NPS 1\/8 \u2013 24<\/span>\n    <\/div>\n<\/header>\n\n<!-- Calculator Card -->\n<div class=\"vc-card\">\n    <form class=\"vc-form\" id=\"vc-form\" autocomplete=\"off\">\n        <div class=\"vc-source-status\"><strong>Evidence status:<\/strong> <code>PUBLICLY_CORROBORATED<\/code>. Direct verification of every row against licensed ASME B36.10-2022 Table 2-1: <code>NEEDS_LICENSED_SOURCE<\/code>.<\/div>\n        <div class=\"vc-form-grid\">\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-basis\">Lookup basis<\/label>\n                <select class=\"vc-select\" id=\"vc-basis\">\n                    <option value=\"dn\">DN designation<\/option>\n                    <option value=\"nps\">NPS designation<\/option>\n                    <option value=\"od_in\">Source OD (in)<\/option>\n                    <option value=\"od_mm\">OD (mm)<\/option>\n                <\/select>\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-value\">Exact value <span class=\"vc-label-hint\" id=\"vc-value-hint\">(for example DN 50)<\/span><\/label>\n                <input class=\"vc-input\" type=\"text\" id=\"vc-value\" inputmode=\"decimal\" aria-describedby=\"vc-validation\" placeholder=\"DN 50\">\n                <div class=\"vc-validation\" id=\"vc-validation\" role=\"status\" aria-live=\"polite\"><\/div>\n            <\/div>\n        <\/div>\n    <\/form>\n\n    <!-- Results -->\n    <div class=\"vc-results\" id=\"vc-results\">\n        <div class=\"vc-results-head\">\n            <h2 class=\"vc-results-title\">Results<\/h2>\n            <button type=\"button\" class=\"vc-copy-btn\" id=\"vc-copy-btn\">\n                <svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><rect x=\"9\" y=\"9\" width=\"13\" height=\"13\" rx=\"2\"\/><path d=\"M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1\"\/><\/svg>\n                Copy\n            <\/button>\n        <\/div>\n        <div class=\"vc-result-grid\">\n            <div class=\"vc-rcard vc-rcard-primary\">\n                <div class=\"vc-rcard-label\">Source OD<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-od\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">DN (Nominal Diameter)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-dn\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">NPS (Nominal Pipe Size)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-nps\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Public table OD<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-public-mm\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Exact conversion<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-exact-mm\">\u2014<\/div>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- Full Reference Table -->\n<div class=\"vc-section vc-open\" id=\"vc-sec-table\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"true\">\n        <span class=\"vc-section-toggle-text\">\n            <span class=\"vc-section-icon\">\ud83d\udccb<\/span>\n            <span class=\"vc-section-title\">Full Reference Table<\/span>\n        <\/span>\n        <svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner\">\n            <div class=\"vc-ref-table-wrap\">\n                <table class=\"vc-ref-table\" id=\"vc-ref-table\">\n                    <thead>\n                        <tr>\n                            <th>DN<\/th>\n                            <th>NPS<\/th>\n                            <th>Source OD (in)<\/th>\n                            <th>Public table OD (mm)<\/th>\n                            <th>Exact OD \u00d7 25.4 (mm)<\/th>\n                        <\/tr>\n                    <\/thead>\n                    <tbody id=\"vc-table-body\"><\/tbody>\n                <\/table>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- Theory & Reference -->\n<div class=\"vc-section\" id=\"vc-sec-theory\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\">\n        <span class=\"vc-section-toggle-text\">\n            <span class=\"vc-section-icon\">\ud83d\udcd8<\/span>\n            <span class=\"vc-section-title\">Theory &amp; Reference<\/span>\n        <\/span>\n        <svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner vc-theory\">\n            <h3>What ISO 6708 does\u2014and does not\u2014define<\/h3>\n            <p>ISO 6708:1995 defines DN as an alphanumeric designation for reference purposes. It consists of the letters DN followed by a dimensionless whole number indirectly related to physical size. The standard supplies a preferred DN series; it does not itself define NPS, outside diameter, inside diameter or wall thickness.<\/p>\n\n            <h3>What this worksheet reports<\/h3>\n            <p>Each row contains four distinct data items: a DN designation, an NPS designation, a source outside diameter in inches, and a publicly displayed metric OD. The calculated value uses only the exact unit identity:<\/p>\n            <div class=\"vc-formula-box\">exact OD (mm) = source OD (in) \u00d7 25.4 mm\/in<\/div>\n            <p>Because published tables round metric displays, the public metric value can differ slightly from the exact conversion. For example, 10.750 in \u00d7 25.4 = 273.05 mm, while the public table display is commonly 273.0 mm.<\/p>\n\n            <div class=\"vc-info-box\">\n                <p><strong>Corrected size:<\/strong> NPS 5 has a source OD of 5.563 in and public metric OD of 141.3 mm. A separate 5.500 in \/ DN125 product size also appears in current manufacturer literature; it must not be substituted for NPS 5.<\/p>\n            <\/div>\n\n            <h3>Scope and limitations<\/h3>\n            <p>This is an exact-match cross-reference, not a dimensional design calculator. It does not infer a nearest size and does not provide schedule, wall thickness, inside diameter, tolerance, mass, pressure rating, material compatibility or fitness for service. Those require the applicable product\/material standard and project specification.<\/p>\n\n            <div class=\"vc-warning-box\">\n                <p style=\"margin:0;font-size:14px;color:var(--vc-ink-secondary);\"><strong>Source limitation:<\/strong> ISO 6708:1995 is verified for the meaning and preferred series of DN. The DN\/NPS\/OD rows are corroborated against current publicly available manufacturer tables. Direct row-by-row verification against licensed ASME B36.10-2022 Table 2-1 and separate applicability checks for ASME B36.19-2022 remain <strong>NEEDS_LICENSED_SOURCE<\/strong>.<\/p>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- Related Calculators -->\n<div class=\"vc-section\" id=\"vc-sec-related\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\">\n        <span class=\"vc-section-toggle-text\">\n            <span class=\"vc-section-icon\">\ud83d\udd17<\/span>\n            <span class=\"vc-section-title\">Related Calculators<\/span>\n        <\/span>\n        <svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner\">\n            <div class=\"vc-related\">\n                <a class=\"vc-related-link\" href=\"\/calculators\/pipe-flow-velocity\/\">Pipe Flow Velocity<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/flange-bolt-calculator\/\">Flange Bolt Torque<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/pipe-pressure-drop\/\">Pressure Drop (Darcy-Weisbach)<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/affinity-laws-calculator\/\">Affinity Laws Calculator<\/a>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- FAQ -->\n<div class=\"vc-section\" id=\"vc-sec-faq\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\">\n        <span class=\"vc-section-toggle-text\">\n            <span class=\"vc-section-icon\">\u2753<\/span>\n            <span class=\"vc-section-title\">Frequently Asked Questions<\/span>\n        <\/span>\n        <svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner\">\n            <div class=\"vc-faq-list\" id=\"vc-faq-list\"><\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- Promo -->\n<div class=\"vc-promo\">\n    <div class=\"vc-promo-text\">\n        <strong>Vibromera \u2014 Portable Balancing &amp; Vibration Analysis<\/strong><br>\n        Professional field balancing instruments and software. Used in 50+ countries worldwide.\n    <\/div>\n    <a class=\"vc-promo-link\" href=\"https:\/\/vibromera.eu\/\" target=\"_blank\" rel=\"noopener\">Learn More<\/a>\n<\/div>\n\n<!-- Footer -->\n<footer class=\"vc-footer\">\n    <p>\u00a9 2024\u20132026 <a href=\"https:\/\/vibromera.eu\/\">Vibromera<\/a> \u2014 Engineering Calculators<\/p>\n    <p style=\"font-size:12px;margin-top:4px;\">DN definition: ISO 6708:1995. Public cross-reference reviewed 13 July 2026; licensed ASME table verification remains pending.<\/p>\n    <div class=\"vc-footer-links\">\n        <a href=\"\/calculators\/engineering-calculators\/\">All 252 Calculators<\/a>\n        <a href=\"https:\/\/vibromera.eu\/contacts\/\">Contact<\/a>\n    <\/div>\n<\/footer>\n\n<\/div>\n\n<script>\n(function() {\n    'use strict';\n\n    \/* Publicly corroborated cross-reference. Direct row-by-row verification\n       against licensed ASME B36.10-2022 Table 2-1 remains NEEDS_LICENSED_SOURCE. *\/\n    var DATA = [\n        { dn:6,   nps:'1\/8',   nps_value:0.125, od_in:0.405,  od_in_text:'0.405',  od_mm:10.3 },\n        { dn:8,   nps:'1\/4',   nps_value:0.25,  od_in:0.540,  od_in_text:'0.540',  od_mm:13.7 },\n        { dn:10,  nps:'3\/8',   nps_value:0.375, od_in:0.675,  od_in_text:'0.675',  od_mm:17.1 },\n        { dn:15,  nps:'1\/2',   nps_value:0.5,   od_in:0.840,  od_in_text:'0.840',  od_mm:21.3 },\n        { dn:20,  nps:'3\/4',   nps_value:0.75,  od_in:1.050,  od_in_text:'1.050',  od_mm:26.7 },\n        { dn:25,  nps:'1',     nps_value:1,     od_in:1.315,  od_in_text:'1.315',  od_mm:33.4 },\n        { dn:32,  nps:'1-1\/4', nps_value:1.25,  od_in:1.660,  od_in_text:'1.660',  od_mm:42.2 },\n        { dn:40,  nps:'1-1\/2', nps_value:1.5,   od_in:1.900,  od_in_text:'1.900',  od_mm:48.3 },\n        { dn:50,  nps:'2',     nps_value:2,     od_in:2.375,  od_in_text:'2.375',  od_mm:60.3 },\n        { dn:65,  nps:'2-1\/2', nps_value:2.5,   od_in:2.875,  od_in_text:'2.875',  od_mm:73.0 },\n        { dn:80,  nps:'3',     nps_value:3,     od_in:3.500,  od_in_text:'3.500',  od_mm:88.9 },\n        { dn:90,  nps:'3-1\/2', nps_value:3.5,   od_in:4.000,  od_in_text:'4.000',  od_mm:101.6 },\n        { dn:100, nps:'4',     nps_value:4,     od_in:4.500,  od_in_text:'4.500',  od_mm:114.3 },\n        { dn:125, nps:'5',     nps_value:5,     od_in:5.563,  od_in_text:'5.563',  od_mm:141.3 },\n        { dn:150, nps:'6',     nps_value:6,     od_in:6.625,  od_in_text:'6.625',  od_mm:168.3 },\n        { dn:200, nps:'8',     nps_value:8,     od_in:8.625,  od_in_text:'8.625',  od_mm:219.1 },\n        { dn:250, nps:'10',    nps_value:10,    od_in:10.750, od_in_text:'10.750', od_mm:273.0 },\n        { dn:300, nps:'12',    nps_value:12,    od_in:12.750, od_in_text:'12.750', od_mm:323.9 },\n        { dn:350, nps:'14',    nps_value:14,    od_in:14.000, od_in_text:'14.000', od_mm:355.6 },\n        { dn:400, nps:'16',    nps_value:16,    od_in:16.000, od_in_text:'16.000', od_mm:406.4 },\n        { dn:450, nps:'18',    nps_value:18,    od_in:18.000, od_in_text:'18.000', od_mm:457.2 },\n        { dn:500, nps:'20',    nps_value:20,    od_in:20.000, od_in_text:'20.000', od_mm:508.0 },\n        { dn:550, nps:'22',    nps_value:22,    od_in:22.000, od_in_text:'22.000', od_mm:558.8 },\n        { dn:600, nps:'24',    nps_value:24,    od_in:24.000, od_in_text:'24.000', od_mm:609.6 }\n    ];\n\n    function $(id) { return document.getElementById(id); }\n    function closeEnough(a, b) { return Math.abs(a - b) < 1e-9; }\n    function fmtExact(n) {\n        return n.toFixed(4).replace(\/(\\.\\d*?)0+$\/, '$1').replace(\/\\.$\/, '');\n    }\n    function clearNode(node) {\n        while (node.firstChild) node.removeChild(node.firstChild);\n    }\n    function addCell(row, text) {\n        var cell = document.createElement('td');\n        cell.textContent = text;\n        row.appendChild(cell);\n    }\n    function parsePositiveNumber(raw, suffixPattern) {\n        var value = String(raw || '').trim().toLowerCase();\n        if (suffixPattern) value = value.replace(suffixPattern, '').trim();\n        if (!value || (value.indexOf(',') !== -1 && value.indexOf('.') !== -1)) return null;\n        value = value.replace(',', '.');\n        if (!\/^(?:\\d+(?:\\.\\d*)?|\\.\\d+)$\/.test(value)) return null;\n        var number = Number(value);\n        return Number.isFinite(number) && number > 0 ? number : null;\n    }\n    function parseDN(raw) {\n        var match = String(raw || '').trim().match(\/^(?:dn\\s*)?(\\d+)$\/i);\n        return match ? Number(match[1]) : null;\n    }\n    function parseNPS(raw) {\n        var value = String(raw || '').trim().toLowerCase()\n            .replace(\/^nps\\s*\/, '').replace(\/(?:\\s*(?:in|inch|inches)|\\s*\")$\/, '').trim();\n        var mixed = value.match(\/^(\\d+)[-\\s]+(\\d+)\\s*\\\/\\s*(\\d+)$\/);\n        var fraction = value.match(\/^(\\d+)\\s*\\\/\\s*(\\d+)$\/);\n        var result;\n        if (mixed) {\n            if (Number(mixed[3]) === 0) return null;\n            result = Number(mixed[1]) + Number(mixed[2]) \/ Number(mixed[3]);\n        } else if (fraction) {\n            if (Number(fraction[2]) === 0) return null;\n            result = Number(fraction[1]) \/ Number(fraction[2]);\n        } else {\n            result = parsePositiveNumber(value);\n        }\n        return Number.isFinite(result) && result > 0 ? result : null;\n    }\n    function findEntry(basis, raw) {\n        var value;\n        if (basis === 'dn') value = parseDN(raw);\n        if (basis === 'nps') value = parseNPS(raw);\n        if (basis === 'od_in') value = parsePositiveNumber(raw, \/(?:\\s*(?:in|inch|inches)|\\s*\")$\/i);\n        if (basis === 'od_mm') value = parsePositiveNumber(raw, \/\\s*mm$\/i);\n        if (value === null || value === undefined) return { entry:null, invalid:true };\n        for (var i = 0; i < DATA.length; i++) {\n            var item = DATA[i];\n            if (basis === 'dn' && item.dn === value) return { entry:item, invalid:false };\n            if (basis === 'nps' && closeEnough(item.nps_value, value)) return { entry:item, invalid:false };\n            if (basis === 'od_in' && closeEnough(item.od_in, value)) return { entry:item, invalid:false };\n            if (basis === 'od_mm' && (closeEnough(item.od_mm, value) || closeEnough(item.od_in * 25.4, value))) return { entry:item, invalid:false };\n        }\n        return { entry:null, invalid:false };\n    }\n\n    var selectedDN = null;\n    function buildTable() {\n        var body = $('vc-table-body');\n        clearNode(body);\n        DATA.forEach(function(item) {\n            var row = document.createElement('tr');\n            row.setAttribute('data-dn', String(item.dn));\n            if (item.dn === selectedDN) row.classList.add('vc-row-highlight');\n            addCell(row, 'DN ' + item.dn);\n            addCell(row, 'NPS ' + item.nps);\n            addCell(row, item.od_in_text + ' in');\n            addCell(row, item.od_mm.toFixed(1) + ' mm');\n            addCell(row, fmtExact(item.od_in * 25.4) + ' mm');\n            body.appendChild(row);\n        });\n    }\n    function hideResult() {\n        selectedDN = null;\n        $('vc-results').classList.remove('vc-visible');\n        buildTable();\n    }\n    function showResult(item) {\n        selectedDN = item.dn;\n        $('vc-r-od').textContent = item.od_in_text + ' in';\n        $('vc-r-dn').textContent = 'DN ' + item.dn;\n        $('vc-r-nps').textContent = 'NPS ' + item.nps;\n        $('vc-r-public-mm').textContent = item.od_mm.toFixed(1) + ' mm';\n        $('vc-r-exact-mm').textContent = fmtExact(item.od_in * 25.4) + ' mm';\n        $('vc-results').classList.add('vc-visible');\n        buildTable();\n    }\n    function runLookup() {\n        var raw = $('vc-value').value;\n        if (!raw.trim()) {\n            $('vc-validation').textContent = '';\n            hideResult();\n            return;\n        }\n        var result = findEntry($('vc-basis').value, raw);\n        if (result.invalid) {\n            $('vc-validation').textContent = 'Enter one positive value in the selected format.';\n            hideResult();\n            return;\n        }\n        if (!result.entry) {\n            $('vc-validation').textContent = 'No exact controlled-table match. A nearest size is not inferred.';\n            hideResult();\n            return;\n        }\n        $('vc-validation').textContent = '';\n        showResult(result.entry);\n    }\n    var fieldGuide = {\n        dn: { hint:'(for example DN 50)', placeholder:'DN 50' },\n        nps: { hint:'(for example NPS 2 or 1 1\/4)', placeholder:'NPS 2' },\n        od_in: { hint:'(for example 2.375 in)', placeholder:'2.375 in' },\n        od_mm: { hint:'(public display or exact value; comma accepted)', placeholder:'60.3 mm' }\n    };\n    $('vc-basis').addEventListener('change', function() {\n        var guide = fieldGuide[this.value];\n        $('vc-value-hint').textContent = guide.hint;\n        $('vc-value').placeholder = guide.placeholder;\n        $('vc-value').value = '';\n        $('vc-validation').textContent = '';\n        hideResult();\n    });\n    $('vc-value').addEventListener('input', runLookup);\n\n    $('vc-copy-btn').addEventListener('click', function() {\n        var text = 'DN \/ NPS \/ OD cross-reference\\n' +\n            $('vc-r-dn').textContent + '\\n' + $('vc-r-nps').textContent + '\\n' +\n            'Source OD: ' + $('vc-r-od').textContent + '\\n' +\n            'Public table OD: ' + $('vc-r-public-mm').textContent + '\\n' +\n            'Exact OD \u00d7 25.4: ' + $('vc-r-exact-mm').textContent + '\\n' +\n            'Evidence: PUBLICLY_CORROBORATED; licensed ASME table verification pending.\\n' +\n            'vibromera.eu\/calculators\/nominal-bore-converter-dn\/';\n        if (navigator.clipboard) {\n            navigator.clipboard.writeText(text).then(function() {\n                var button = $('vc-copy-btn');\n                button.classList.add('vc-copied');\n                button.textContent = 'Copied!';\n                setTimeout(function() {\n                    button.classList.remove('vc-copied');\n                    button.textContent = 'Copy';\n                }, 2000);\n            });\n        }\n    });\n\n    document.querySelectorAll('.vc-section-toggle').forEach(function(button) {\n        button.addEventListener('click', function() {\n            var section = this.closest('.vc-section');\n            var wasOpen = section.classList.contains('vc-open');\n            section.classList.toggle('vc-open');\n            this.setAttribute('aria-expanded', String(!wasOpen));\n        });\n    });\n\n    var faqData = [\n        ['Does ISO 6708 define pipe outside diameters?', ['No. ISO 6708:1995 defines the DN designation and preferred DN values. It does not define an outside diameter, inside diameter, wall thickness or NPS conversion.']],\n        ['Is NPS the outside diameter in inches?', ['Not generally. NPS is nominal. NPS 2 in this cross-reference has a source OD of 2.375 in.']],\n        ['Why are two metric OD values shown?', ['The public metric value reproduces the rounded display in the corroborating tables. The exact value is independently calculated from the source inch OD using 1 in = exactly 25.4 mm.']],\n        ['Can I use this result to select a schedule or pressure rating?', ['No. Schedule, wall thickness, material, tolerance and pressure design are outside this worksheet. Use the applicable licensed product and design standards.']]\n    ];\n    var faqList = $('vc-faq-list');\n    faqData.forEach(function(item) {\n        var wrapper = document.createElement('div');\n        wrapper.className = 'vc-faq-item';\n        var button = document.createElement('button');\n        button.type = 'button';\n        button.className = 'vc-faq-q';\n        var title = document.createElement('span');\n        title.textContent = item[0];\n        button.appendChild(title);\n        var answer = document.createElement('div');\n        answer.className = 'vc-faq-a';\n        var inner = document.createElement('div');\n        inner.className = 'vc-faq-a-inner';\n        item[1].forEach(function(text) {\n            var paragraph = document.createElement('p');\n            paragraph.textContent = text;\n            inner.appendChild(paragraph);\n        });\n        answer.appendChild(inner);\n        wrapper.appendChild(button);\n        wrapper.appendChild(answer);\n        faqList.appendChild(wrapper);\n    });\n    faqList.addEventListener('click', function(event) {\n        var button = event.target.closest('.vc-faq-q');\n        if (button) button.closest('.vc-faq-item').classList.toggle('vc-open');\n    });\n\n    function init() { buildTable(); }\n    if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', init);\n    else init();\n})();\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>Exact-match DN and NPS cross-reference with source pipe OD in inches, public metric display, and the exact \u00d725.4 conversion. ISO 6708 defines DN only; licensed ASME table verification remains pending.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-100171","calculator","type-calculator","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/cs\/wp-json\/wp\/v2\/calculator\/100171","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/cs\/wp-json\/wp\/v2\/calculator"}],"about":[{"href":"https:\/\/vibromera.eu\/cs\/wp-json\/wp\/v2\/types\/calculator"}],"version-history":[{"count":2,"href":"https:\/\/vibromera.eu\/cs\/wp-json\/wp\/v2\/calculator\/100171\/revisions"}],"predecessor-version":[{"id":102508,"href":"https:\/\/vibromera.eu\/cs\/wp-json\/wp\/v2\/calculator\/100171\/revisions\/102508"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/cs\/wp-json\/wp\/v2\/media?parent=100171"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/cs\/wp-json\/wp\/v2\/categories?post=100171"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/cs\/wp-json\/wp\/v2\/tags?post=100171"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}