{"id":100252,"date":"2026-02-15T20:29:46","date_gmt":"2026-02-15T20:29:46","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100252"},"modified":"2026-02-15T20:29:46","modified_gmt":"2026-02-15T20:29:46","slug":"surface-roughness-converter","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/nb\/calculators\/surface-roughness-converter\/","title":{"rendered":"Overflateruhetsomformer | Ra \u2194 Rz \u2194 Klasse \u2194 Finish"},"content":{"rendered":"\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"Surface Roughness Converter\",\"alternateName\":[\"Ra Rz Converter\",\"Roughness Class Calculator\",\"Surface Finish Calculator\"],\"description\":\"Free online surface roughness converter. Convert between Ra, Rz, roughness class (N1\u2013N12), and CLA\/AA microinch values. Includes typical machining processes and surface finish descriptions.\",\"url\":\"https:\/\/vibromera.eu\/calculators\/surface-roughness-converter\/\",\"applicationCategory\":\"Engineering Calculator\",\"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\":\"2025-02-14\",\"inLanguage\":\"en\",\"isAccessibleForFree\":true,\"featureList\":[\"Ra to Rz conversion\",\"Roughness class N1\u2013N12\",\"CLA\/AA microinch conversion\",\"Typical process identification\",\"Auto-calculation on input change\",\"Full reference table\"],\"keywords\":\"surface roughness, Ra, Rz, roughness class, CLA, microinch, surface finish\"}\n<\/script>\n\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[\n{\"@type\":\"Question\",\"name\":\"What is the difference between Ra and Rz?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Ra (arithmetical mean roughness) is the average of absolute profile deviations from the mean line over the evaluation length. Rz (maximum height) is the average of the five highest peaks and five deepest valleys within the evaluation length. Ra gives an overall average roughness, while Rz is more sensitive to individual peaks and valleys. Roughly, Rz \u2248 4\u00d7Ra for most machined surfaces.\"}},\n{\"@type\":\"Question\",\"name\":\"How do I convert between Ra and Rz?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"A rough approximation is Rz \u2248 4\u00d7Ra, but the exact ratio depends on the surface profile and machining process. For precision work, use the ISO standard conversion tables. For general engineering, the \u00d74 factor provides a reasonable estimate.\"}},\n{\"@type\":\"Question\",\"name\":\"What is N class (roughness grade)?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"N classes (N1 through N12) are roughness grade numbers defined in ISO 1302. Each grade corresponds to a specific Ra value: N1=0.025 \u03bcm, N2=0.05 \u03bcm, N3=0.1 \u03bcm, up to N12=50 \u03bcm. They provide a simplified way to specify surface roughness on drawings.\"}},\n{\"@type\":\"Question\",\"name\":\"What is typical Ra for machining operations?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Typical Ra values: Lapping\/superfinishing: 0.025\u20130.1 \u03bcm (N1\u2013N3). Fine grinding: 0.2\u20130.4 \u03bcm (N4\u2013N5). Normal grinding\/fine turning: 0.8\u20131.6 \u03bcm (N6\u2013N7). Rough turning\/milling: 3.2\u201312.5 \u03bcm (N8\u2013N10). Casting\/forging: 25\u201350 \u03bcm (N11\u2013N12).\"}},\n{\"@type\":\"Question\",\"name\":\"What Ra is needed for bearing seats?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Bearing seats typically require Ra 0.8\u20131.6 \u03bcm (N6\u2013N7) for the shaft and housing bore. For precision bearings, Ra 0.4 \u03bcm (N5) or better may be needed. Always check the bearing manufacturer's recommendations.\"}}\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\":\"Surface Roughness Converter\",\"item\":\"https:\/\/vibromera.eu\/calculators\/surface-roughness-converter\/\"}\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<link rel=\"stylesheet\" href=\"https:\/\/cdn.jsdelivr.net\/npm\/katex@0.16.11\/dist\/katex.min.css\">\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; 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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); 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}\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; 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}\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.vc-table tr.vc-row-highlight td { background:var(--vc-accent-light); }\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; 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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 TABLE SCROLL \u2500\u2500 *\/\n.vc-table-wrap { overflow-x:auto; margin:14px 0; }\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-presets, .vc-promo { display:none!important; }\n}\n<\/style>\n\n<div class=\"vc-calculator\" id=\"vc-surface-roughness\">\n\n<!-- Header -->\n<header class=\"vc-header\">\n    <p class=\"vc-header-eyebrow\">Free Engineering Tool<\/p>\n    <h1 class=\"vc-header-title\">Surface Roughness Converter<\/h1>\n    <p class=\"vc-header-subtitle\">Convert between Ra, Rz, roughness class (N1\u2013N12), and CLA\/AA microinch values. Includes surface finish descriptions and typical machining processes.<\/p>\n    <div class=\"vc-badges\">\n        <span class=\"vc-badge\">Ra \u2194 Rz<\/span>\n        <span class=\"vc-badge\">Class N1\u2013N12<\/span>\n        <span class=\"vc-badge\">CLA \/ AA \u03bcin<\/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-form-grid\">\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-type\">Input Type<\/label>\n                <select class=\"vc-select\" id=\"vc-type\">\n                    <option value=\"ra\" selected>Ra (\u03bcm)<\/option>\n                    <option value=\"rz\">Rz (\u03bcm)<\/option>\n                    <option value=\"class\">Class N (N1\u2013N12)<\/option>\n                    <option value=\"cla\">CLA \/ AA (\u03bcin)<\/option>\n                <\/select>\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-val\">Value <span class=\"vc-label-hint\" id=\"vc-val-hint\">(\u03bcm)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-val\" inputmode=\"decimal\" step=\"any\" min=\"0\" placeholder=\"e.g. 1.6\" value=\"1.6\">\n            <\/div>\n        <\/div>\n\n        <!-- Presets -->\n        <div class=\"vc-presets\">\n            <div class=\"vc-presets-label\">Quick presets<\/div>\n            <button type=\"button\" class=\"vc-preset-btn\" data-t=\"ra\" data-v=\"1.6\">Ra 1.6 \u03bcm<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-t=\"rz\" data-v=\"6.3\">Rz 6.3 \u03bcm<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-t=\"class\" data-v=\"8\">Class N8<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-t=\"cla\" data-v=\"32\">32 \u03bcin CLA<\/button>\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\">Ra (Arithmetical Mean Roughness)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-ra\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Rz (Maximum Height)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-rz\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Roughness Class<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-class\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">CLA \/ AA<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-cla\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Surface Description<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-desc\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Typical Process<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-process\">\u2014<\/div>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- 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\udcca<\/span>\n            <span class=\"vc-section-title\">Full Conversion 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 vc-theory\">\n            <div class=\"vc-table-wrap\">\n                <table class=\"vc-table\" id=\"vc-ref-table\">\n                    <thead>\n                        <tr>\n                            <th>Class<\/th>\n                            <th>Ra (\u03bcm)<\/th>\n                            <th>Rz (\u03bcm)<\/th>\n                            <th>CLA (\u03bcin)<\/th>\n                            <th>Description<\/th>\n                            <th>Typical Process<\/th>\n                        <\/tr>\n                    <\/thead>\n                    <tbody>\n                        <tr data-n=\"1\"><td>N1<\/td><td>0.025<\/td><td>0.1<\/td><td>1<\/td><td>Mirror finish<\/td><td>Superfinishing, lapping<\/td><\/tr>\n                        <tr data-n=\"2\"><td>N2<\/td><td>0.05<\/td><td>0.2<\/td><td>2<\/td><td>Mirror finish<\/td><td>Superfinishing, lapping<\/td><\/tr>\n                        <tr data-n=\"3\"><td>N3<\/td><td>0.1<\/td><td>0.4<\/td><td>4<\/td><td>Very smooth<\/td><td>Lapping, honing<\/td><\/tr>\n                        <tr data-n=\"4\"><td>N4<\/td><td>0.2<\/td><td>0.8<\/td><td>8<\/td><td>Smooth<\/td><td>Fine grinding, honing<\/td><\/tr>\n                        <tr data-n=\"5\"><td>N5<\/td><td>0.4<\/td><td>1.6<\/td><td>16<\/td><td>Smooth<\/td><td>Fine grinding<\/td><\/tr>\n                        <tr data-n=\"6\"><td>N6<\/td><td>0.8<\/td><td>3.2<\/td><td>32<\/td><td>Fine<\/td><td>Grinding, fine turning<\/td><\/tr>\n                        <tr data-n=\"7\"><td>N7<\/td><td>1.6<\/td><td>6.3<\/td><td>63<\/td><td>Fine<\/td><td>Turning, milling<\/td><\/tr>\n                        <tr data-n=\"8\"><td>N8<\/td><td>3.2<\/td><td>12.5<\/td><td>125<\/td><td>Medium<\/td><td>Turning, milling<\/td><\/tr>\n                        <tr data-n=\"9\"><td>N9<\/td><td>6.3<\/td><td>25<\/td><td>250<\/td><td>Medium rough<\/td><td>Rough machining<\/td><\/tr>\n                        <tr data-n=\"10\"><td>N10<\/td><td>12.5<\/td><td>50<\/td><td>500<\/td><td>Rough<\/td><td>Rough machining<\/td><\/tr>\n                        <tr data-n=\"11\"><td>N11<\/td><td>25<\/td><td>100<\/td><td>1000<\/td><td>Very rough<\/td><td>Casting, forging<\/td><\/tr>\n                        <tr data-n=\"12\"><td>N12<\/td><td>50<\/td><td>200<\/td><td>2000<\/td><td>Very rough<\/td><td>Casting, forging, flame cut<\/td><\/tr>\n                    <\/tbody>\n                <\/table>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- Theory & Formulas -->\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; Formulas<\/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>Ra \u2014 Arithmetical Mean Roughness<\/h3>\n            <p>Ra is the arithmetical average of the absolute values of the profile deviations from the mean line, measured over the evaluation length:<\/p>\n            <div class=\"vc-formula-box\" id=\"vc-katex-1\"><\/div>\n            <p>Ra is the most commonly used roughness parameter worldwide. It gives a general indication of surface texture but can mask individual peaks or valleys.<\/p>\n\n            <h3>Rz \u2014 Maximum Height of Profile<\/h3>\n            <p>Rz is the average of the single roughness depths of five consecutive sampling lengths. It is more sensitive to outlier peaks and valleys:<\/p>\n            <div class=\"vc-formula-box\" id=\"vc-katex-2\"><\/div>\n\n            <h3>Approximate Conversion<\/h3>\n            <div class=\"vc-formula-box\" id=\"vc-katex-3\"><\/div>\n            <div class=\"vc-info-box\">\n                <p><strong>\u2139\ufe0f Note:<\/strong> The Rz \u2248 4\u00d7Ra approximation is a rough guide for typical machined surfaces. The actual ratio depends on the surface profile shape and machining process, and can range from 3 to 8.<\/p>\n            <\/div>\n\n            <h3>CLA \/ AA Conversion<\/h3>\n            <div class=\"vc-formula-box\" id=\"vc-katex-4\"><\/div>\n            <p>CLA (Centre Line Average) and AA (Arithmetic Average) are older terms for Ra, expressed in microinches. 1 \u03bcm = 39.37 \u03bcin.<\/p>\n\n            <div class=\"vc-warning-box\">\n                <p style=\"margin:0;font-size:14px;color:var(--vc-ink-secondary);\"><strong>\u26a0\ufe0f Important:<\/strong> Conversions between Ra and Rz are approximate. For critical applications, measure the specific parameter required by the specification directly.<\/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\/general-tolerances-iso2768-1\/\">General Tolerances (ISO 2768-1)<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/hardness-converter\/\">Hardness Converter<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/universal-unit-converter\/\">Unit Converter<\/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.\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\u20132025 <a href=\"https:\/\/vibromera.eu\/\">Vibromera<\/a> \u2014 Engineering Calculators<\/p>\n    <p style=\"font-size:12px;margin-top:4px;\">Based on ISO 1302, ISO 4287. Last updated: February 2025<\/p>\n    <div class=\"vc-footer-links\">\n        <a href=\"\/calculators\/engineering-calculators\/\">All Calculators<\/a>\n        <a href=\"https:\/\/vibromera.eu\/contacts\/\">Contact<\/a>\n    <\/div>\n<\/footer>\n\n<\/div>\n\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/katex@0.16.11\/dist\/katex.min.js\"><\/script>\n<script>\n(function() {\n    'use strict';\n\n    var SLUG = 'surface-roughness-converter';\n\n    function $(id) { return document.getElementById(id); }\n    function fmt(n, d) { if(isNaN(n)||n===null) return '\u2014'; var f=n.toFixed(d===undefined?3:d); return f.replace(\/(\\.\\d*?)0+$\/,'$1').replace(\/\\.$\/,''); }\n\n    \/* \u2500\u2500 ROUGHNESS DATA \u2500\u2500 *\/\n    var data = [\n        { n:1,  ra:0.025, rz:0.1,   cla:1,    desc:'Mirror finish',  process:'Superfinishing, lapping' },\n        { n:2,  ra:0.05,  rz:0.2,   cla:2,    desc:'Mirror finish',  process:'Superfinishing, lapping' },\n        { n:3,  ra:0.1,   rz:0.4,   cla:4,    desc:'Very smooth',    process:'Lapping, honing' },\n        { n:4,  ra:0.2,   rz:0.8,   cla:8,    desc:'Smooth',         process:'Fine grinding, honing' },\n        { n:5,  ra:0.4,   rz:1.6,   cla:16,   desc:'Smooth',         process:'Fine grinding' },\n        { n:6,  ra:0.8,   rz:3.2,   cla:32,   desc:'Fine',           process:'Grinding, fine turning' },\n        { n:7,  ra:1.6,   rz:6.3,   cla:63,   desc:'Fine',           process:'Turning, milling' },\n        { n:8,  ra:3.2,   rz:12.5,  cla:125,  desc:'Medium',         process:'Turning, milling' },\n        { n:9,  ra:6.3,   rz:25,    cla:250,  desc:'Medium rough',   process:'Rough machining' },\n        { n:10, ra:12.5,  rz:50,    cla:500,  desc:'Rough',          process:'Rough machining' },\n        { n:11, ra:25,    rz:100,   cla:1000, desc:'Very rough',     process:'Casting, forging' },\n        { n:12, ra:50,    rz:200,   cla:2000, desc:'Very rough',     process:'Casting, forging, flame cut' }\n    ];\n\n    var hints = { ra:'(\u03bcm)', rz:'(\u03bcm)', class:'(1\u201312)', cla:'(\u03bcin)' };\n\n    \/* \u2500\u2500 FIND NEAREST CLASS \u2500\u2500 *\/\n    function findNearest(key, val) {\n        var best = null, bestDist = Infinity;\n        for (var i = 0; i < data.length; i++) {\n            var d = Math.abs(Math.log(data[i][key]) - Math.log(val));\n            if (d < bestDist) { bestDist = d; best = data[i]; }\n        }\n        return best;\n    }\n\n    \/* \u2500\u2500 CALCULATION \u2500\u2500 *\/\n    function calculate() {\n        var type = $('vc-type').value;\n        var val = parseFloat($('vc-val').value);\n        $('vc-val-hint').textContent = hints[type] || '';\n\n        if (!val || val <= 0) {\n            $('vc-results').classList.remove('vc-visible');\n            clearHighlight();\n            return;\n        }\n\n        var raVal, rzVal, claVal, row;\n\n        if (type === 'ra') {\n            raVal = val;\n            rzVal = val * 4;\n            claVal = val * 39.37;\n            row = findNearest('ra', val);\n        } else if (type === 'rz') {\n            rzVal = val;\n            raVal = val \/ 4;\n            claVal = raVal * 39.37;\n            row = findNearest('rz', val);\n        } else if (type === 'class') {\n            var n = Math.round(val);\n            if (n < 1) n = 1; if (n > 12) n = 12;\n            row = data[n - 1];\n            raVal = row.ra;\n            rzVal = row.rz;\n            claVal = row.cla;\n        } else if (type === 'cla') {\n            claVal = val;\n            raVal = val \/ 39.37;\n            rzVal = raVal * 4;\n            row = findNearest('cla', val);\n        }\n\n        \/\/ Display\n        $('vc-r-ra').innerHTML = fmt(raVal, raVal < 0.1 ? 3 : (raVal < 1 ? 2 : 1)) + ' <span class=\"vc-rcard-unit\">\u03bcm<\/span>';\n        $('vc-r-rz').innerHTML = fmt(rzVal, rzVal < 1 ? 2 : 1) + ' <span class=\"vc-rcard-unit\">\u03bcm<\/span>';\n        $('vc-r-class').innerHTML = row ? ('N' + row.n) : '\u2014';\n        $('vc-r-cla').innerHTML = fmt(claVal, claVal < 10 ? 1 : 0) + ' <span class=\"vc-rcard-unit\">\u03bcin<\/span>';\n        $('vc-r-desc').innerHTML = '<span style=\"font-size:18px;\">' + (row ? row.desc : '\u2014') + '<\/span>';\n        $('vc-r-process').innerHTML = '<span style=\"font-size:16px;\">' + (row ? row.process : '\u2014') + '<\/span>';\n\n        $('vc-results').classList.add('vc-visible');\n\n        \/\/ Highlight table\n        highlightRow(row);\n\n        \/\/ URL params\n        var u = new URL(window.location);\n        u.searchParams.set('type', type);\n        u.searchParams.set('val', val);\n        history.replaceState(null, '', u.toString());\n\n        \/\/ History\n        saveHistory({\n            type: type,\n            val: val,\n            _summary: (type === 'class' ? 'N' + Math.round(val) : val + ' ' + (type === 'cla' ? '\u03bcin' : '\u03bcm')) + ' \u2192 Ra ' + fmt(raVal, 3) + ' \u03bcm'\n        });\n    }\n\n    \/* \u2500\u2500 HIGHLIGHT TABLE \u2500\u2500 *\/\n    function clearHighlight() {\n        document.querySelectorAll('#vc-ref-table tr.vc-row-highlight').forEach(function(r) { r.classList.remove('vc-row-highlight'); });\n    }\n    function highlightRow(row) {\n        clearHighlight();\n        if (!row) return;\n        var rows = document.querySelectorAll('#vc-ref-table tbody tr');\n        for (var i = 0; i < rows.length; i++) {\n            if (parseInt(rows[i].getAttribute('data-n')) === row.n) {\n                rows[i].classList.add('vc-row-highlight');\n                break;\n            }\n        }\n    }\n\n    \/* \u2500\u2500 TYPE CHANGE \u2014 update hint \u2500\u2500 *\/\n    $('vc-type').addEventListener('change', function() {\n        $('vc-val-hint').textContent = hints[this.value] || '';\n        \/\/ If class type, set step to 1\n        if (this.value === 'class') {\n            $('vc-val').step = '1';\n            $('vc-val').min = '1';\n            $('vc-val').max = '12';\n        } else {\n            $('vc-val').step = 'any';\n            $('vc-val').min = '0';\n            $('vc-val').removeAttribute('max');\n        }\n    });\n\n    \/* \u2500\u2500 PRESETS \u2500\u2500 *\/\n    document.querySelectorAll('.vc-preset-btn').forEach(function(btn) {\n        btn.addEventListener('click', function(e) {\n            e.preventDefault();\n            $('vc-type').value = this.getAttribute('data-t');\n            $('vc-val').value = this.getAttribute('data-v');\n            $('vc-val-hint').textContent = hints[this.getAttribute('data-t')] || '';\n            calculate();\n        });\n    });\n\n    \/* \u2500\u2500 AUTO-CALCULATE \u2500\u2500 *\/\n    $('vc-form').addEventListener('input', calculate);\n    $('vc-form').addEventListener('change', calculate);\n\n    \/* \u2500\u2500 COPY \u2500\u2500 *\/\n    $('vc-copy-btn').addEventListener('click', function() {\n        var text = 'Surface Roughness Conversion\\n' +\n            '\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\n' +\n            'Ra: ' + $('vc-r-ra').textContent + '\\n' +\n            'Rz: ' + $('vc-r-rz').textContent + '\\n' +\n            'Class: ' + $('vc-r-class').textContent + '\\n' +\n            'CLA: ' + $('vc-r-cla').textContent + '\\n' +\n            'Description: ' + $('vc-r-desc').textContent + '\\n' +\n            'Process: ' + $('vc-r-process').textContent + '\\n' +\n            '\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\n' +\n            'vibromera.eu\/calculators\/surface-roughness-converter\/';\n\n        if (navigator.clipboard) {\n            navigator.clipboard.writeText(text).then(function() {\n                var btn = $('vc-copy-btn');\n                btn.classList.add('vc-copied');\n                btn.innerHTML = '<svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><polyline points=\"20 6 9 17 4 12\"\/><\/svg> Copied!';\n                setTimeout(function() {\n                    btn.classList.remove('vc-copied');\n                    btn.innerHTML = '<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> Copy';\n                }, 2000);\n            });\n        }\n    });\n\n    \/* \u2500\u2500 COLLAPSIBLE SECTIONS \u2500\u2500 *\/\n    document.querySelectorAll('.vc-section-toggle').forEach(function(btn) {\n        btn.addEventListener('click', function() {\n            var section = this.closest('.vc-section');\n            var isOpen = section.classList.contains('vc-open');\n            section.classList.toggle('vc-open');\n            this.setAttribute('aria-expanded', !isOpen);\n        });\n    });\n\n    \/* \u2500\u2500 FAQ \u2500\u2500 *\/\n    var faqData = [\n        { q: 'What is the difference between Ra and Rz?', a: '<p><strong>Ra<\/strong> (arithmetical mean roughness) is the average of absolute profile deviations from the mean line. It gives a good general indication of surface texture.<\/p><p><strong>Rz<\/strong> (maximum height) is based on the five highest peaks and five deepest valleys. It is more sensitive to individual scratches or peaks.<\/p><p>Ra is more commonly used internationally, while Rz is popular in European standards, especially for critical sealing surfaces.<\/p>' },\n        { q: 'How do I convert between Ra and Rz?', a: '<p>A commonly used approximation is:<\/p><ul><li><strong>Rz \u2248 4 \u00d7 Ra<\/strong> for typical machined surfaces<\/li><\/ul><p>However, the actual ratio depends on the surface profile. For ground surfaces it can be closer to 5\u20136\u00d7, while for turned surfaces 3\u20134\u00d7 is typical. For critical applications, measure the parameter directly rather than converting.<\/p>' },\n        { q: 'What is N class (roughness grade number)?', a: '<p>N classes (N1 through N12) are roughness grade numbers per ISO 1302. Each grade doubles the Ra value from the previous grade:<\/p><ul><li>N1 = 0.025 \u03bcm, N2 = 0.05 \u03bcm, N3 = 0.1 \u03bcm, \u2026<\/li><li>Each step is 2\u00d7 the previous Ra value<\/li><\/ul><p>N classes simplify specification on drawings by using a single number instead of the actual Ra value.<\/p>' },\n        { q: 'What is typical Ra for common machining operations?', a: '<p>Typical achievable Ra values:<\/p><ul><li><strong>Lapping \/ superfinishing:<\/strong> 0.025\u20130.1 \u03bcm (N1\u2013N3)<\/li><li><strong>Fine grinding \/ honing:<\/strong> 0.2\u20130.4 \u03bcm (N4\u2013N5)<\/li><li><strong>Grinding \/ fine turning:<\/strong> 0.8\u20131.6 \u03bcm (N6\u2013N7)<\/li><li><strong>Turning \/ milling:<\/strong> 3.2\u20136.3 \u03bcm (N8\u2013N9)<\/li><li><strong>Rough machining:<\/strong> 6.3\u201312.5 \u03bcm (N9\u2013N10)<\/li><li><strong>Casting \/ forging:<\/strong> 25\u201350 \u03bcm (N11\u2013N12)<\/li><\/ul>' },\n        { q: 'What Ra is recommended for bearing seats?', a: '<p>Standard bearing manufacturer recommendations:<\/p><ul><li><strong>Shaft seat:<\/strong> Ra 0.8 \u03bcm (N6) for normal bearings, Ra 0.4 \u03bcm (N5) for precision bearings<\/li><li><strong>Housing bore:<\/strong> Ra 1.6 \u03bcm (N7) for normal, Ra 0.8 \u03bcm (N6) for precision<\/li><li><strong>Thrust faces:<\/strong> Ra 1.6 \u03bcm (N7)<\/li><\/ul><p>Always check the specific bearing manufacturer\\'s catalog for exact requirements.<\/p>' }\n    ];\n\n    var faqList = $('vc-faq-list');\n    faqData.forEach(function(faq) {\n        faqList.innerHTML += '<div class=\"vc-faq-item\"><button type=\"button\" class=\"vc-faq-q\"><span>' + faq.q + '<\/span><svg class=\"vc-faq-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg><\/button><div class=\"vc-faq-a\"><div class=\"vc-faq-a-inner\">' + faq.a + '<\/div><\/div><\/div>';\n    });\n    faqList.addEventListener('click', function(e) {\n        var btn = e.target.closest('.vc-faq-q');\n        if (!btn) return;\n        btn.closest('.vc-faq-item').classList.toggle('vc-open');\n    });\n\n    \/* \u2500\u2500 HISTORY \u2500\u2500 *\/\n    function saveHistory(entry) {\n        var key = 'vc_history_' + SLUG;\n        var arr = [];\n        try { arr = JSON.parse(localStorage.getItem(key)) || []; } catch(e) {}\n        entry._ts = new Date().toISOString();\n        arr.unshift(entry);\n        if (arr.length > 10) arr = arr.slice(0, 10);\n        try { localStorage.setItem(key, JSON.stringify(arr)); } catch(e) {}\n    }\n\n    \/* \u2500\u2500 URL PARAMS \u2500\u2500 *\/\n    function loadParams() {\n        var p = new URLSearchParams(window.location.search);\n        if (p.has('type')) $('vc-type').value = p.get('type');\n        if (p.has('val')) $('vc-val').value = p.get('val');\n    }\n\n    \/* \u2500\u2500 KATEX \u2500\u2500 *\/\n    function renderFormulas() {\n        try {\n            katex.render('Ra = \\\\frac{1}{L} \\\\int_0^L |Z(x)|\\\\, dx', $('vc-katex-1'), { displayMode: true, throwOnError: false });\n            katex.render('Rz = \\\\frac{1}{5} \\\\sum_{i=1}^{5} Rz_i', $('vc-katex-2'), { displayMode: true, throwOnError: false });\n            katex.render('Rz \\\\approx 4 \\\\times Ra \\\\qquad \\\\text{(rough guide for machined surfaces)}', $('vc-katex-3'), { displayMode: true, throwOnError: false });\n            katex.render('\\\\text{CLA (\u03bcin)} = Ra\\\\text{ (\u03bcm)} \\\\times 39.37', $('vc-katex-4'), { displayMode: true, throwOnError: false });\n        } catch(e) {}\n    }\n\n    \/* \u2500\u2500 INIT \u2500\u2500 *\/\n    function init() {\n        loadParams();\n        renderFormulas();\n        calculate();\n    }\n\n    if (document.readyState === 'loading') {\n        document.addEventListener('DOMContentLoaded', init);\n    } else {\n        init();\n    }\n})();\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>Gratis online overflateruhetskonverter. Konverter mellom Ra, Rz, ruhetsklasse (N1\u2013N12) og CLA\/AA mikrotommerverdier. Inkluderer typiske maskineringsprosesser og beskrivelser av overflatefinish.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-100252","calculator","type-calculator","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator\/100252","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator"}],"about":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/types\/calculator"}],"version-history":[{"count":1,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator\/100252\/revisions"}],"predecessor-version":[{"id":100564,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator\/100252\/revisions\/100564"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/media?parent=100252"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/categories?post=100252"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/tags?post=100252"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}