{"id":100187,"date":"2026-02-15T20:25:44","date_gmt":"2026-02-15T20:25:44","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100187"},"modified":"2026-07-13T02:59:33","modified_gmt":"2026-07-13T02:59:33","slug":"pipe-thread-converter","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/fr\/calculators\/pipe-thread-converter\/","title":{"rendered":"Documented ISO Pipe-Thread Pitch Arithmetic"},"content":{"rendered":"\n<script type=\"application\/ld+json\">{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"Documented ISO Pipe-Thread Pitch Arithmetic\",\"description\":\"Converts a documented threads-per-inch value into pitch while recording the controlled ISO 228-1 or ISO 7-1 designation basis. It does not invent standard diameters, tapping drills, interchangeability or sealant instructions.\",\"url\":\"https:\/\/vibromera.eu\/calculators\/pipe-thread-converter\/\",\"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\":[\"Documented TPI to pitch arithmetic\",\"ISO 228-1 versus ISO 7-1 scope boundary\",\"Optional sourced reference diameter\",\"No tapping-drill table\",\"No sealing recommendation\"],\"keywords\":\"ISO 228-1,ISO 7-1,pipe thread pitch,TPI conversion,controlled thread designation\"}<\/script>\n<script type=\"application\/ld+json\">{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"Does this identify a pipe thread from measured OD?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No. Identification and conformity require controlled designation data and the applicable gauging procedure; no nearest-size inference is made.\"}},{\"@type\":\"Question\",\"name\":\"Does it provide tapping-drill sizes?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No. Drill\/tap preparation depends on the exact thread, tool, material, engagement and controlled manufacturing process.\"}},{\"@type\":\"Question\",\"name\":\"Does ISO 228-1 make a pressure-tight joint on the thread?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No. ISO 228-1 covers parallel fastening pipe threads not suitable for pressure-tight joints made on the thread; sealing must be provided outside the threads when required.\"}},{\"@type\":\"Question\",\"name\":\"Does the worksheet recommend PTFE tape or thread sealant?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"No. Seal selection and application require the exact connection, fluid, pressure, temperature, materials, regulations and manufacturer procedure.\"}}]}<\/script>\n<style>:root{--s:#fff;--sa:#f8f6f2;--i:#1a1a1a;--is:#5a5650;--im:#8a857e;--a:#4e5f87;--al:#eef1f8;--b:#d9d4cc;--bl:#e8e4dd;--y:#8a6500;--yl:#fef9e8;--r:#a12b2b;--f:'DM Sans',sans-serif;--m:'JetBrains Mono',monospace;--d:'Fraunces',serif}.vc-calculator{font-family:var(--f);font-size:15px;line-height:1.65;color:var(--i);max-width:960px;margin:auto;padding:20px 16px 40px}.vc-calculator *{box-sizing:border-box}.vc-header{text-align:center;padding:48px 20px 40px;border-bottom:3px solid var(--a)}.vc-header-eyebrow{font:500 11px var(--m);letter-spacing:.15em;text-transform:uppercase;color:var(--a)}.vc-header-title{font:800 clamp(24px,4vw,36px)\/1.15 var(--d);margin:10px 0 14px}.vc-header-subtitle{max-width:760px;margin:auto;color:var(--is)}.vc-badges{display:flex;gap:8px;justify-content:center;flex-wrap:wrap;margin-top:18px}.vc-badge{font:500 11px var(--m);padding:4px 10px;border:1px solid var(--b);border-radius:4px}.vc-card,.vc-section{background:var(--s);border:1px solid var(--b);border-radius:12px;overflow:hidden;margin-top:28px}.vc-form{padding:24px}.vc-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.vc-field{display:flex;flex-direction:column}.vc-full{grid-column:1\/-1}.vc-label{font-size:12px;font-weight:600;letter-spacing:.04em;text-transform:uppercase;color:var(--is);margin-bottom:6px}.vc-hint{font-weight:400;text-transform:none;letter-spacing:0;color:var(--im)}.vc-input,.vc-select{width:100%;padding:10px 12px;border:1.5px solid var(--b);border-radius:6px;font:14px var(--f);background:var(--s)}.vc-check{display:flex;gap:10px;padding:12px;border:1px solid var(--bl);border-radius:6px;background:var(--sa);font-size:13px;color:var(--is)}.vc-check input{margin-top:4px}.vc-validation{min-height:22px;color:var(--r);font-size:13px;margin-top:10px}.vc-results{border-top:1px solid var(--bl);background:var(--sa);padding:0;max-height:0;overflow:hidden}.vc-results.vc-visible{max-height:1200px;padding:24px}.vc-result-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}.vc-rcard{background:var(--s);border:1px solid var(--bl);border-radius:8px;padding:16px}.vc-primary{grid-column:1\/-1;border:2px solid var(--a);background:var(--al)}.vc-rcard-label{font:500 10px var(--m);letter-spacing:.1em;text-transform:uppercase;color:var(--im)}.vc-rcard-value{font:600 19px var(--m);overflow-wrap:anywhere}.vc-primary .vc-rcard-value{font-size:24px;color:var(--a)}.vc-status{grid-column:1\/-1;padding:12px;background:var(--yl);border-left:3px solid var(--y);font-size:13px;color:var(--is)}.vc-section-toggle{width:100%;display:flex;justify-content:space-between;padding:18px 24px;border:0;background:transparent;cursor:pointer;text-align:left}.vc-section-title{font:700 18px var(--d)}.vc-section-body{max-height:0;overflow:hidden}.vc-section.vc-open .vc-section-body{max-height:15000px}.vc-section-inner{padding:0 24px 24px;border-top:1px solid var(--bl)}.vc-theory h3{font:700 17px var(--d);margin:24px 0 8px}.vc-theory p,.vc-theory li{font-size:14px;color:var(--is)}.vc-formula{padding:14px;border:2px solid var(--b);border-radius:6px;background:var(--sa);text-align:center;font:500 14px var(--m);margin:12px 0}.vc-warning{padding:14px;background:var(--yl);border-left:3px solid var(--y);color:var(--is)}.vc-faq-item{border:1px solid var(--bl);margin-top:8px}.vc-faq-q{width:100%;padding:14px;border:0;background:var(--sa);text-align:left;font-weight:600}.vc-faq-a{display:none;padding:14px;color:var(--is)}.vc-faq-item.vc-open .vc-faq-a{display:block}.vc-footer{text-align:center;padding:30px;color:var(--im);font-size:13px}@media(max-width:600px){.vc-grid,.vc-result-grid{grid-template-columns:1fr}.vc-full,.vc-primary,.vc-status{grid-column:1}}<\/style>\n<div class=\"vc-calculator\"><header class=\"vc-header\"><p class=\"vc-header-eyebrow\">Source-gated thread record \u2014 not automatic identification<\/p><h1 class=\"vc-header-title\">Documented ISO Pipe-Thread Pitch Arithmetic<\/h1><p class=\"vc-header-subtitle\">Convert a documented TPI value to pitch and preserve the exact controlled designation\/source. No ISO diameter, tolerance, tapping-drill, gauge or sealing row is guessed.<\/p><div class=\"vc-badges\"><span class=\"vc-badge\">No nearest-size match<\/span><span class=\"vc-badge\">No drill table<\/span><span class=\"vc-badge\">No sealant advice<\/span><\/div><\/header><div class=\"vc-card\"><form class=\"vc-form\" id=\"vc-form\" autocomplete=\"off\" novalidate><div class=\"vc-grid\"><div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-family\">Controlled standard family<\/label><select class=\"vc-select\" id=\"vc-family\"><option value=\"228\">ISO 228-1 fastening thread \u2014 pressure-tight joint not made on thread<\/option><option value=\"7\">ISO 7-1 pressure-tight joint thread family<\/option><\/select><\/div><div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-designation\">Exact controlled thread designation<\/label><input class=\"vc-input\" id=\"vc-designation\" type=\"text\" placeholder=\"as stated by drawing\/specification; do not infer\"><\/div><div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-tpi\">Documented threads per inch TPI<\/label><input class=\"vc-input\" id=\"vc-tpi\" inputmode=\"decimal\"><\/div><div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-diameter\">Documented reference diameter <span class=\"vc-hint\">(optional; not identified)<\/span><\/label><input class=\"vc-input\" id=\"vc-diameter\" inputmode=\"decimal\"><\/div><div class=\"vc-field vc-full\"><label class=\"vc-label\" for=\"vc-diameter-unit\">Optional diameter unit<\/label><select class=\"vc-select\" id=\"vc-diameter-unit\"><option value=\"mm\">mm<\/option><option value=\"in\">in<\/option><\/select><\/div><div class=\"vc-field vc-full\"><label class=\"vc-label\" for=\"vc-source\">Standard\/drawing\/gauge record source<\/label><input class=\"vc-input\" id=\"vc-source\" type=\"text\" placeholder=\"standard edition\/corrigendum; drawing\/component ID; sex\/form\/class; dimension\/gauge record; revision\/date\"><\/div><div class=\"vc-field vc-full\"><label class=\"vc-check\" for=\"vc-gate\"><input id=\"vc-gate\" type=\"checkbox\"><span>The designation, TPI and optional diameter were taken from one controlled record; they are not inferred from a casual measurement. The responsible process separately verifies external\/internal form, parallel\/taper status, class\/tolerance, handedness, engagement, gauging, material, port\/stud compatibility, sealing method, pressure\/temperature rating and conformity under the complete applicable current documents.<\/span><\/label><\/div><\/div><div class=\"vc-validation\" id=\"vc-validation\" role=\"status\" aria-live=\"polite\"><\/div><\/form><div class=\"vc-results\" id=\"vc-results\"><div class=\"vc-result-grid\"><div class=\"vc-rcard vc-primary\"><div class=\"vc-rcard-label\">Pitch from documented TPI<\/div><div class=\"vc-rcard-value\" id=\"vc-r-pitch\">\u2014<\/div><\/div><div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Controlled family \/ designation<\/div><div class=\"vc-rcard-value\" id=\"vc-r-id\">\u2014<\/div><\/div><div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Documented TPI<\/div><div class=\"vc-rcard-value\" id=\"vc-r-tpi\">\u2014<\/div><\/div><div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Optional sourced diameter<\/div><div class=\"vc-rcard-value\" id=\"vc-r-diameter\">\u2014<\/div><\/div><div class=\"vc-status\" id=\"vc-r-note\">Pitch unit arithmetic only.<\/div><\/div><\/div><\/div>\n<div class=\"vc-section vc-open\"><button class=\"vc-section-toggle\" type=\"button\" aria-expanded=\"true\"><span class=\"vc-section-title\">Equation and ISO boundary<\/span><span>\u2304<\/span><\/button><div class=\"vc-section-body\"><div class=\"vc-section-inner vc-theory\"><div class=\"vc-formula\">pitch [in\/thread]=1\/TPI;&nbsp; pitch [mm\/thread]=25.4\/TPI<\/div><p>The 25.4 mm\/in conversion is exact. This is unit arithmetic applied to a documented TPI; it is not an ISO dimensional lookup or conformity calculation.<\/p><h3>ISO 228-1:2000<\/h3><p>Current edition 4, confirmed 2022. It covers parallel external and internal fastening pipe threads from 1\/16 through 6. These threads are not suitable for pressure-tight joints made on the thread; when sealing is required, it is provided by tightening surfaces outside the threads with an appropriate seal. ISO 228-2:1987 covers verification by gauges.<\/p><h3>ISO 7-1:1994 with Cor 1:2007<\/h3><p>Current edition 3, confirmed 2026. It specifies designation, dimensions and tolerances for pipe threads where pressure-tight joints are made on the threads, from 1\/16 through 6. ISO 7-2:2000 covers limit-gauge verification and notes that gauges alone do not completely control all thread quality\/dimensions.<\/p><div class=\"vc-warning\"><strong>NEEDS_LICENSED_SOURCE:<\/strong> exact designation-specific diameters, tolerances, TPI rows, tapping-drill values, gauge limits and connection\/seal rules. No such row is copied or reconstructed here.<\/div><h3>Not determined<\/h3><ul><li>Thread identity from OD\/TPI or interchangeability with NPT\/other families.<\/li><li>External\/internal, parallel\/taper, class\/tolerance or conformity.<\/li><li>Tapping drill, tap engagement, tool allowance or manufacturing process.<\/li><li>Seal type, tape dimensions\/wrap count, torque, pressure rating or service compatibility.<\/li><\/ul><h3>Sources<\/h3><p><a href=\"https:\/\/www.iso.org\/standard\/33777.html\" target=\"_blank\" rel=\"noopener\">ISO 228-1:2000<\/a>; <a href=\"https:\/\/www.iso.org\/standard\/4104.html\" target=\"_blank\" rel=\"noopener\">ISO 228-2:1987<\/a>; <a href=\"https:\/\/www.iso.org\/standard\/20819.html\" target=\"_blank\" rel=\"noopener\">ISO 7-1:1994<\/a>; <a href=\"https:\/\/www.iso.org\/standard\/46479.html\" target=\"_blank\" rel=\"noopener\">ISO 7-1:1994\/Cor 1:2007<\/a>; <a href=\"https:\/\/www.iso.org\/standard\/20820.html\" target=\"_blank\" rel=\"noopener\">ISO 7-2:2000<\/a>; <a href=\"https:\/\/www.nist.gov\/pml\/owm\/si-units-length\" target=\"_blank\" rel=\"noopener\">NIST exact international inch<\/a>.<\/p><\/div><\/div><\/div><div class=\"vc-section\"><button class=\"vc-section-toggle\" type=\"button\" aria-expanded=\"false\"><span class=\"vc-section-title\">Frequently asked questions<\/span><span>\u2304<\/span><\/button><div class=\"vc-section-body\"><div class=\"vc-section-inner\"><div id=\"vc-faq-list\"><\/div><\/div><\/div><\/div><footer class=\"vc-footer\">\u00a9 2024\u20132026 Vibromera \u2014 reviewed 13 July 2026<\/footer><\/div>\n<script>(function(){'use strict';function $(id){return document.getElementById(id)}function read(raw){var t=String(raw||'').trim();if(!t||(t.includes(',')&&t.includes('.')))return null;t=t.replace(',','.');if(!\/^(?:\\d+(?:\\.\\d*)?|\\.\\d+)$\/.test(t))return null;var v=Number(t);return Number.isFinite(v)&&v>0?v:null}function fmt(v){if(Math.abs(v)>=1e9||Math.abs(v)<1e-7)return v.toExponential(8);return Number(v.toPrecision(12)).toString()}function hide(m){$('vc-results').classList.remove('vc-visible');$('vc-validation').textContent=m||''}function calc(){var designation=$('vc-designation').value.trim(),source=$('vc-source').value.trim();if(!designation)return hide('Enter the exact controlled thread designation.');if(!source)return hide('Enter the controlled standard\/drawing\/gauge record source.');if(!$('vc-gate').checked)return hide('Confirm the controlled record and separate conformity\/sealing decisions.');var tpi=read($('vc-tpi').value);if(tpi===null)return hide('Enter a positive complete documented TPI value.');var rawD=String($('vc-diameter').value||'').trim(),d=null;if(rawD){d=read(rawD);if(d===null)return hide('Optional documented diameter must be a positive complete number.')}var pitchIn=1\/tpi,pitchMm=25.4\/tpi,family=$('vc-family').value==='228'?'ISO 228-1:2000':'ISO 7-1:1994 + Cor 1:2007';if(![pitchIn,pitchMm].every(function(x){return Number.isFinite(x)&&x>0}))return hide('Pitch arithmetic did not produce finite positive results.');$('vc-r-pitch').textContent=fmt(pitchMm)+' mm\/thread | '+fmt(pitchIn)+' in\/thread';$('vc-r-id').textContent=family+' | '+designation;$('vc-r-tpi').textContent=fmt(tpi)+' threads\/in';$('vc-r-diameter').textContent=d===null?'Not entered':($('vc-diameter-unit').value==='in'?fmt(d*25.4)+' mm | '+fmt(d)+' in':fmt(d)+' mm | '+fmt(d\/25.4)+' in');$('vc-r-note').textContent='Unit arithmetic from documented TPI only. No thread identification, diameter\/tolerance\/drill lookup, gauging, interchangeability, sealing or conformity decision is generated.';$('vc-validation').textContent='';$('vc-results').classList.add('vc-visible')}$('vc-form').addEventListener('input',calc);$('vc-form').addEventListener('change',calc);document.querySelectorAll('.vc-section-toggle').forEach(function(b){b.addEventListener('click',function(){var s=this.closest('.vc-section');s.classList.toggle('vc-open');this.setAttribute('aria-expanded',String(s.classList.contains('vc-open')))})});var faq=[['Can I identify G1\/2 from 20.9 mm and 14 TPI?','Not with this worksheet. Use the controlled dimensions, tolerances and gauges from the complete applicable standard and component record.'],['Why are tapping drills removed?','They were unsourced and identical for parallel\/taper rows. Tooling depends on the exact controlled manufacturing process.'],['Does ISO 228-1 mean BSPP seals with any O-ring?','No. ISO 228-1 says the thread itself is not the pressure-tight joint. The complete port\/stud\/seal standard and application govern the sealing design.'],['Can I connect BSP to NPT?','No compatibility decision is made here. Use a specified rated adapter\/connection and the applicable controlled standards.']];var l=$('vc-faq-list');faq.forEach(function(x){var w=document.createElement('div');w.className='vc-faq-item';var b=document.createElement('button');b.type='button';b.className='vc-faq-q';b.textContent=x[0];var a=document.createElement('div');a.className='vc-faq-a';a.textContent=x[1];w.appendChild(b);w.appendChild(a);l.appendChild(w)});l.addEventListener('click',function(e){var b=e.target.closest('.vc-faq-q');if(b)b.closest('.vc-faq-item').classList.toggle('vc-open')});hide('')})();<\/script>\n","protected":false},"excerpt":{"rendered":"<p>Convert a documented threads-per-inch value to pitch without inventing ISO dimensions,tapping drills,thread identity,interchangeability or sealing instructions.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-100187","calculator","type-calculator","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/calculator\/100187","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/calculator"}],"about":[{"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/types\/calculator"}],"version-history":[{"count":3,"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/calculator\/100187\/revisions"}],"predecessor-version":[{"id":102525,"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/calculator\/100187\/revisions\/102525"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/media?parent=100187"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/categories?post=100187"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/fr\/wp-json\/wp\/v2\/tags?post=100187"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}