{"id":100192,"date":"2026-02-15T20:25:59","date_gmt":"2026-02-15T20:25:59","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100192"},"modified":"2026-07-13T03:43:37","modified_gmt":"2026-07-13T03:43:37","slug":"power-unit-converter","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/bg\/calculators\/power-unit-converter\/","title":{"rendered":"Defined Power-Unit Converter"},"content":{"rendered":"\n<script type=\"application\/ld+json\">{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"Defined Power-Unit Converter\",\"description\":\"Converts signed power using explicit BIPM\/NIST definitions for W, kW, MW, mechanical\/electric horsepower, metric horsepower, Btu IT per hour, foot-pound-force per second, kcal IT per hour and refrigeration ton.\",\"url\":\"https:\/\/vibromera.eu\/calculators\/power-unit-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\":[\"Signed power conversion\",\"Explicit IT heat-unit basis\",\"Mechanical versus electric horsepower\",\"Exact SI prefix scaling\",\"No torque-speed pseudo-unit\"],\"keywords\":\"power unit conversion,watt,mechanical horsepower,metric horsepower,Btu IT per hour,kcal IT per hour\"}<\/script>\n<script type=\"application\/ld+json\">{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"Which horsepower does hp mean here?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"hp(mech) is 550 international foot-pound-force per second, about 745.699871582 W. Electric horsepower is shown separately as exactly 746 W.\"}},{\"@type\":\"Question\",\"name\":\"Which Btu is used?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The converter uses the International Table Btu, exactly 1055.05585262 J, and labels it BtuIT.\"}},{\"@type\":\"Question\",\"name\":\"Which kilocalorie is used?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The converter uses the International Table kilocalorie, exactly 4186.8 J, and labels it kcalIT.\"}},{\"@type\":\"Question\",\"name\":\"Can power be negative?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Yes. A signed convention may represent opposite power-flow direction; conversion preserves the sign without assigning a physical interpretation.\"}}]}<\/script>\n<style>:root{--s:#fff;--sa:#f8f6f2;--i:#1a1a1a;--is:#5a5650;--im:#8a857e;--a:#8b572f;--al:#faf1e8;--b:#d9d4cc;--bl:#e8e4dd;--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-label{font-size:12px;font-weight:600;letter-spacing:.04em;text-transform:uppercase;color:var(--is);margin-bottom:6px}.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-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:1800px;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 18px var(--m);overflow-wrap:anywhere}.vc-primary .vc-rcard-value{font-size:24px;color:var(--a)}.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-table{width:100%;border-collapse:collapse;font-size:13px}.vc-table th,.vc-table td{padding:9px;border:1px solid var(--bl);text-align:left}.vc-table th{background:var(--sa)}.vc-warning{padding:14px;background:#fef9e8;border-left:3px solid #8a6500;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-primary{grid-column:1}}<\/style>\n<div class=\"vc-calculator\"><header class=\"vc-header\"><p class=\"vc-header-eyebrow\">Explicit unit definitions \u2014 sign preserved<\/p><h1 class=\"vc-header-title\">Defined Power-Unit Converter<\/h1><p class=\"vc-header-subtitle\">Convert a signed power value through watts using explicit SI, International Table heat-unit and horsepower definitions. Ambiguous \u201cBTU\u201d, \u201ckcal\u201d and \u201chp\u201d labels are qualified.<\/p><div class=\"vc-badges\"><span class=\"vc-badge\">W = J\/s<\/span><span class=\"vc-badge\">hp(mech) \u2260 hp(electric)<\/span><span class=\"vc-badge\">BtuIT\/h<\/span><span class=\"vc-badge\">kcalIT\/h<\/span><\/div><\/header>\n<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-value\">Signed power value<\/label><input class=\"vc-input\" id=\"vc-value\" inputmode=\"decimal\"><\/div><div class=\"vc-field\"><label class=\"vc-label\" for=\"vc-unit\">Defined input unit<\/label><select class=\"vc-select\" id=\"vc-unit\"><option value=\"W\">W<\/option><option value=\"kW\">kW<\/option><option value=\"MW\">MW<\/option><option value=\"hp_mech\">hp(mech)<\/option><option value=\"hp_electric\">hp(electric)<\/option><option value=\"PS\">PS \/ metric hp<\/option><option value=\"BtuIT_h\">BtuIT\/h<\/option><option value=\"ftlbf_s\">ft\u00b7lbf\/s<\/option><option value=\"kcalIT_h\">kcalIT\/h<\/option><option value=\"TR_IT\">ton of refrigeration (IT)<\/option><\/select><\/div><\/div><div class=\"vc-validation\" id=\"vc-validation\" role=\"status\" aria-live=\"polite\"><\/div><\/form>\n<div class=\"vc-results\" id=\"vc-results\"><div class=\"vc-result-grid\"><div class=\"vc-rcard vc-primary\"><div class=\"vc-rcard-label\">SI power<\/div><div class=\"vc-rcard-value\" id=\"vc-r-si\">\u2014<\/div><\/div><div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Mechanical \/ electric horsepower<\/div><div class=\"vc-rcard-value\" id=\"vc-r-hp\">\u2014<\/div><\/div><div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Metric horsepower<\/div><div class=\"vc-rcard-value\" id=\"vc-r-ps\">\u2014<\/div><\/div><div class=\"vc-rcard\"><div class=\"vc-rcard-label\">International Table heat-rate units<\/div><div class=\"vc-rcard-value\" id=\"vc-r-heat\">\u2014<\/div><\/div><div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Foot-pound-force rate<\/div><div class=\"vc-rcard-value\" id=\"vc-r-ft\">\u2014<\/div><\/div><div class=\"vc-rcard\"><div class=\"vc-rcard-label\">Refrigeration ton (IT)<\/div><div class=\"vc-rcard-value\" id=\"vc-r-tr\">\u2014<\/div><\/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\">Definitions and factors<\/span><span>\u2304<\/span><\/button><div class=\"vc-section-body\"><div class=\"vc-section-inner vc-theory\"><p>The BIPM SI Brochure defines watt as J\/s. Decimal SI prefixes are exact. NIST SP811 distinguishes International Table and thermochemical heat units;this converter uses only the explicitly labelled IT variants.<\/p><table class=\"vc-table\"><thead><tr><th>Unit<\/th><th>Watts per unit<\/th><th>Basis<\/th><\/tr><\/thead><tbody><tr><td>W<\/td><td>1<\/td><td>SI coherent derived unit<\/td><\/tr><tr><td>kW \/ MW<\/td><td>1000 \/ 1000000<\/td><td>Exact SI prefixes<\/td><\/tr><tr><td>hp(mech)<\/td><td>745.69987158227022<\/td><td>550 international ft\u00b7lbf\/s<\/td><\/tr><tr><td>hp(electric)<\/td><td>746<\/td><td>Exact defined unit<\/td><\/tr><tr><td>PS<\/td><td>735.49875<\/td><td>75 kgf\u00b7m\/s with gn=9.80665 m\/s\u00b2<\/td><\/tr><tr><td>BtuIT\/h<\/td><td>0.293071070172222&#8230;<\/td><td>1055.05585262 J \/ 3600 s<\/td><\/tr><tr><td>ft\u00b7lbf\/s<\/td><td>1.3558179483314004<\/td><td>0.3048 m \u00d7 4.4482216152605 N \/ s<\/td><\/tr><tr><td>kcalIT\/h<\/td><td>1.163<\/td><td>4186.8 J \/ 3600 s<\/td><\/tr><tr><td>TR(IT)<\/td><td>3516.852842066666&#8230;<\/td><td>12000 BtuIT\/h<\/td><\/tr><\/tbody><\/table><div class=\"vc-warning\"><strong>Conversion only.<\/strong> Sign meaning, input measurement uncertainty, shaft\/electrical\/thermal boundaries, efficiency and time averaging are not inferred. Torque\u00d7rpm is a separate physical calculation `P=T\u00b72\u03c0n\/60`, not a power unit;the old rounded `\/9549` pseudo-unit route was removed.<\/div><h3>Sources<\/h3><p><a href=\"https:\/\/www.bipm.org\/en\/publications\/si-brochure\/\" target=\"_blank\" rel=\"noopener\">BIPM SI Brochure 9th edition,updated2026<\/a>; <a href=\"https:\/\/www.nist.gov\/pml\/special-publication-811\/nist-guide-si-appendix-b-conversion-factors\/nist-guide-si-appendix-b9\" target=\"_blank\" rel=\"noopener\">NIST SP811 Appendix B.9<\/a>; <a href=\"https:\/\/www.nist.gov\/pml\/special-publication-811\/nist-guide-si-footnotes\" target=\"_blank\" rel=\"noopener\">NIST conversion footnotes<\/a>.<\/p><\/div><\/div><\/div>\n<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 factors reviewed 13 July 2026<\/footer><\/div>\n<script>(function(){'use strict';function $(id){return document.getElementById(id)}function readSigned(raw){var t=String(raw??'').trim();if(!t||(t.includes(',')&&t.includes('.')))return null;t=t.replace(',','.');if(!\/^[+-]?(?:\\d+(?:\\.\\d*)?|\\.\\d+)$\/.test(t))return null;var v=Number(t);return Number.isFinite(v)?v:null}function fmt(v){if(v===0)return'0';if(Math.abs(v)>=1e12||Math.abs(v)<1e-9)return v.toExponential(12);return Number(v.toPrecision(14)).toString()}var F={W:1,kW:1000,MW:1e6,hp_mech:550*.3048*4.4482216152605,hp_electric:746,PS:75*9.80665,BtuIT_h:1055.05585262\/3600,ftlbf_s:.3048*4.4482216152605,kcalIT_h:4186.8\/3600,TR_IT:12000*1055.05585262\/3600};function hide(m){$('vc-results').classList.remove('vc-visible');$('vc-validation').textContent=m||''}function calc(){var v=readSigned($('vc-value').value),u=$('vc-unit').value;if(v===null||!Object.hasOwn(F,u))return hide('Enter one complete signed finite value and select a defined unit.');var W=v*F[u];if(!Number.isFinite(W))return hide('Converted power is not finite.');$('vc-r-si').textContent=fmt(W)+' W | '+fmt(W\/1000)+' kW | '+fmt(W\/1e6)+' MW';$('vc-r-hp').textContent=fmt(W\/F.hp_mech)+' hp(mech) | '+fmt(W\/F.hp_electric)+' hp(electric)';$('vc-r-ps').textContent=fmt(W\/F.PS)+' PS';$('vc-r-heat').textContent=fmt(W\/F.BtuIT_h)+' BtuIT\/h | '+fmt(W\/F.kcalIT_h)+' kcalIT\/h';$('vc-r-ft').textContent=fmt(W\/F.ftlbf_s)+' ft\u00b7lbf\/s';$('vc-r-tr').textContent=fmt(W\/F.TR_IT)+' TR(IT)';$('vc-validation').textContent='';$('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=[['Why are there two horsepower outputs?','Mechanical horsepower and electric horsepower have different defined watt values.They are not silently treated as interchangeable.'],['Why does the converter say BtuIT?','Several historical Btu definitions exist.The explicit International Table definition prevents an otherwise hidden conversion ambiguity.'],['Is negative power an error?','No.The converter preserves a signed value;the user must define whether the sign represents import\/export,driving\/braking or another convention.'],['Where is torque times RPM?','It is a power calculation requiring torque and angular-speed definitions,not a unit conversion.Use P=T\u00b72\u03c0n\/60 with controlled shaft quantities.']];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 signed power using explicit BIPM\/NIST definitions for SI,mechanical\/electric horsepower,metric horsepower and International Table heat-rate units.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-100192","calculator","type-calculator","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/bg\/wp-json\/wp\/v2\/calculator\/100192","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/bg\/wp-json\/wp\/v2\/calculator"}],"about":[{"href":"https:\/\/vibromera.eu\/bg\/wp-json\/wp\/v2\/types\/calculator"}],"version-history":[{"count":2,"href":"https:\/\/vibromera.eu\/bg\/wp-json\/wp\/v2\/calculator\/100192\/revisions"}],"predecessor-version":[{"id":102530,"href":"https:\/\/vibromera.eu\/bg\/wp-json\/wp\/v2\/calculator\/100192\/revisions\/102530"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/bg\/wp-json\/wp\/v2\/media?parent=100192"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/bg\/wp-json\/wp\/v2\/categories?post=100192"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/bg\/wp-json\/wp\/v2\/tags?post=100192"}],"curies":[{"name":"\u0440\u0430\u0431\u043e\u0442\u043d\u0430 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