{"id":55826,"date":"2015-10-24T15:57:57","date_gmt":"2015-10-24T13:57:57","guid":{"rendered":"http:\/\/wpcalc.com\/?p=55826"},"modified":"2026-09-28T09:22:11","modified_gmt":"2026-09-28T06:22:11","slug":"heat-transfer","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/converters\/heat-transfer\/","title":{"rendered":"Heat Transfer Converter"},"content":{"rendered":"<section class=\"not-prose calculator-box\" aria-labelledby=\"calculator-title\"><div class=\"flex items-baseline sm:items-center justify-between gap-2 sm:gap-3\"><div class=\"flex flex-col sm:flex-row sm:items-center gap-2\"><span class=\"icon icon-calculator text-primary-700! text-base! dark:text-primary-300!\" aria-hidden=\"true\"><\/span><h2 id=\"calculator-title\" class=\"text-lg font-display font-bold\">Convert Heat Transfer Between Units<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"55826\" data-favorite-title=\"Heat Transfer\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/converters\/heat-transfer\/\" data-favorite-excerpt=\"Convert a heat transfer rate between watts, kilowatts, megawatts, calories per second, and BTU-based units. Enter a rate, then select the From unit and To unit.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-physic\">\n    <span class=\"icon icon-shape-star-empty\" aria-hidden=\"true\"><\/span>\n  <\/button>\n  <div class=\"calcdash-favorite__tip\" aria-hidden=\"true\">\n   <span class=\"favorite-tooltip\" id=\"favorite-tooltip\"><\/span>\n  <\/div>\n  <span class=\"sr-only\" role=\"status\" id=\"favorite-status\"><\/span>\n<\/div><\/div><form action=\"https:\/\/wpcalc.com\/en\/converters\/heat-transfer\/\" method=\"POST\" class=\"calculator\" id=\"calculator-55826\" data-post=\"55826\"><fieldset class=\"fieldset-input\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field is-single\" id=\"input-1\"><label for=\"field-1\">Heat transfer rate<\/label><input type=\"text\" name=\"heat_transfer_rate\" id=\"field-1\" aria-describedby=\"calc-unit-1 calc-info-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"500\"\/><div class=\"unit\" id=\"calc-unit-1\"><\/div><small id=\"calc-info-1\">Enter the heat transfer value to convert<\/small><\/div><div class=\"field\" id=\"input-2\"><label for=\"field-2\">From unit<\/label><div class=\"grid grid-cols-1\"><select id=\"field-2\" name=\"from_unit\"><option value=\"W\">Watt (W)<\/option><option value=\"kW\">Kilowatt (kW)<\/option><option value=\"MW\">Megawatt (MW)<\/option><option value=\"cal\/s\">Calorie per second (cal\/s)<\/option><option value=\"kcal\/s\">Kilocalorie per second (kcal\/s)<\/option><option value=\"BTU\/s\">BTU per second (BTU\/s)<\/option><option value=\"BTU\/min\">BTU per minute (BTU\/min)<\/option><option value=\"BTU\/h\">BTU per hour (BTU\/h)<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><div class=\"field\" id=\"input-3\"><label for=\"field-3\">To unit<\/label><div class=\"grid grid-cols-1\"><select id=\"field-3\" name=\"to_unit\"><option value=\"W\">Watt (W)<\/option><option value=\"kW\">Kilowatt (kW)<\/option><option value=\"MW\">Megawatt (MW)<\/option><option value=\"cal\/s\">Calorie per second (cal\/s)<\/option><option value=\"kcal\/s\">Kilocalorie per second (kcal\/s)<\/option><option value=\"BTU\/s\">BTU per second (BTU\/s)<\/option><option value=\"BTU\/min\">BTU per minute (BTU\/min)<\/option><option value=\"BTU\/h\">BTU per hour (BTU\/h)<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"55826\">Calculate<\/button><button type=\"reset\">Reset<\/button><\/div><div class=\"field is-checkbox hidden!\" id=\"field-auto-calc\"><input type=\"checkbox\" id=\"auto-calc\"><label for=\"auto-calc\">Calculate automatically<\/label><small>If enabled, the result will update automatically when you change any value.<\/small><\/div><div class=\"fieldset-result is-hidden\" aria-labelledby=\"result-title\" aria-live=\"polite\" role=\"region\"> <h3 class=\"result-title bg-gradient-to-r from-primary-50 to-gray-50 dark:from-primary-900 dark:to-gray-800\" id=\"result-title\"><span class=\"icon icon-s-pulse\" aria-hidden=\"true\"><\/span> Your Results<\/h3><div class=\"result-box\"><div class=\"field-result\" id=\"output-1\"><span class=\"field-title\"><span>Converted Heat Transfer<\/span><\/span><span class=\"field-value\" id=\"result-1\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copy Result\" aria-label=\"Copy Result\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><\/div><div class=\"result-actions\"><button type=\"button\" class=\"copy-link\"><svg viewBox=\"0 0 20 20\" fill=\"currentColor\" aria-hidden=\"true\"><path d=\"M12.232 4.232a2.5 2.5 0 0 1 3.536 3.536l-1.225 1.224a.75.75 0 0 0 1.061 1.06l1.224-1.224a4 4 0 0 0-5.656-5.656l-3 3a4 4 0 0 0 .225 5.865.75.75 0 0 0 .977-1.138 2.5 2.5 0 0 1-.142-3.667l3-3Z\"\/><path d=\"M11.603 7.963a.75.75 0 0 0-.977 1.138 2.5 2.5 0 0 1 .142 3.667l-3 3a2.5 2.5 0 0 1-3.536-3.536l1.225-1.224a.75.75 0 0 0-1.061-1.06l-1.224 1.224a4 4 0 1 0 5.656 5.656l3-3a4 4 0 0 0-.225-5.865Z\"\/><\/svg><span class=\"copy-link__text\">Copy link to this calculation<\/span><\/button><span class=\"sr-only\" role=\"status\" id=\"copy-link-status\"><\/span><\/div><\/div><a href=\"#respond\" class=\"hidden transition-opacity duration-300 opacity-0 w-50 text-sm justify-center items-center gap-2 px-4 py-2 rounded bg-gray-200 text-gray-700 hover:bg-gray-300\" id=\"leave-comment\"><span class=\"icon icon-comments\" aria-hidden=\"true\"><\/span>Leave a Comment<\/a><\/form><\/section><section id=\"calc-reactions\" class=\"not-prose hidden my-12 bg-gradient-to-r from-primary-50 to-gray-50 border border-indigo-100 rounded-xl px-6 py-4 shadow-sm\" data-post=\"55826\" aria-live=\"polite\" aria-labelledby=\"calc-reactions-title\"><p id=\"calc-reactions-title\" class=\"text-sm text-gray-500 text-center mb-2\">How did this result make you feel?<\/p><div role=\"group\" aria-labelledby=\"calc-reactions-title\" class=\"grid grid-cols-3 sm:flex sm:flex-row sm:justify-around gap-4 sm:items-center sm:flex-wrap\"><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"like\"><span class=\"reaction-count\" data-reaction-count=\"like\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude00 <\/span><span class=\"reaction-description font-medium\">Like <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"helpful\"><span class=\"reaction-count\" data-reaction-count=\"helpful\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\udca1 <\/span><span class=\"reaction-description font-medium\">Helpful <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"confused\"><span class=\"reaction-count\" data-reaction-count=\"confused\">1<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude15 <\/span><span class=\"reaction-description font-medium\">Confused <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"disappointed\"><span class=\"reaction-count\" data-reaction-count=\"disappointed\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude1e <\/span><span class=\"reaction-description font-medium\">Disappointed <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"inaccurate\"><span class=\"reaction-count\" data-reaction-count=\"inaccurate\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\u274c <\/span><span class=\"reaction-description font-medium\">Inaccurate <\/span><\/button><\/div><div id=\"reaction-message\" class=\"hidden mt-8 rounded-md border border-primary-100 bg-white\/50 backdrop-blur-sm px-4 py-2 text-sm text-center shadow-sm\"><\/div><\/section><div class=\"calcdash-ad not-prose calcdash-ad--calc_result calcdash-ad--in-article\"><ins class=\"adsbygoogle\" style=\"display:block\" data-ad-client=\"ca-pub-1721569815777345\" data-ad-slot=\"6317458308\" data-ad-layout=\"in-article\" data-ad-format=\"fluid\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/div>\n<style id=\"wpcoderpro-inline-1\">.formula-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section class=\"formula-box\" aria-labelledby=\"formula-title\">\r\n\t<div id=\"formula-title\" class=\"not-prose font-display mb-4\"><span class=\"icon icon-formula\" aria-hidden=\"true\"><\/span><h2>Heat Transfer Formula<\/h2><\/div>\r\n\t<figure class=\"not-prose formula\">\r\n\t\t<figcaption class=\"formula-title\">Formula<\/figcaption>\r\n\t\t<div class=\"text-base text-gray-800\" id=\"formula\">\n\\[\\dot Q_{\\mathrm{to}}=\\dot Q_{\\mathrm{from}}\\frac{f_{\\mathrm{from}}}{f_{\\mathrm{to}}}\\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(\\dot Q_{\\mathrm{from}}\\) \u2014 the entered heat transfer rate in the selected From unit<\/li>\n<li>\\(\\dot Q_{\\mathrm{to}}\\) \u2014 the converted heat transfer rate in the selected To unit<\/li>\n<li>\\(f_{\\mathrm{from}}\\) and \\(f_{\\mathrm{to}}\\) \u2014 the number of watts per unit for the selected units<\/li>\n<\/ul>\n<p>The converter first expresses the entered rate in watts, then divides by the watts-per-unit factor for the destination unit. Because these are rates of energy transfer, their conversion factors are the same as those used for power.<\/p>\n<p>\r\n<\/section>\n<style id=\"wpcoderpro-inline-459\">.calculation-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section id=\"calculation\" class=\"calculation-box\" aria-labelledby=\"calculation-title\">\r\n\t<div id=\"calculation-title\" class=\"not-prose font-display\"><span class=\"icon icon-unordered-list\" aria-hidden=\"true\"><\/span><h2>Heat Transfer \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> convert the default value of 500 watts to kilowatts. One kilowatt equals 1,000 watts.<\/p>\n<p>\\[500\\ \\mathrm{W}\\times\\frac{1\\ \\mathrm{W\/W}}{1{,}000\\ \\mathrm{W\/kW}}=0.5\\ \\mathrm{kW}\\]<\/p>\n<p><strong>Result:<\/strong> 500 W = 0.5 kW.<\/p>\n<p>\n\r\n<\/section>\n<h2>How to use the calculator<\/h2>\n<ol>\n<li>Enter a nonnegative number in <strong>Heat transfer rate<\/strong>. The number is interpreted in the unit you choose next; you do not need to type a unit in the field.<\/li>\n<li>Choose the unit of your entered value under <strong>From unit<\/strong>. For example, select Watt (W) if your value is in watts.<\/li>\n<li>Choose the unit you want under <strong>To unit<\/strong>. For example, select Kilowatt (kW) to express the rate in kilowatts.<\/li>\n<li>Read <strong>Converted Heat Transfer<\/strong>. The result includes the destination unit and is displayed to a maximum of eight decimal places.<\/li>\n<\/ol>\n<p>Both menus offer W, kW, MW, cal\/s, kcal\/s, BTU\/s, BTU\/min, and BTU\/h. You can convert in either direction, such as W to BTU\/h or BTU\/h to W. Selecting the same unit in both menus leaves the value unchanged.<\/p>\n<h2>What a heat transfer rate means<\/h2>\n<p>A heat transfer rate tells you how much thermal energy moves between systems per unit of time. It is commonly written as \\(\\dot Q\\). One watt is one joule per second, so a heat transfer rate of 500 W means energy is being transferred at 500 joules each second. The converter changes the unit used to express that rate; it does not change the physical amount of heat being transferred.<\/p>\n<p>Heat transfer rates appear in heating and cooling specifications, heat exchanger calculations, and assessments of heat loss through walls or equipment. They are distinct from total heat energy: a rate in W or BTU\/h does not tell you the total energy transferred unless you also know the duration. At a constant rate, multiplying the rate by time gives the transferred energy in matching units\u2014for example, W multiplied by seconds gives joules.<\/p>\n<p>A larger converted number does not necessarily mean more heat transfer. The numerical value changes with the size of the unit: 1 kW and 1,000 W describe the same rate. When comparing equipment or calculations, convert all rates to a common unit first. If you need to relate a rate to the area it crosses, use a <a href=\"https:\/\/wpcalc.com\/en\/converters\/heat-flux-density\/\">heat flux density converter<\/a>; heat flux density is a rate per unit area, not another unit of total heat transfer rate.<\/p>\n<h2>Conversion factors and practical limits<\/h2>\n<p>The calculator uses watts as its intermediate unit. The following table shows the exact factors used by the calculator, expressed as watts per listed unit. These are the factors behind every available conversion, including conversions between two non-watt units.<\/p>\n<table>\n<thead>\n<tr>\n<th>Unit<\/th>\n<th>Watts per unit<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>W<\/td>\n<td>1<\/td>\n<\/tr>\n<tr>\n<td>kW<\/td>\n<td>1,000<\/td>\n<\/tr>\n<tr>\n<td>MW<\/td>\n<td>1,000,000<\/td>\n<\/tr>\n<tr>\n<td>cal\/s<\/td>\n<td>4.184<\/td>\n<\/tr>\n<tr>\n<td>kcal\/s<\/td>\n<td>4,184<\/td>\n<\/tr>\n<tr>\n<td>BTU\/s<\/td>\n<td>1,055.06<\/td>\n<\/tr>\n<tr>\n<td>BTU\/min<\/td>\n<td>17.5843<\/td>\n<\/tr>\n<tr>\n<td>BTU\/h<\/td>\n<td>0.29307107<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The calorie factors use 1 calorie = 4.184 joules. BTU conversions depend slightly on the BTU definition and reference convention; the table states the approximate factors this calculator applies. The BTU factors are rounded independently, so a result may differ slightly from one obtained by converting between BTU time units using time alone. Display rounding can also hide small nonzero values; for high-precision work, retain more digits in your source calculation.<\/p>\n<p>The input accepts zero and positive rates, but not negative values. It therefore cannot represent direction with a sign: specify the direction of heat flow separately when that matters. This is a unit converter, not a heat-transfer model. It cannot determine a rate from temperature difference, surface area, or material properties. For those calculations, you may also need <a href=\"https:\/\/wpcalc.com\/en\/converters\/thermal-conductivity\/\">thermal conductivity<\/a> or <a href=\"https:\/\/wpcalc.com\/en\/converters\/specific-heat\/\">specific heat<\/a>, depending on the situation.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Convert a heat transfer rate between watts, kilowatts, megawatts, calories per second, and BTU-based units. Enter a rate, then select the From unit and To unit.<\/p>\n","protected":false},"author":70,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[3],"tags":[34],"class_list":["post-55826","post","type-post","status-publish","format-standard","hentry","category-converters","tag-physics-units"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55826","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/users\/70"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/comments?post=55826"}],"version-history":[{"count":2,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55826\/revisions"}],"predecessor-version":[{"id":65276,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55826\/revisions\/65276"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=55826"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=55826"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=55826"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}