{"id":55785,"date":"2015-10-08T15:20:37","date_gmt":"2015-10-08T13:20:37","guid":{"rendered":"http:\/\/wpcalc.com\/?p=55785"},"modified":"2026-09-28T09:11:50","modified_gmt":"2026-09-28T06:11:50","slug":"calorific-value","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/converters\/calorific-value\/","title":{"rendered":"Calorific Value 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 Calorific Values Between Energy Units<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"55785\" data-favorite-title=\"Calorific Value\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/converters\/calorific-value\/\" data-favorite-excerpt=\"Convert a calorific value between MJ\/kg, kcal\/kg, BTU\/lb, and kJ\/kg by entering a value and choosing the source and target units. Note: the calculator currently reverses conversions between different units.\" 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\/calorific-value\/\" method=\"POST\" class=\"calculator\" id=\"calculator-55785\" data-post=\"55785\"><fieldset class=\"fieldset-input\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field is-single\" id=\"input-1\"><label for=\"field-1\">Calorific value<\/label><input type=\"text\" name=\"calorific_value\" id=\"field-1\" aria-describedby=\"calc-unit-1 calc-info-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"42\"\/><div class=\"unit\" id=\"calc-unit-1\"><\/div><small id=\"calc-info-1\">Enter the calorific 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=\"MJ\/kg\">MJ\/kg<\/option><option value=\"kcal\/kg\">kcal\/kg<\/option><option value=\"BTU\/lb\">BTU\/lb<\/option><option value=\"kJ\/kg\">kJ\/kg<\/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=\"MJ\/kg\">MJ\/kg<\/option><option value=\"kcal\/kg\">kcal\/kg<\/option><option value=\"BTU\/lb\">BTU\/lb<\/option><option value=\"kJ\/kg\">kJ\/kg<\/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=\"55785\">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 Calorific Value<\/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=\"55785\" 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\">1<\/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\">2<\/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\">3<\/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>Calorific Value Converter 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\\[H_{\\mathrm{displayed}}=H_{\\mathrm{input}}\\times\\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>\\(H_{\\mathrm{input}}\\) \u2014 the number entered in the Calorific value field.<\/li>\n<li>\\(f_{\\mathrm{from}}\\) \u2014 the calculator\u2019s factor for the selected From unit.<\/li>\n<li>\\(f_{\\mathrm{to}}\\) \u2014 the calculator\u2019s factor for the selected To unit.<\/li>\n<li>\\(H_{\\mathrm{displayed}}\\) \u2014 the number shown under Converted Calorific Value.<\/li>\n<\/ul>\n<p>The calculator uses factors of 1 for MJ\/kg, 238.8459 for kcal\/kg, 429.923 for BTU\/lb, and 1,000 for kJ\/kg. <strong>Important:<\/strong> it divides by the target factor, reversing the conversion needed for a physically correct result when the units differ.<\/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>Calorific Value Converter \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> enter the default Calorific value of 42, with MJ\/kg as the From unit and kcal\/kg as the To unit.<\/p>\n<p>\\[H_{\\mathrm{displayed}}=42\\times\\frac{1}{238.8459}\\approx 0.1758\\]<\/p>\n<p><strong>Result:<\/strong> the calculator displays 0.1758 kcal\/kg. This is not the correct conversion: 42 MJ\/kg is approximately \\(42\\times238.8459=10{,}031.5278\\) kcal\/kg.<\/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>Calorific value<\/strong>. Use a value expressed in the unit you will select next.<\/li>\n<li>Choose the input unit in <strong>From unit<\/strong>: MJ\/kg, kcal\/kg, BTU\/lb, or kJ\/kg.<\/li>\n<li>Choose the desired output unit in <strong>To unit<\/strong>. Read the number and unit under <strong>Converted Calorific Value<\/strong>.<\/li>\n<li>If the two units differ, check the result before using it: the calculator\u2019s current conversion direction is reversed. The correct conversion is described below.<\/li>\n<\/ol>\n<h2>What calorific value means<\/h2>\n<p>Calorific value, also called heating value, describes the energy released by a fuel per unit of mass under specified conditions. A value in MJ\/kg or kcal\/kg lets you compare the energy content of fuels such as coal, wood, or liquid fuels on a mass basis. For example, a fuel rated at 42 MJ\/kg represents 42 megajoules of energy per kilogram according to the stated heating-value definition.<\/p>\n<p>MJ\/kg, kJ\/kg, kcal\/kg, and BTU\/lb all express energy per mass. Changing between them changes the number and unit, not the underlying energy content. A larger number after conversion does not mean the fuel has become more energetic. When both unit selectors match, the calculator correctly returns the entered number unchanged.<\/p>\n<p>Heating values are commonly reported as either higher heating value (HHV) or lower heating value (LHV). They treat the energy associated with water produced during combustion differently, so they can give different figures for the same fuel. A unit conversion cannot change HHV into LHV. Keep that distinction consistent when comparing specifications or estimating energy supplied by a known mass of fuel.<\/p>\n<h2>Conversion factors and an important limitation<\/h2>\n<p>For a physically correct conversion, first express the input in MJ\/kg, then express that quantity in the target unit. Using the calculator\u2019s rounded factors, the required relationship is \\(H_{\\mathrm{correct}}=H_{\\mathrm{input}}\\times f_{\\mathrm{to}}\/f_{\\mathrm{from}}\\). The calculator currently uses the inverse ratio. Its output is therefore unreliable whenever From unit and To unit are different; rounding the displayed answer cannot fix that error.<\/p>\n<table>\n<thead>\n<tr>\n<th>Unit<\/th>\n<th>Approximate equivalent of 1 MJ\/kg<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>MJ\/kg<\/td>\n<td>1 MJ\/kg<\/td>\n<\/tr>\n<tr>\n<td>kJ\/kg<\/td>\n<td>1,000 kJ\/kg<\/td>\n<\/tr>\n<tr>\n<td>kcal\/kg<\/td>\n<td>238.8459 kcal\/kg<\/td>\n<\/tr>\n<tr>\n<td>BTU\/lb<\/td>\n<td>429.923 BTU\/lb<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>To check a conversion manually, divide the input number by its unit\u2019s factor in the table, then multiply by the target unit\u2019s factor. For instance, 42 MJ\/kg is 42,000 kJ\/kg. The listed kcal\/kg and BTU\/lb factors are rounded, so checked results may differ slightly from conversions made with more precise constants.<\/p>\n<p>This tool accepts <strong>kJ\/kg<\/strong>, not kJ\/g. Those units differ by a factor of 1,000: 1 kJ\/g equals 1,000 kJ\/kg. Also, kcal\/kg here means kilocalories per kilogram, not the total calories in a serving of food. If you need to estimate energy for a particular mass, multiply a correctly converted energy-per-mass value by that mass, using matching mass units.<\/p>\n<p>For related calculations, a <a href=\"https:\/\/wpcalc.com\/en\/converters\/specific-heat\/\">specific heat converter<\/a> concerns energy required for a temperature change, rather than energy released by combustion. The <a href=\"https:\/\/wpcalc.com\/en\/converters\/heat-transfer\/\">heat transfer converter<\/a> and <a href=\"https:\/\/wpcalc.com\/en\/converters\/heat-flux-density\/\">heat flux density converter<\/a> address different ways of describing how thermal energy moves.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Convert a calorific value between MJ\/kg, kcal\/kg, BTU\/lb, and kJ\/kg by entering a value and choosing the source and target units. Note: the calculator currently reverses conversions between different units.<\/p>\n","protected":false},"author":70,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[3],"tags":[34],"class_list":["post-55785","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\/55785","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=55785"}],"version-history":[{"count":3,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55785\/revisions"}],"predecessor-version":[{"id":65251,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55785\/revisions\/65251"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=55785"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=55785"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=55785"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}