{"id":55810,"date":"2015-01-19T14:14:46","date_gmt":"2015-01-19T12:14:46","guid":{"rendered":"http:\/\/wpcalc.com\/?p=55810"},"modified":"2026-09-28T09:18:55","modified_gmt":"2026-09-28T06:18:55","slug":"energy","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/converters\/energy\/","title":{"rendered":"Energy 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 Energy Units Across Systems<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"55810\" data-favorite-title=\"Energy\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/converters\/energy\/\" data-favorite-excerpt=\"Convert an energy value between joules, calories, kilowatt-hours, BTUs, and other units. Enter a value, then choose 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\/energy\/\" method=\"POST\" class=\"calculator\" id=\"calculator-55810\" data-post=\"55810\"><fieldset class=\"fieldset-input\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field is-single\" id=\"input-1\"><label for=\"field-1\">Energy value<\/label><input type=\"text\" name=\"energy_value\" id=\"field-1\" aria-describedby=\"calc-unit-1 calc-info-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"1000\"\/><div class=\"unit\" id=\"calc-unit-1\"><\/div><small id=\"calc-info-1\">Enter the energy 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=\"J\">Joule (J)<\/option><option value=\"kJ\">Kilojoule (kJ)<\/option><option value=\"MJ\">Megajoule (MJ)<\/option><option value=\"cal\">Calorie (cal)<\/option><option value=\"kcal\">Kilocalorie (kcal)<\/option><option value=\"Wh\">Watt-hour (Wh)<\/option><option value=\"kWh\">Kilowatt-hour (kWh)<\/option><option value=\"eV\">Electronvolt (eV)<\/option><option value=\"BTU\">BTU (British Thermal Unit)<\/option><option value=\"erg\">Erg<\/option><option value=\"ft\u00b7lb\">Foot-pound (ft\u00b7lb)<\/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=\"J\">Joule (J)<\/option><option value=\"kJ\">Kilojoule (kJ)<\/option><option value=\"MJ\">Megajoule (MJ)<\/option><option value=\"cal\">Calorie (cal)<\/option><option value=\"kcal\">Kilocalorie (kcal)<\/option><option value=\"Wh\">Watt-hour (Wh)<\/option><option value=\"kWh\">Kilowatt-hour (kWh)<\/option><option value=\"eV\">Electronvolt (eV)<\/option><option value=\"BTU\">BTU (British Thermal Unit)<\/option><option value=\"erg\">Erg<\/option><option value=\"ft\u00b7lb\">Foot-pound (ft\u00b7lb)<\/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=\"55810\">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 Energy 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=\"55810\" 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\">0<\/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>Energy 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\\[ E_{\\mathrm{to}}=E_{\\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>\\(E_{\\mathrm{from}}\\) \u2014 the energy value entered in the From unit<\/li>\n<li>\\(E_{\\mathrm{to}}\\) \u2014 the converted energy value in the To unit<\/li>\n<li>\\(f_{\\mathrm{from}}\\) \u2014 joules per From unit<\/li>\n<li>\\(f_{\\mathrm{to}}\\) \u2014 joules per To unit<\/li>\n<\/ul>\n<p>The converter first expresses the entered value in joules, then divides by the number of joules in one target unit. This changes the unit without changing the amount of energy.<\/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>Energy \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> With the default settings, convert 1000 joules to kilocalories. One kilocalorie equals 4184 joules.<\/p>\n<p>\\[ 1000\\ \\mathrm{J}\\times\\frac{1\\ \\mathrm{J\/J}}{4184\\ \\mathrm{J\/kcal}}=0.2390057361\\ \\mathrm{kcal} \\]<\/p>\n<p><strong>Result:<\/strong> 1000 J is approximately 0.2390057361 kcal.<\/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>Energy value<\/strong>. You can use a decimal value.<\/li>\n<li>Choose the unit of that number in <strong>From unit<\/strong>.<\/li>\n<li>Choose the unit you need in <strong>To unit<\/strong>.<\/li>\n<li>Read <strong>Converted Energy Value<\/strong>. To reverse a conversion, exchange the From unit and To unit and enter the value you want to convert.<\/li>\n<\/ol>\n<p>The default fields are set to 1000, Joule (J), and Kilocalorie (kcal), matching the worked example above. Selecting the same unit in both menus leaves the numerical value unchanged.<\/p>\n<h2>What energy units mean<\/h2>\n<p>Energy is a quantity used to describe work, heat, and other physical processes. The joule (J) is the SI unit of energy, but other units are convenient at different scales. Kilojoules and megajoules express larger quantities without long strings of digits; watt-hours and kilowatt-hours are common for electrical energy; and electronvolts are useful for energies at the atomic scale.<\/p>\n<p>Calories and kilocalories are often used for heat and food energy. In this converter, one calorie (cal) equals 4.184 J, and one kilocalorie (kcal) equals 1000 cal, or 4184 J. A food-label \u201cCalorie\u201d with a capital C generally means a kilocalorie, not the smaller calorie. Choosing cal instead of kcal changes the displayed number by a factor of 1000.<\/p>\n<p>A conversion tells you how the same energy quantity is written in another unit; it does not tell you how efficiently energy is transferred or used. For example, converting kWh to J does not establish how much useful heat an appliance delivers. That depends on the process or equipment involved. A foot-pound here means a foot-pound of energy; the same unit name can also appear in discussions of <a href=\"https:\/\/wpcalc.com\/en\/converters\/torque\/\">torque<\/a>, which is a different physical quantity.<\/p>\n<h2>Conversion factors used<\/h2>\n<p>The calculator uses the following number of joules per unit. For any pair of units, multiply the entered value by the From-unit factor and divide by the To-unit factor.<\/p>\n<table>\n<thead>\n<tr>\n<th>Unit<\/th>\n<th>Joules per unit<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Joule (J)<\/td>\n<td>1<\/td>\n<\/tr>\n<tr>\n<td>Kilojoule (kJ)<\/td>\n<td>1000<\/td>\n<\/tr>\n<tr>\n<td>Megajoule (MJ)<\/td>\n<td>1,000,000<\/td>\n<\/tr>\n<tr>\n<td>Calorie (cal)<\/td>\n<td>4.184<\/td>\n<\/tr>\n<tr>\n<td>Kilocalorie (kcal)<\/td>\n<td>4184<\/td>\n<\/tr>\n<tr>\n<td>Watt-hour (Wh)<\/td>\n<td>3600<\/td>\n<\/tr>\n<tr>\n<td>Kilowatt-hour (kWh)<\/td>\n<td>3,600,000<\/td>\n<\/tr>\n<tr>\n<td>Electronvolt (eV)<\/td>\n<td>\\(1.602176634\\times10^{-19}\\)<\/td>\n<\/tr>\n<tr>\n<td>BTU (British Thermal Unit)<\/td>\n<td>1055.05585<\/td>\n<\/tr>\n<tr>\n<td>Erg<\/td>\n<td>\\(1\\times10^{-7}\\)<\/td>\n<\/tr>\n<tr>\n<td>Foot-pound (ft\u00b7lb)<\/td>\n<td>1.3558179483<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Assumptions and practical tips<\/h2>\n<p>The converter uses fixed factors, including 1055.05585 J per BTU. BTU definitions can vary slightly by convention, so a source using a different definition may produce a slightly different result. For calculations requiring a specified BTU convention, check which factor that source uses.<\/p>\n<p>The result is rounded for display to 10 decimal places. Very small results may therefore appear as zero, especially when converting from electronvolts or ergs to a much larger unit. Try a smaller target unit to see a more useful number. The number of displayed digits should not be taken as a guarantee that the original measurement was equally precise.<\/p>\n<p>Use this converter when you already know an energy quantity and only need to change its unit. If you first need to calculate energy transferred as heat, use the <a href=\"https:\/\/wpcalc.com\/en\/converters\/heat-transfer\/\">heat transfer calculator<\/a>. For a material\u2019s heat capacity per unit mass, see the <a href=\"https:\/\/wpcalc.com\/en\/converters\/specific-heat\/\">specific heat calculator<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Convert an energy value between joules, calories, kilowatt-hours, BTUs, and other units. Enter a value, then choose the From unit and To unit.<\/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-55810","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\/55810","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=55810"}],"version-history":[{"count":2,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55810\/revisions"}],"predecessor-version":[{"id":65268,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55810\/revisions\/65268"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=55810"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=55810"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=55810"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}