{"id":55812,"date":"2015-01-19T17:14:07","date_gmt":"2015-01-19T15:14:07","guid":{"rendered":"http:\/\/wpcalc.com\/?p=55812"},"modified":"2026-09-28T09:19:35","modified_gmt":"2026-09-28T06:19:35","slug":"entropy","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/converters\/entropy\/","title":{"rendered":"Entropy Units 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\">All Entropy Units Conversion Tool<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"55812\" data-favorite-title=\"Entropy Conversions\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/converters\/entropy\/\" data-favorite-excerpt=\"Convert an entropy value between the units offered by the calculator. Enter a Value, then choose the From unit and To unit; check the notes before comparing molar with total entropy or using the BTU and eV results.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-chemistry\">\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\/entropy\/\" method=\"POST\" class=\"calculator\" id=\"calculator-55812\" data-post=\"55812\"><fieldset class=\"fieldset-input\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field is-single\" id=\"input-1\"><label for=\"field-1\">Value<\/label><input type=\"number\" name=\"value\" id=\"field-1\" aria-describedby=\"calc-info-1\" step=\"0.01\" value=\"1\"\/><small id=\"calc-info-1\">Enter the entropy value you want 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_k_mol\">J\/K\u00b7mol<\/option><option value=\"cal_k_mol\">cal\/K\u00b7mol<\/option><option value=\"j_k\">J\/K<\/option><option value=\"kj_k\">kJ\/K<\/option><option value=\"kj_k_mol\">kJ\/K\u00b7mol<\/option><option value=\"erg_k\">erg\/K<\/option><option value=\"btu_f\">BTU\/\u00b0F<\/option><option value=\"btu_k\">BTU\/K<\/option><option value=\"eV_k\">eV\/K<\/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_k_mol\">J\/K\u00b7mol<\/option><option value=\"cal_k_mol\">cal\/K\u00b7mol<\/option><option value=\"j_k\">J\/K<\/option><option value=\"kj_k\">kJ\/K<\/option><option value=\"kj_k_mol\">kJ\/K\u00b7mol<\/option><option value=\"erg_k\">erg\/K<\/option><option value=\"btu_f\">BTU\/\u00b0F<\/option><option value=\"btu_k\">BTU\/K<\/option><option value=\"eV_k\">eV\/K<\/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=\"55812\">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 Entropy<\/span><\/span><span class=\"field-value\" id=\"result-1\" data-unit=\"\"><\/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=\"55812\" 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\">1<\/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>Entropy Conversions 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\\[\\text{Converted value}=\\text{Value}\\times\\frac{f_{\\text{from}}}{f_{\\text{to}}}\\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(f_{\\text{from}}\\) \u2014 the calculator\u2019s factor for the selected From unit.<\/li>\n<li>\\(f_{\\text{to}}\\) \u2014 the calculator\u2019s factor for the selected To unit.<\/li>\n<\/ul>\n<p>The calculator multiplies the entered number by the ratio of its stored factors. This gives a valid unit conversion when the units describe the same kind of entropy and the factors match the intended unit definitions.<\/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>Entropy Conversions \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> enter the default Value of 1, keep From unit as J\/K\u00b7mol, and change To unit to cal\/K\u00b7mol. The calculator uses 1 for J\/K\u00b7mol and 4.184 for cal\/K\u00b7mol.<\/p>\n<p>\\[1\\times\\frac{1}{4.184}\\approx 0.239006\\]<\/p>\n<p><strong>Result:<\/strong> 1 J\/K\u00b7mol is approximately 0.239006 cal\/K\u00b7mol. The displayed number may be rounded.<\/p>\n<p>\n\r\n<\/section>\n<h2>How to use the calculator<\/h2>\n<ol>\n<li>Enter the number you want to convert in <strong>Value<\/strong>. A negative number can represent an entropy change, such as the difference between two states.<\/li>\n<li>Choose the unit of that number in <strong>From unit<\/strong>. Check whether it is a total entropy unit, such as J\/K, or a molar entropy unit, such as J\/K\u00b7mol.<\/li>\n<li>Choose the desired <strong>To unit<\/strong>. For a straightforward unit conversion, keep total entropy with total entropy or molar entropy with molar entropy.<\/li>\n<li>Read the number under <strong>Converted Entropy<\/strong> and label it with your selected To unit when recording the result; the result field does not add a unit automatically.<\/li>\n<\/ol>\n<h2>What entropy units mean<\/h2>\n<p>Thermodynamic entropy is a property of a system. An entropy change helps describe how a process distributes energy and is used in heat-transfer and thermodynamic calculations. Total entropy is commonly expressed in joules per kelvin (J\/K). Molar entropy divides that quantity by the amount of substance and is expressed in joules per kelvin per mole (J\/K\u00b7mol). The distinction matters: a sample\u2019s total entropy depends on how much substance is present, while its molar entropy is stated per mole.<\/p>\n<p>Changing from J\/K\u00b7mol to cal\/K\u00b7mol changes only the energy unit. Both numbers still describe entropy per mole, and the calculator uses 1 cal = 4.184 J. Likewise, changing between J\/K and kJ\/K changes the energy prefix without changing the quantity being measured. A larger numerical value in one unit does not, by itself, mean the physical entropy has increased.<\/p>\n<p>Converting between a molar unit and a total unit is different. You need the amount of substance: \\(S=nS_m\\), where \\(S\\) is total entropy, \\(S_m\\) is molar entropy, and \\(n\\) is the number of moles. This calculator has no moles field, so its output for a molar-to-total selection is only a numerical factor calculation, not a complete physical conversion. If you need to find an amount in moles first, use the <a href=\"https:\/\/wpcalc.com\/en\/converters\/moles-and-grams\/\">Moles and Grams calculator<\/a>.<\/p>\n<h2>Factors and important limitations<\/h2>\n<p>The table shows the factors used by this calculator. To reproduce its arithmetic, divide the From unit factor by the To unit factor. A factor of 1 for both J\/K\u00b7mol and J\/K does <em>not<\/em> make those units interchangeable: the mole in the denominator changes what the number represents.<\/p>\n<table>\n<thead>\n<tr>\n<th>Unit<\/th>\n<th>Calculator factor<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>J\/K\u00b7mol<\/td>\n<td>1<\/td>\n<\/tr>\n<tr>\n<td>cal\/K\u00b7mol<\/td>\n<td>4.184<\/td>\n<\/tr>\n<tr>\n<td>kJ\/K\u00b7mol<\/td>\n<td>1,000<\/td>\n<\/tr>\n<tr>\n<td>J\/K<\/td>\n<td>1<\/td>\n<\/tr>\n<tr>\n<td>kJ\/K<\/td>\n<td>1,000<\/td>\n<\/tr>\n<tr>\n<td>erg\/K<\/td>\n<td>0.0000001<\/td>\n<\/tr>\n<tr>\n<td>BTU\/\u00b0F<\/td>\n<td>5,285<\/td>\n<\/tr>\n<tr>\n<td>BTU\/K<\/td>\n<td>1,899<\/td>\n<\/tr>\n<tr>\n<td>eV\/K<\/td>\n<td>1.381 \u00d7 10\u207b\u00b2\u00b3<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><strong>Check BTU and eV conversions independently.<\/strong> The stored factors for these selections do not match standard physical unit conversions. Using 1 international table BTU \u2248 1,055.056 J, 1 BTU\/K \u2248 1,055.056 J\/K and 1 BTU\/\u00b0F \u2248 1,899.101 J\/K. Also, 1 eV\/K = 1.602176634 \u00d7 10\u207b\u00b9\u2079 J\/K, not the factor stored here. Do not rely on the calculator\u2019s BTU or eV output for work that requires physically accurate results.<\/p>\n<p>Temperature scales in entropy units describe the size of a temperature <em>interval<\/em>, not a temperature reading. A change of 1 \u00b0F equals a change of 5\/9 K; there is no offset to add when converting an entropy denominator. For temperature readings rather than intervals, use the <a href=\"https:\/\/wpcalc.com\/en\/converters\/fahrenheit\/\">Fahrenheit converter<\/a> or <a href=\"https:\/\/wpcalc.com\/en\/converters\/kelvin\/\">Kelvin converter<\/a>. Finally, these are thermodynamic units: the calculator does not convert information-theory entropy measured in bits or nats.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Convert an entropy value between the units offered by the calculator. Enter a Value, then choose the From unit and To unit; check the notes before comparing molar with total entropy or using the BTU and eV results.<\/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":[17],"class_list":["post-55812","post","type-post","status-publish","format-standard","hentry","category-converters","tag-chemistry-units"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55812","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=55812"}],"version-history":[{"count":2,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55812\/revisions"}],"predecessor-version":[{"id":65269,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55812\/revisions\/65269"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=55812"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=55812"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=55812"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}