{"id":65873,"date":"2026-09-30T13:56:45","date_gmt":"2026-09-30T10:56:45","guid":{"rendered":"https:\/\/wpcalc.com\/en\/?p=65873"},"modified":"2026-09-30T13:56:45","modified_gmt":"2026-09-30T10:56:45","slug":"mechanical-efficiency-calculator","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/physics\/mechanical-efficiency-calculator\/","title":{"rendered":"Mechanical Efficiency Calculator"},"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\">Find the Efficiency of a Machine or Process<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"65873\" data-favorite-title=\"Mechanical Efficiency\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/physics\/mechanical-efficiency-calculator\/\" data-favorite-excerpt=\"Enter the work, energy or power you put into a machine and what you get out of it, and this calculator returns the mechanical efficiency as a percentage plus the energy that is lost.\" 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\/physics\/mechanical-efficiency-calculator\/\" method=\"POST\" class=\"calculator\" id=\"calculator-65873\" data-post=\"65873\"><fieldset class=\"fieldset-input is-1\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field is-single\" id=\"input-1\"><label for=\"field-1\">Quantity type<\/label><div class=\"grid grid-cols-1\"><select id=\"field-1\" name=\"quantity_type\"><option value=\"energy\" selected>Work or energy (J, kWh, cal\u2026)<\/option><option value=\"power\">Power (W, kW, hp\u2026)<\/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 has-term\" id=\"input-2\"><label for=\"field-2\">Input work \/ energy (W in)<\/label><div class=\"term\">W\u1d62\u2099<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"input_work_energy_w_in\" id=\"field-2\" aria-describedby=\"calc-info-2\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"e.g. 500\" min=\"0\" value=\"500\"\/><div class=\"grid grid-cols-1\"><select id=\"field-3\" name=\"unit\" aria-label=\"Unit\"><option value=\"J\" selected>J<\/option><option value=\"kJ\">kJ<\/option><option value=\"MJ\">MJ<\/option><option value=\"cal\">cal<\/option><option value=\"kcal\">kcal<\/option><option value=\"kWh\">kWh<\/option><option value=\"ftlb\">ft\u00b7lb<\/option><option value=\"BTU\">BTU<\/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><small id=\"calc-info-2\">Work or energy supplied to the machine (the effort you put in).<\/small><\/div><div class=\"field has-term\" id=\"input-3\"><label for=\"field-4\">Output work \/ energy (W out)<\/label><div class=\"term\">W\u2092\u1d64\u209c<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"output_work_energy_w_out\" id=\"field-4\" aria-describedby=\"calc-info-4\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"e.g. 400\" min=\"0\" value=\"400\"\/><div class=\"grid grid-cols-1\"><select id=\"field-5\" name=\"unit\" aria-label=\"Unit\"><option value=\"J\" selected>J<\/option><option value=\"kJ\">kJ<\/option><option value=\"MJ\">MJ<\/option><option value=\"cal\">cal<\/option><option value=\"kcal\">kcal<\/option><option value=\"kWh\">kWh<\/option><option value=\"ftlb\">ft\u00b7lb<\/option><option value=\"BTU\">BTU<\/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><small id=\"calc-info-4\">Useful work or energy delivered by the machine (what you get out).<\/small><\/div><div class=\"field has-term\" id=\"input-4\" hidden><label for=\"field-6\">Input power (P in)<\/label><div class=\"term\">P\u1d62\u2099<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"input_power_p_in\" id=\"field-6\" aria-describedby=\"calc-info-6\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"e.g. 1500\" min=\"0\" value=\"1500\"\/><div class=\"grid grid-cols-1\"><select id=\"field-7\" name=\"unit\" aria-label=\"Unit\"><option value=\"W\" selected>W<\/option><option value=\"kW\">kW<\/option><option value=\"MW\">MW<\/option><option value=\"hp\">hp<\/option><option value=\"ftlbs\">ft\u00b7lb\/s<\/option><option value=\"BTUh\">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><small id=\"calc-info-6\">Power supplied to the machine.<\/small><\/div><div class=\"field has-term\" id=\"input-5\" hidden><label for=\"field-8\">Output power (P out)<\/label><div class=\"term\">P\u2092\u1d64\u209c<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"output_power_p_out\" id=\"field-8\" aria-describedby=\"calc-info-8\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"e.g. 1200\" min=\"0\" value=\"1200\"\/><div class=\"grid grid-cols-1\"><select id=\"field-9\" name=\"unit\" aria-label=\"Unit\"><option value=\"W\" selected>W<\/option><option value=\"kW\">kW<\/option><option value=\"MW\">MW<\/option><option value=\"hp\">hp<\/option><option value=\"ftlbs\">ft\u00b7lb\/s<\/option><option value=\"BTUh\">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><small id=\"calc-info-8\">Useful power delivered by the machine.<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"65873\">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> Mechanical Efficiency Results<\/h3><div class=\"result-box\"><div class=\"field-result is-column\" id=\"output-1\"><span class=\"field-title\"><span>Efficiency percentage<\/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 class=\"field-result is-column\" id=\"output-2\"><span class=\"field-title\"><span>Energy losses<\/span><\/span><span class=\"field-value\" id=\"result-2\"><\/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 class=\"field-result is-column\" id=\"output-3\"><span class=\"field-title\"><span>Formulas used<\/span><\/span><span class=\"field-value\" id=\"result-3\"><\/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=\"65873\" 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>Mechanical Efficiency 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\\[ \\eta = \\frac{W_{\\text{out}}}{W_{\\text{in}}} \\times 100\\,\\% \\\\ W_{\\text{loss}} = W_{\\text{in}} - W_{\\text{out}} \\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(\\eta\\) \u2014 mechanical efficiency (%)<\/li>\n<li>\\(W_{\\text{out}}\\) \u2014 useful work or energy delivered by the machine (J)<\/li>\n<li>\\(W_{\\text{in}}\\) \u2014 work or energy supplied to the machine (J)<\/li>\n<li>\\(W_{\\text{loss}}\\) \u2014 energy lost, mostly to friction and heat (J)<\/li>\n<\/ul>\n<p>The formula expresses how large a share of the input actually reaches the output. Because power is simply work per unit of time, the same ratio applies to power: \\(\\eta = P_{\\text{out}} \/ P_{\\text{in}} \\times 100\\,\\%\\).<\/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>Mechanical Efficiency \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> a small electric hoist receives 500 J of electrical energy and uses it to lift a load, doing 400 J of useful work against gravity.<\/p>\n<p>\\[ \\eta = \\frac{400\\ \\text{J}}{500\\ \\text{J}} \\times 100\\,\\% = 80\\,\\% \\]<\/p>\n<p>\\[ W_{\\text{loss}} = 500\\ \\text{J} - 400\\ \\text{J} = 100\\ \\text{J} \\]<\/p>\n<p><strong>Result:<\/strong> the efficiency is 80 %, and 100 J (20 % of the input) is lost, mainly as heat from friction in the motor and gears.<\/p>\n<p>\n\r\n<\/section>\n<h2>How to use the calculator<\/h2>\n<ol>\n<li>In <strong>Quantity type<\/strong>, choose whether you are entering <em>Work or energy<\/em> (J, kWh, cal\u2026) or <em>Power<\/em> (W, kW, hp\u2026). Only the fields for that mode are shown.<\/li>\n<li>Enter <strong>Input work \/ energy (W in)<\/strong> (or <strong>Input power (P in)<\/strong>) \u2014 the amount you supply to the machine \u2014 and pick its unit from the dropdown.<\/li>\n<li>Enter <strong>Output work \/ energy (W out)<\/strong> (or <strong>Output power (P out)<\/strong>) \u2014 the useful amount the machine delivers \u2014 and select its unit. The two units do not have to match; the calculator converts them automatically.<\/li>\n<li>Read the results: the <strong>efficiency percentage<\/strong> with a practical rating, the <strong>energy losses<\/strong> converted into several units, and the <strong>formulas used<\/strong> with your numbers substituted in.<\/li>\n<\/ol>\n<h2>What is mechanical efficiency?<\/h2>\n<p>Mechanical efficiency measures how well a machine or process converts what you put into it into useful output. No machine is perfect: part of every input is always consumed by <a href=\"https:\/\/wpcalc.com\/en\/physics\/friction-force-calculator\/\">friction<\/a> between moving parts, air resistance, deformation, vibration and noise. Efficiency compares the useful output with the total input, so it tells you at a glance what fraction of your effort \u2014 or your energy bill \u2014 is actually doing the job you want.<\/p>\n<p>An efficiency of 100 % would mean a lossless, ideal machine. Real machines always fall short of that: a typical car engine converts only about 25\u201335 % of the fuel's energy into motion, electric motors reach 85\u201395 %, and large transformers can hit 98\u201399 %. When the calculator shows a low percentage, most of the input is being turned into heat rather than useful work \u2014 which is also why machines get warm and need cooling or lubrication.<\/p>\n<p>Note that efficiency is a pure ratio, so it works identically for work, energy and power. If you measure input and output over the same period of time, the energies and the powers give exactly the same result, because power is energy divided by time \u2014 the time cancels out. This is a direct consequence of the <a href=\"https:\/\/wpcalc.com\/en\/physics\/conservation-of-energy-calculator\/\">conservation of energy<\/a>: the energy that does not appear at the output has not vanished, it has simply been converted into less useful forms.<\/p>\n<p>If you need the input and output values themselves, the <a href=\"https:\/\/wpcalc.com\/en\/physics\/work\/\">work<\/a> and <a href=\"https:\/\/wpcalc.com\/en\/physics\/power-calculator\/\">power<\/a> calculators will find them from force, distance and speed.<\/p>\n<h2>Assumptions, limitations and practical tips<\/h2>\n<ul>\n<li><strong>Input must be at least as large as output.<\/strong> The calculator rejects values where the output exceeds the input, since a real machine cannot deliver more work or power than it receives. If you see that error, the values or the units are almost certainly mixed up.<\/li>\n<li><strong>Compare the same process or time interval.<\/strong> For power values, the input and output should be measured at the same steady operating point. For energies, they must refer to the same task \u2014 for example, the same lift or the same cycle.<\/li>\n<li><strong>Mixed units are fine.<\/strong> You can enter the input in kWh and the output in J; the calculator converts everything internally (1 kWh = 3.6\u00d710\u2076 J, 1 hp = 745.7 W, 1 BTU = 1055.06 J, and so on).<\/li>\n<li><strong>Efficiency can depend on load.<\/strong> A motor or gearbox is usually most efficient near its rated load and noticeably less efficient when lightly loaded. A single number is a snapshot at one operating condition.<\/li>\n<li><strong>The losses are not useless energy \u2014 just misdirected.<\/strong> They leave the machine as heat. Reducing friction through lubrication, better bearings or smoother surfaces is usually the cheapest way to raise efficiency.<\/li>\n<li><strong>Beware of \u201cefficiency\u201d claims above 100 %.<\/strong> A ratio over 100 % would violate energy conservation. Devices such as heat pumps can deliver more heat than the electricity they consume, but that is a different quantity (coefficient of performance), not mechanical efficiency.<\/li>\n<\/ul>\n<h2>Typical efficiency ranges<\/h2>\n<table>\n<thead>\n<tr>\n<th>Machine or process<\/th>\n<th>Typical efficiency<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Large transformer<\/td>\n<td>98\u201399 %<\/td>\n<\/tr>\n<tr>\n<td>Precision gearbox<\/td>\n<td>97\u201399 %<\/td>\n<\/tr>\n<tr>\n<td>Electric motor<\/td>\n<td>85\u201395 %<\/td>\n<\/tr>\n<tr>\n<td>Bicycle chain drive<\/td>\n<td>\u2248 95 %<\/td>\n<\/tr>\n<tr>\n<td>Pulley system (several sheaves)<\/td>\n<td>70\u201390 %<\/td>\n<\/tr>\n<tr>\n<td>Car engine (fuel to motion)<\/td>\n<td>25\u201335 %<\/td>\n<\/tr>\n<tr>\n<td>Incandescent lamp (electricity to light)<\/td>\n<td>\u2248 2\u20135 %<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Use these ranges as a sanity check: if your calculated efficiency is far outside the expected band for that type of machine, re-check the measured values and their units before trusting the result.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Enter the work, energy or power you put into a machine and what you get out of it, and this calculator returns the mechanical efficiency as a percentage plus the energy that is lost.<\/p>\n","protected":false},"author":3168,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[62],"tags":[91],"class_list":["post-65873","post","type-post","status-publish","format-standard","hentry","category-physics","tag-energy-work"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/65873","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\/3168"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/comments?post=65873"}],"version-history":[{"count":1,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/65873\/revisions"}],"predecessor-version":[{"id":65926,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/65873\/revisions\/65926"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=65873"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=65873"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=65873"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}