{"id":66766,"date":"2026-10-13T08:57:20","date_gmt":"2026-10-13T05:57:20","guid":{"rendered":"https:\/\/wpcalc.com\/en\/?p=66766"},"modified":"2026-10-13T08:57:20","modified_gmt":"2026-10-13T05:57:20","slug":"air-density-calculator","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/converters\/air-density-calculator\/","title":{"rendered":"Air Density 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 Density of Air from Temperature, Pressure and Humidity<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"66766\" data-favorite-title=\"Air Density\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/converters\/air-density-calculator\/\" data-favorite-excerpt=\"Calculate the density of air in kg\/m\u00b3, lb\/ft\u00b3 and other units from temperature, pressure and relative humidity. Enter the values and get partial pressures, molar mass and virtual temperature too.\" 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\/air-density-calculator\/\" method=\"POST\" class=\"calculator\" id=\"calculator-66766\" data-post=\"66766\"><fieldset class=\"fieldset-input is-1\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field has-term\" id=\"input-1\"><label for=\"field-1\">Air temperature (T)<\/label><div class=\"term\">T<\/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=\"number\" name=\"air_temperature_t\" id=\"field-1\" aria-describedby=\"calc-info-1\" placeholder=\"e.g. 20\" min=\"-100\" max=\"200\" step=\"any\" value=\"20\"\/><div class=\"grid grid-cols-1\"><select id=\"field-2\" name=\"unit\" aria-label=\"Unit\"><option value=\"c\" selected>\u00b0C<\/option><option value=\"f\">\u00b0F<\/option><option value=\"k\">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><small id=\"calc-info-1\">Temperature of the air. Standard atmosphere is 15 \u00b0C (59 \u00b0F).<\/small><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-3\">Atmospheric pressure (p)<\/label><div class=\"term\">p<\/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=\"atmospheric_pressure_p\" id=\"field-3\" aria-describedby=\"calc-info-3\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"e.g. 1013.25\" min=\"0\" value=\"1013.25\"\/><div class=\"grid grid-cols-1\"><select id=\"field-4\" name=\"unit\" aria-label=\"Unit\"><option value=\"hpa\" selected>hPa<\/option><option value=\"kpa\">kPa<\/option><option value=\"atm\">atm<\/option><option value=\"inhg\">inHg<\/option><option value=\"mmhg\">mmHg<\/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-3\">Barometric pressure. Standard sea-level pressure is 1013.25 hPa (29.92 inHg).<\/small><\/div><div class=\"field has-term\" id=\"input-3\"><label for=\"field-5\">Relative humidity (RH)<\/label><div class=\"term\">RH<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"relative_humidity_rh\" id=\"field-5\" aria-describedby=\"calc-unit-5 calc-info-5\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"e.g. 50\" min=\"0\" max=\"100\" value=\"50\"\/><div class=\"unit\" id=\"calc-unit-5\">%<\/div><small id=\"calc-info-5\">Humid air is slightly less dense than dry air. Leave blank or enter 0 for dry air.<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"66766\">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> Air Density Results<\/h3><div class=\"result-box\"><div class=\"field-result is-column\" id=\"output-1\"><span class=\"field-title\"><span>Air density (\u03c1)<\/span><span class=\"result-term\">\u03c1<\/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>Moist air details \u2014 partial pressures and composition<\/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><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=\"66766\" 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>Air Density 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\\[ \\rho = \\frac{p_d}{R_d \\, T} + \\frac{p_v}{R_v \\, T}, \\qquad p_v = \\frac{RH}{100}\\, e_s(T), \\qquad p_d = p - p_v \\\\ e_s(T) = 6.112\\,\\exp\\!\\left(\\frac{17.62\\,T}{243.12 + T}\\right) \\]<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(\\rho\\) \u2014 density of the moist air (kg\/m\u00b3)<\/li>\n<li>\\(p\\) \u2014 total atmospheric pressure (converted to Pa)<\/li>\n<li>\\(p_d\\) \u2014 partial pressure of the dry air (Pa)<\/li>\n<li>\\(p_v\\) \u2014 partial pressure of the water vapour (Pa)<\/li>\n<li>\\(T\\) \u2014 absolute temperature (K)<\/li>\n<li>\\(RH\\) \u2014 relative humidity (%)<\/li>\n<li>\\(e_s(T)\\) \u2014 saturation vapour pressure over water (hPa), from the Magnus formula with \\(T\\) in \u00b0C<\/li>\n<li>\\(R_d = 287.058\\) J\/(kg\u00b7K) \u2014 specific gas constant of dry air<\/li>\n<li>\\(R_v = 461.495\\) J\/(kg\u00b7K) \u2014 specific gas constant of water vapour<\/li>\n<\/ul>\n<p>The formula treats moist air as an ideal mixture of dry air and water vapour: each component contributes its own density according to the ideal gas law, using its own partial pressure and gas constant.<\/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>Air Density \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> air at 20 \u00b0C, standard sea-level pressure of 1013.25 hPa and 50 % relative humidity (the calculator's default values).<\/p>\n<p>\\[ e_s = 6.112\\,\\exp\\!\\left(\\frac{17.62 \\times 20}{243.12 + 20}\\right) = 23.33\\ \\text{hPa} \\\\ p_v = 0.50 \\times 23.33 = 11.66\\ \\text{hPa}, \\quad p_d = 1013.25 - 11.66 = 1001.59\\ \\text{hPa} \\\\ T = 20 + 273.15 = 293.15\\ \\text{K} \\\\ \\rho = \\frac{100159}{287.058 \\times 293.15} + \\frac{1166}{461.495 \\times 293.15} = 1.1904 + 0.0086 \\]<\/p>\n<p><strong>Result:<\/strong> the air density is \\(\\rho \\approx 1.1991\\) kg\/m\u00b3 (about 0.07486 lb\/ft\u00b3). Completely dry air at the same temperature and pressure would weigh 1.2041 kg\/m\u00b3, so the humidity makes this air about 0.42 % lighter.<\/p>\n<p>\n\r\n<\/section>\n<h2>How to use the calculator<\/h2>\n<ol>\n<li>Enter the <strong>Air temperature (T)<\/strong> and pick its unit: \u00b0C, \u00b0F or K.<\/li>\n<li>Enter the <strong>Atmospheric pressure (p)<\/strong> and choose its unit: hPa, kPa, atm, inHg or mmHg. For standard sea-level conditions use 1013.25 hPa.<\/li>\n<li>Enter the <strong>Relative humidity (RH)<\/strong> in percent. Leave this field blank or enter 0 to compute dry air.<\/li>\n<li>Read the <strong>Air density (\u03c1)<\/strong> in kg\/m\u00b3, g\/L, lb\/ft\u00b3, lb\/in\u00b3 and oz\/ft\u00b3, plus a comparison with dry air at the same conditions.<\/li>\n<li>Check the <strong>Moist air details<\/strong> table for the partial pressures, saturation vapour pressure, molar mass and virtual temperature.<\/li>\n<\/ol>\n<h2>What is air density and why does it vary?<\/h2>\n<p>Air density is the mass per unit volume of air, usually expressed in kilograms per cubic metre. Despite feeling weightless, a cubic metre of air at room temperature and sea-level pressure has a mass of about 1.2 kg. Density is not a fixed constant: it depends on temperature, pressure and humidity, and it changes constantly with the weather and with altitude.<\/p>\n<p>The ideal gas law explains the two main effects. When pressure rises, molecules are pushed closer together and the air becomes denser. When temperature rises, the air expands and the same volume contains less mass, so hot air is less dense than cold air \u2014 the reason hot-air balloons rise and cold air sinks near the ground on winter nights.<\/p>\n<p>Humidity works in the opposite direction to what many people expect: <em>humid air is lighter than dry air<\/em>. A molecule of water vapour (molar mass 18.0 g\/mol) replaces heavier nitrogen and oxygen molecules (average 28.96 g\/mol) in the mixture, so at the same pressure and temperature moist air has a lower density. At 30 \u00b0C and 100 % humidity the effect reaches roughly 1.5 %, which is small but measurable with precise instruments.<\/p>\n<p>The result matters in many fields: aeronautics (lift, take-off distance, engine performance), motorsport and cycling (aerodynamic drag), ballistics, HVAC design, meteorology and the calibration of flow meters. Pilots, for example, use <em>density altitude<\/em> to quantify how much performance they lose on a hot day at a high-elevation airport.<\/p>\n<h2>Assumptions, limitations and practical tips<\/h2>\n<ul>\n<li><strong>Model:<\/strong> air is treated as an ideal-gas mixture of dry air and water vapour (a simplified CIPM-2007 approach). This is accurate to well under 0.5 % for everyday temperatures and pressures.<\/li>\n<li><strong>Water vapour curve:<\/strong> the Magnus formula is used for saturation vapour pressure; it is accurate to about 0.2 % between roughly \u221245 \u00b0C and +60 \u00b0C. Above 100 \u00b0C at sea-level pressure, or near the dew point at very high humidity, results become less reliable.<\/li>\n<li><strong>Pressure input:<\/strong> enter the actual (station) pressure, not the pressure reduced to sea level that weather reports usually quote. If you only have a sea-level value and you are at altitude, the result will be too high \u2014 pressure drops by about 12 hPa per 100 m near sea level.<\/li>\n<li><strong>Other gases:<\/strong> the composition of dry air is assumed constant and CO\u2082 variations or pollution are neglected.<\/li>\n<li><strong>Use in unit conversions:<\/strong> once you have the density, our <a href=\"https:\/\/wpcalc.com\/en\/converters\/density-units-converter\/\">Density Converter<\/a> can translate it into any other density unit.<\/li>\n<\/ul>\n<h2>Related weather and air calculations<\/h2>\n<p>Relative humidity strongly influences how the air feels and how it behaves. To go deeper into the moisture side of the calculation, try the <a href=\"https:\/\/wpcalc.com\/en\/converters\/dew-point-calculator\/\">Dew Point Calculator<\/a> or the <a href=\"https:\/\/wpcalc.com\/en\/converters\/heat-index-calculator\/\">Heat Index Calculator<\/a>, which combine temperature and humidity to describe comfort. For the cold end of the scale, the <a href=\"https:\/\/wpcalc.com\/en\/converters\/wind-chill-calculator\/\">Wind Chill Calculator<\/a> estimates how cold the air feels when wind is factored in.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Calculate the density of air in kg\/m\u00b3, lb\/ft\u00b3 and other units from temperature, pressure and relative humidity. Enter the values and get partial pressures, molar mass and virtual temperature too.<\/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":[3],"tags":[34],"class_list":["post-66766","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\/66766","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=66766"}],"version-history":[{"count":1,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/66766\/revisions"}],"predecessor-version":[{"id":66767,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/66766\/revisions\/66767"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=66766"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=66766"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=66766"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}