{"id":55838,"date":"2015-10-24T16:00:05","date_gmt":"2015-10-24T14:00:05","guid":{"rendered":"http:\/\/wpcalc.com\/?p=55838"},"modified":"2026-09-28T09:27:20","modified_gmt":"2026-09-28T06:27:20","slug":"luminous-intensity","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/converters\/luminous-intensity\/","title":{"rendered":"Luminous Intensity 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 Luminous Intensity Between Units<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"55838\" data-favorite-title=\"Luminous Intensity\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/converters\/luminous-intensity\/\" data-favorite-excerpt=\"Convert luminous intensity between candela, millicandela, spherical candela, Hefner candle, and Violle. Enter a value and select the units to convert from and to.\" 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\/luminous-intensity\/\" method=\"POST\" class=\"calculator\" id=\"calculator-55838\" data-post=\"55838\"><fieldset class=\"fieldset-input\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field is-single\" id=\"input-1\"><label for=\"field-1\">Luminous intensity value<\/label><input type=\"text\" name=\"luminous_intensity_value\" id=\"field-1\" aria-describedby=\"calc-unit-1 calc-info-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"100\"\/><div class=\"unit\" id=\"calc-unit-1\"><\/div><small id=\"calc-info-1\">Enter the luminous intensity 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=\"cd\">Candela (cd)<\/option><option value=\"mcd\">Millicandela (mcd)<\/option><option value=\"scd\">Spherical candela (scd)<\/option><option value=\"hk\">Hefner candle (hk)<\/option><option value=\"vi\">Violle (vi)<\/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=\"cd\">Candela (cd)<\/option><option value=\"mcd\">Millicandela (mcd)<\/option><option value=\"scd\">Spherical candela (scd)<\/option><option value=\"hk\">Hefner candle (hk)<\/option><option value=\"vi\">Violle (vi)<\/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=\"55838\">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 Luminous Intensity<\/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=\"55838\" 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>Luminous Intensity Conversion 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\\[ I_{\\mathrm{to}}=I_{\\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>\\(I_{\\mathrm{from}}\\) \u2014 luminous intensity entered in the selected From unit<\/li>\n<li>\\(I_{\\mathrm{to}}\\) \u2014 luminous intensity in the selected To unit<\/li>\n<li>\\(f_{\\mathrm{from}}\\) and \\(f_{\\mathrm{to}}\\) \u2014 the number of candelas represented by one of each selected unit<\/li>\n<\/ul>\n<p>The calculator first expresses the entered value in candelas, then divides by the candela value of the target unit. Both factors must use the same candela reference.<\/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>Luminous Intensity \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> convert the default value of 100 candela (cd) to millicandela (mcd). One candela equals 1,000 millicandela, so the factors are 1 cd per cd and 0.001 cd per mcd.<\/p>\n<p>\\[ I_{\\mathrm{to}}=100\\,\\mathrm{cd}\\times\\frac{1\\,\\mathrm{cd\/cd}}{0.001\\,\\mathrm{cd\/mcd}}=100{,}000\\,\\mathrm{mcd} \\]<\/p>\n<p><strong>Result:<\/strong> 100 cd = 100,000 mcd.<\/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>Luminous intensity value<\/strong>. Use the value as stated in a lamp, LED, or other light-source specification.<\/li>\n<li>Choose its current unit in <strong>From unit<\/strong>.<\/li>\n<li>Choose the unit you need in <strong>To unit<\/strong>.<\/li>\n<li>Read <strong>Converted Luminous Intensity<\/strong>. The result includes the abbreviation of the selected target unit.<\/li>\n<\/ol>\n<p>The default settings convert 100 cd to mcd. If you select the same unit in both menus, the numerical value remains unchanged. The displayed result is rounded to up to six decimal places, so very small converted values may appear as zero.<\/p>\n<h2>What luminous intensity means<\/h2>\n<p>Luminous intensity describes how much visible light a source sends in a particular direction per unit of solid angle. Its SI unit is the <strong>candela (cd)<\/strong>. Because it is directional, a source can have different intensity values at different viewing angles. For example, a focused beam may have a high intensity along its centerline without emitting the same amount of light in every direction.<\/p>\n<p>A conversion changes only the unit used to report an intensity. It does not change the direction being measured or provide a complete picture of the source\u2019s light output. When comparing two specifications, check whether they refer to the same measurement direction. A peak intensity and an average intensity over a range of directions may describe the same product but answer different questions.<\/p>\n<p>Luminous intensity is not the same as luminous flux, illuminance, or luminance. Luminous flux, measured in lumens, describes light output across directions; illuminance describes light arriving on a surface; and luminance describes the apparent brightness of a surface in a direction. If you are working with light on a surface, use the <a href=\"https:\/\/wpcalc.com\/en\/converters\/light-illumination\/\">Light Illumination converter<\/a>. For surface luminance units, use the <a href=\"https:\/\/wpcalc.com\/en\/converters\/light-luminance\/\">Light Luminance converter<\/a>.<\/p>\n<h2>Unit factors and practical limits<\/h2>\n<p>The converter uses the following factors. Each factor is the number of candelas assigned to one unit in this calculator:<\/p>\n<table>\n<thead>\n<tr>\n<th>Unit<\/th>\n<th>Abbreviation<\/th>\n<th>Candelas per unit<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Candela<\/td>\n<td>cd<\/td>\n<td>1<\/td>\n<\/tr>\n<tr>\n<td>Millicandela<\/td>\n<td>mcd<\/td>\n<td>0.001<\/td>\n<\/tr>\n<tr>\n<td>Spherical candela<\/td>\n<td>scd<\/td>\n<td>1.0187 (approximate)<\/td>\n<\/tr>\n<tr>\n<td>Hefner candle<\/td>\n<td>hk<\/td>\n<td>0.903<\/td>\n<\/tr>\n<tr>\n<td>Violle<\/td>\n<td>vi<\/td>\n<td>19.22 (approximate)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The historical-unit factors, particularly those for spherical candela and Violle, are approximate values used by this calculator. Check the definition and conversion factor required by your source or standard before using a historical-unit result in a technical document. Candlepower (cp) and candela per steradian (cd\/sr) are not selectable units here; do not treat them as alternative labels for the units in the menus.<\/p>\n<p>Unit conversion alone cannot determine beam angle, total lumens, or brightness at a surface. Those quantities need additional information about how light is distributed or how far the surface is from the source. If you have a luminous-flux value and need to compare lumens with electrical watts under specified assumptions, see the <a href=\"https:\/\/wpcalc.com\/en\/converters\/lumens-to-watts\/\">Lumens to Watts calculator<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Convert luminous intensity between candela, millicandela, spherical candela, Hefner candle, and Violle. Enter a value and select the units to convert from and to.<\/p>\n","protected":false},"author":70,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[3],"tags":[34],"class_list":["post-55838","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\/55838","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=55838"}],"version-history":[{"count":2,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55838\/revisions"}],"predecessor-version":[{"id":65288,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55838\/revisions\/65288"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=55838"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=55838"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=55838"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}