{"id":55894,"date":"2015-10-24T15:55:06","date_gmt":"2015-10-24T13:55:06","guid":{"rendered":"http:\/\/wpcalc.com\/?p=55894"},"modified":"2026-09-28T09:34:04","modified_gmt":"2026-09-28T06:34:04","slug":"radioactivity","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/converters\/radioactivity\/","title":{"rendered":"Radioactivity 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 Radioactivity Between Units<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"55894\" data-favorite-title=\"Radioactivity\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/converters\/radioactivity\/\" data-favorite-excerpt=\"Convert radioactive activity between Bq, kBq, MBq, GBq, Ci, mCi, and \u00b5Ci. Enter an activity value, then choose the starting and target units.\" 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\/radioactivity\/\" method=\"POST\" class=\"calculator\" id=\"calculator-55894\" data-post=\"55894\"><fieldset class=\"fieldset-input\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field is-single\" id=\"input-1\"><label for=\"field-1\">Activity value<\/label><input type=\"text\" name=\"activity_value\" id=\"field-1\" aria-describedby=\"calc-unit-1 calc-info-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"1\"\/><div class=\"unit\" id=\"calc-unit-1\"><\/div><small id=\"calc-info-1\">Enter the radioactivity 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=\"Bq\">Becquerel (Bq)<\/option><option value=\"kBq\">Kilobecquerel (kBq)<\/option><option value=\"MBq\">Megabecquerel (MBq)<\/option><option value=\"GBq\">Gigabecquerel (GBq)<\/option><option value=\"Ci\">Curie (Ci)<\/option><option value=\"mCi\">Millicurie (mCi)<\/option><option value=\"\u00b5Ci\">Microcurie (\u00b5Ci)<\/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=\"Bq\">Becquerel (Bq)<\/option><option value=\"kBq\">Kilobecquerel (kBq)<\/option><option value=\"MBq\">Megabecquerel (MBq)<\/option><option value=\"GBq\">Gigabecquerel (GBq)<\/option><option value=\"Ci\">Curie (Ci)<\/option><option value=\"mCi\">Millicurie (mCi)<\/option><option value=\"\u00b5Ci\">Microcurie (\u00b5Ci)<\/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=\"55894\">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 Radioactivity<\/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=\"55894\" 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\">1<\/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>Radioactivity 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\\[ A_{\\mathrm{to}}=A_{\\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>\\(A_{\\mathrm{from}}\\) \u2014 the entered activity in the starting unit<\/li>\n<li>\\(A_{\\mathrm{to}}\\) \u2014 the converted activity in the target unit<\/li>\n<li>\\(f_{\\mathrm{from}}\\) \u2014 the number of becquerels in one starting unit<\/li>\n<li>\\(f_{\\mathrm{to}}\\) \u2014 the number of becquerels in one target unit<\/li>\n<\/ul>\n<p>The converter first expresses the entered activity in becquerels, then divides by the becquerel value of the target unit. One becquerel is one nuclear decay per second.<\/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>Radioactivity \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> enter the default Activity value of 1, then select Curie (Ci) as the From unit and Becquerel (Bq) as the To unit.<\/p>\n<p>\\[ A_{\\mathrm{to}}=1\\,\\mathrm{Ci}\\times\\frac{3.7\\times10^{10}\\,\\mathrm{Bq}}{1\\,\\mathrm{Ci}}=3.7\\times10^{10}\\,\\mathrm{Bq} \\]<\/p>\n<p><strong>Result:<\/strong> 1 Ci = 37,000,000,000 Bq.<\/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>Activity value<\/strong>. For example, enter 1 to convert one unit, or enter a measured activity to convert that reading.<\/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 Radioactivity<\/strong>. Its unit is the one selected in To unit.<\/li>\n<\/ol>\n<p>You can select the same unit in both menus to leave the value unchanged. The available units are Bq, kBq, MBq, GBq, Ci, mCi, and \u00b5Ci. The calculator does not accept negative activity values.<\/p>\n<h2>What radioactive activity measures<\/h2>\n<p>Radioactive activity is the rate at which unstable nuclei decay. A source with an activity of 1 Bq has, on average, one nuclear decay per second; 1,000 Bq is 1 kBq. Individual decays occur unpredictably, so activity describes an average rate rather than a promise that exactly that many decays will occur in every second.<\/p>\n<p>The becquerel is the SI unit of activity. The curie is an older, much larger unit: 1 Ci is exactly \\(3.7\\times10^{10}\\) Bq for unit conversion. Its subdivisions are useful for smaller activities: 1 mCi is \\(3.7\\times10^7\\) Bq, and 1 \u00b5Ci is \\(3.7\\times10^4\\) Bq. These conversions change only the unit, not the quantity of radioactive material or its decay rate.<\/p>\n<p>Activity appears on radioactive source labels and in laboratory, medical, and environmental measurements. It is not a radiation dose. Two sources with the same activity can produce different exposures because the radiation type and energy, shielding, distance, and duration differ. Activity alone therefore cannot tell you whether a source is safe or calculate a dose in sieverts.<\/p>\n<p>Becquerels and hertz both have units of reciprocal seconds, but they describe different things: Bq counts nuclear decays, while Hz describes the repetition rate of a periodic event. For periodic rates rather than radioactive activity, use the <a href=\"https:\/\/wpcalc.com\/en\/converters\/frequency\/\">frequency converter<\/a>.<\/p>\n<h2>Conversion factors<\/h2>\n<p>Each factor below gives the number of becquerels in one unit. Multiply by the factor to convert to Bq; divide by the factor to convert from Bq.<\/p>\n<table>\n<thead>\n<tr>\n<th>Unit<\/th>\n<th>Equivalent in Bq<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>1 Bq<\/td>\n<td>1 Bq<\/td>\n<\/tr>\n<tr>\n<td>1 kBq<\/td>\n<td>1,000 Bq<\/td>\n<\/tr>\n<tr>\n<td>1 MBq<\/td>\n<td>1,000,000 Bq<\/td>\n<\/tr>\n<tr>\n<td>1 GBq<\/td>\n<td>1,000,000,000 Bq<\/td>\n<\/tr>\n<tr>\n<td>1 Ci<\/td>\n<td>37,000,000,000 Bq<\/td>\n<\/tr>\n<tr>\n<td>1 mCi<\/td>\n<td>37,000,000 Bq<\/td>\n<\/tr>\n<tr>\n<td>1 \u00b5Ci<\/td>\n<td>37,000 Bq<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Assumptions and practical limits<\/h2>\n<p>This is a unit conversion, not a decay-over-time calculation. It assumes the activity being converted refers to the same source at the same time. A radioactive source\u2019s activity changes over time according to its half-life, but this converter does not ask for an isotope, a half-life, or an elapsed time.<\/p>\n<p>The result is rounded to 10 decimal places. When converting a small Bq value to Ci, the displayed result may be 0 Ci even though the activity is not zero. For example, 1 Bq is approximately \\(2.7027\\times10^{-11}\\) Ci. Choose a smaller target unit, such as \u00b5Ci, when you need a more useful displayed value.<\/p>\n<p>The calculator converts total activity, not activity concentration such as Bq per kilogram or Bq per liter. If you are working with a moving material stream, <a href=\"https:\/\/wpcalc.com\/en\/converters\/mass-flow-rate\/\">mass flow rate<\/a> is a separate measurement; converting either measurement does not determine the other. Likewise, an instrument\u2019s detected counts per second may differ from the source\u2019s decays per second because detection efficiency, geometry, and background affect the count rate.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Convert radioactive activity between Bq, kBq, MBq, GBq, Ci, mCi, and \u00b5Ci. Enter an activity value, then choose the starting and target units.<\/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-55894","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\/55894","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=55894"}],"version-history":[{"count":2,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55894\/revisions"}],"predecessor-version":[{"id":65307,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/55894\/revisions\/65307"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=55894"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=55894"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=55894"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}