{"id":61887,"date":"2021-05-14T11:06:34","date_gmt":"2021-05-14T09:06:34","guid":{"rendered":"https:\/\/wpcalc.com\/?p=61887"},"modified":"2026-09-30T18:19:49","modified_gmt":"2026-09-30T15:19:49","slug":"floor-space-index","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/engineering\/floor-space-index\/","title":{"rendered":"Floor Space Index (FSI) 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\">Calculate Floor Space Index from Built and Land Area<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"61887\" data-favorite-title=\"Floor Space Index (FSI)\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/engineering\/floor-space-index\/\" data-favorite-excerpt=\"Calculate the Floor Space Index (FSI), also known as Floor Area Ratio (FAR), by entering the total covered (built-up) area and the land area. A quick check for zoning compliance and development density.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-civil\">\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\/engineering\/floor-space-index\/\" method=\"POST\" class=\"calculator\" id=\"calculator-61887\" data-post=\"61887\"><fieldset class=\"fieldset-input\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field has-term\" id=\"input-1\"><label for=\"field-1\">Total Covered Area (CA)<\/label><div class=\"term\">CA<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"number\" name=\"total_covered_area_ca\" id=\"field-1\" aria-describedby=\"calc-unit-1\" step=\"0.01\" value=\"2000\"\/><div class=\"unit\" id=\"calc-unit-1\">ft\u00b2<\/div><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-2\">Total Land Area (LA)<\/label><div class=\"term\">LA<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"number\" name=\"total_land_area_la\" id=\"field-2\" aria-describedby=\"calc-unit-2\" step=\"0.01\" value=\"4000\"\/><div class=\"unit\" id=\"calc-unit-2\">ft\u00b2<\/div><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"61887\">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>Floor Space Index<\/span><span class=\"result-term\">FSI<\/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=\"61887\" 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>Floor Space Index (FSI) 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\\[ FSI = \\frac{CA}{LA} \\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(CA\\) \u2014 Total Covered Area, i.e. the sum of the built-up floor area of all floors (ft&sup2; or m&sup2;)<\/li>\n<li>\\(LA\\) \u2014 Total Land Area, i.e. the size of the plot on which the building stands (ft&sup2; or m&sup2;)<\/li>\n<\/ul>\n<p>The formula expresses the Floor Space Index as the ratio of the total built-up area to the plot area. Because both quantities use the same unit, the result is a dimensionless number.<\/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>FSI \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> a building has a total covered area of 2,000 ft&sup2; and stands on a plot of 4,000 ft&sup2;.<\/p>\n<p>\\[ FSI = \\frac{CA}{LA} = \\frac{2000}{4000} = 0.5 \\]<\/p>\n<p><strong>Result:<\/strong> the Floor Space Index is <strong>0.5<\/strong>. The built-up area is half the plot area, so only half of the permissible development would be used if the local zoning limit were FSI 1.0.<\/p>\n<p>\n\r\n<\/section>\n<h2>How to Use the FSI Calculator<\/h2>\n<ol>\n<li>Enter the <strong>Total Covered Area (CA)<\/strong> \u2014 the sum of the floor areas of all floors in the building, including each level of a multi-storey structure.<\/li>\n<li>Enter the <strong>Total Land Area (LA)<\/strong> \u2014 the full area of the plot or parcel of land.<\/li>\n<li>Click <strong>Calculate<\/strong> to display the Floor Space Index, rounded to two decimal places.<\/li>\n<\/ol>\n<p>Both inputs must use the same unit (ft&sup2;, m&sup2;, etc.); any consistent unit works because FSI is a ratio.<\/p>\n<h2>What Is the Floor Space Index?<\/h2>\n<p>The Floor Space Index (FSI), also called the Floor Area Ratio (FAR) or floor space ratio (FSR), is one of the most important tools in urban planning and zoning. It measures how intensively a piece of land is developed by comparing the total built-up area of all floors to the area of the plot itself. An FSI of 1.0 means the total floor area equals the plot area; an FSI of 2.0 means it is double the plot area; an FSI of 0.5 means only half the plot area is built up in total across all floors.<\/p>\n<p>For example, on a 4,000 ft&sup2; plot with a permitted FSI of 2.0, a developer may construct up to 8,000 ft&sup2; of total floor area. This could be a single-storey building covering the entire allowed footprint, a two-storey building covering half the plot, or any other combination \u2014 FSI regulates total buildable floor area, not the building's shape.<\/p>\n<p>Municipalities and development authorities set maximum FSI values for each zone to control density, manage infrastructure load, and preserve open space. Higher FSI is typically allowed near city centers and transit hubs, while low-density residential zones have stricter limits. FSI also influences property value: land where more floor area can be built is generally worth more.<\/p>\n<p>Interpreting your result is straightforward: if the calculated FSI is below the local limit, there is room for further development on the plot; if it exceeds the limit, the design must be scaled back unless premium FSI (purchasable extra development rights offered in some cities) is available.<\/p>\n<h2>Assumptions and Limitations<\/h2>\n<ul>\n<li><strong>Definitional differences:<\/strong> what counts as \"covered area\" varies by jurisdiction. Some regulations exclude balconies, basements, parking, stairwells, or service shafts; others include them. Always confirm which areas your local authority counts before comparing your FSI with the legal limit.<\/li>\n<li><strong>FSI is not coverage:<\/strong> FSI measures total floor area across all storeys, not the ground footprint. A building covering 50% of a plot over two floors still has an FSI of 1.0.<\/li>\n<li><strong>Setbacks and height rules apply separately:<\/strong> meeting the FSI limit does not guarantee compliance \u2014 zoning codes also impose setbacks, height caps, and open-space requirements.<\/li>\n<li><strong>Use consistent units:<\/strong> the covered and land areas must be entered in the same unit; mixing ft&sup2; and m&sup2; will give a meaningless result.<\/li>\n<\/ul>\n<p>If your project involves other site planning numbers, you may also find our <a href=\"https:\/\/wpcalc.com\/en\/engineering\/floor-tile\/\">Floor Tile Estimator<\/a>, <a href=\"https:\/\/wpcalc.com\/en\/engineering\/maximum-floor-live-load-capacity\/\">Maximum Floor Live Load Capacity Calculator<\/a>, and <a href=\"https:\/\/wpcalc.com\/en\/engineering\/number-of-paving-stones\/\">Number of Paving Stones Calculator<\/a> useful for working out materials and structural checks.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Calculate the Floor Space Index (FSI), also known as Floor Area Ratio (FAR), by entering the total covered (built-up) area and the land area. A quick check for zoning compliance and development density.<\/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":[4],"tags":[19],"class_list":["post-61887","post","type-post","status-publish","format-standard","hentry","category-engineering","tag-civil"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/61887","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=61887"}],"version-history":[{"count":3,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/61887\/revisions"}],"predecessor-version":[{"id":65972,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/61887\/revisions\/65972"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=61887"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=61887"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=61887"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}