{"id":59382,"date":"2016-03-17T16:10:12","date_gmt":"2016-03-17T14:10:12","guid":{"rendered":"http:\/\/wpcalc.com\/?p=59382"},"modified":"2026-10-23T17:04:09","modified_gmt":"2026-10-23T14:04:09","slug":"block-wall","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/engineering\/block-wall\/","title":{"rendered":"Concrete Block Calculator \u2013 Blocks for a Wall"},"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 Number of Blocks Needed for Construction<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"59382\" data-favorite-title=\"Number of Concrete Blocks\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/engineering\/block-wall\/\" data-favorite-excerpt=\"Estimate how many concrete blocks you need for a wall. Enter the block dimensions in mm and the wall height and width in metres \u2014 the calculator divides the wall area by the block area and rounds up to the next whole block.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-engineering\">\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\/block-wall\/\" method=\"POST\" class=\"calculator\" id=\"calculator-59382\" data-post=\"59382\"><fieldset class=\"fieldset-input is-2\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field is-single\" id=\"input-1\"><label for=\"field-1\">Block size<\/label><div class=\"grid grid-cols-1\"><select id=\"field-1\" name=\"block_size\"><option value=\"cmu8\">8\u00d78\u00d716 in CMU (standard, 7\u215d\u00d715\u215d in actual)<\/option><option value=\"cmu6\">6\u00d78\u00d716 in CMU<\/option><option value=\"cmu12\">12\u00d78\u00d716 in CMU<\/option><option value=\"cmu4\">4\u00d78\u00d716 in CMU<\/option><option value=\"metric\" selected>200\u00d7200\u00d7400 mm (190\u00d7390 mm actual + 10 mm joint)<\/option><option value=\"uk\">440\u00d7215 mm (UK standard block + 10 mm joint)<\/option><option value=\"custom\">Custom block size<\/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\" hidden><label for=\"field-2\">Block height<\/label><div class=\"term\">bh<\/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=\"block_height\" id=\"field-2\" aria-describedby=\"calc-info-2\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"190\"\/><div class=\"grid grid-cols-1\"><select id=\"field-3\" name=\"block_height_unit\" aria-label=\"Block height unit\"><option value=\"mm\">mm<\/option><option value=\"cm\">cm<\/option><option value=\"in\">in<\/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\">Actual size of the block, without the joint<\/small><\/div><div class=\"field has-term\" id=\"input-3\" hidden><label for=\"field-4\">Block width<\/label><div class=\"term\">bw<\/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=\"block_width\" id=\"field-4\" aria-describedby=\"calc-info-4\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"390\"\/><div class=\"grid grid-cols-1\"><select id=\"field-5\" name=\"block_width_unit\" aria-label=\"Block width unit\"><option value=\"mm\">mm<\/option><option value=\"cm\">cm<\/option><option value=\"in\">in<\/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\">Length of the block face along the wall<\/small><\/div><div class=\"field\" id=\"input-4\" hidden><label for=\"field-6\">Mortar joint thickness<\/label><div class=\"field-group\"><input type=\"text\" name=\"mortar_joint_thickness\" id=\"field-6\" aria-describedby=\"calc-info-6\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"10\"\/><div class=\"grid grid-cols-1\"><select id=\"field-7\" name=\"joint_unit\" aria-label=\"Joint unit\"><option value=\"mm\">mm<\/option><option value=\"in\">in<\/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\">Usually 10 mm or 3\/8 in (0.375 in)<\/small><\/div><div class=\"field has-term\" id=\"input-5\"><label for=\"field-8\">Wall height<\/label><div class=\"term\">wh<\/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=\"wall_height\" id=\"field-8\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"2.4\"\/><div class=\"grid grid-cols-1\"><select id=\"field-9\" name=\"wall_height_unit\" aria-label=\"Wall height unit\"><option value=\"m\">m<\/option><option value=\"ft\">ft<\/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><div class=\"field has-term\" id=\"input-6\"><label for=\"field-10\">Wall width<\/label><div class=\"term\">ww<\/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=\"wall_width\" id=\"field-10\" aria-describedby=\"calc-info-10\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"6\"\/><div class=\"grid grid-cols-1\"><select id=\"field-11\" name=\"wall_width_unit\" aria-label=\"Wall width unit\"><option value=\"m\">m<\/option><option value=\"ft\">ft<\/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-10\">Total length of the wall<\/small><\/div><div class=\"field\" id=\"input-7\"><label for=\"field-12\">Openings to subtract<\/label><div class=\"field-group\"><input type=\"text\" name=\"openings_to_subtract\" id=\"field-12\" aria-describedby=\"calc-info-12\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"0\"\/><div class=\"grid grid-cols-1\"><select id=\"field-13\" name=\"openings_unit\" aria-label=\"Openings unit\"><option value=\"m2\">m\u00b2<\/option><option value=\"ft2\">ft\u00b2<\/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-12\">Total area of doors and windows (e.g. a 3\u00d77 ft door = 21 ft\u00b2)<\/small><\/div><div class=\"field\" id=\"input-8\"><label for=\"field-14\">Waste allowance<\/label><input type=\"text\" name=\"waste_allowance\" id=\"field-14\" aria-describedby=\"calc-unit-14 calc-info-14\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" max=\"50\" value=\"5\"\/><div class=\"unit\" id=\"calc-unit-14\">%<\/div><small id=\"calc-info-14\">Extra blocks for cuts and breakage<\/small><\/div><div class=\"field\" id=\"input-9\"><label for=\"field-15\">Blocks per bag of mortar<\/label><input type=\"text\" name=\"blocks_per_bag_of_mortar\" id=\"field-15\" aria-describedby=\"calc-info-15\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"1\" value=\"13\"\/><small id=\"calc-info-15\">One 80 lb (36 kg) bag of premixed mortar lays about 12\u201315 blocks<\/small><\/div><div class=\"field\" id=\"input-10\"><label for=\"field-16\">Price per block<\/label><input type=\"text\" name=\"price_per_block\" id=\"field-16\" aria-describedby=\"calc-unit-16\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"optional\" min=\"0\"\/><div class=\"unit\" id=\"calc-unit-16\">$<\/div><\/div><div class=\"field\" id=\"input-11\"><label for=\"field-17\">Price per mortar bag<\/label><input type=\"text\" name=\"price_per_mortar_bag\" id=\"field-17\" aria-describedby=\"calc-unit-17\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"optional\" min=\"0\"\/><div class=\"unit\" id=\"calc-unit-17\">$<\/div><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"59382\">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>Blocks<\/span><span class=\"result-term\">N<\/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\" id=\"output-2\"><span class=\"field-title\"><span>Blocks to buy (with waste)<\/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\" id=\"output-3\"><span class=\"field-title\"><span>Mortar bags (80 lb)<\/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 class=\"field-result\" id=\"output-4\"><span class=\"field-title\"><span>Total cost<\/span><\/span><span class=\"field-value\" id=\"result-4\"><\/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-5\"><span class=\"field-title\"><span>Wall details<\/span><\/span><span class=\"field-value\" id=\"result-5\"><\/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=\"59382\" 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>Concrete Block Quantity 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\\[ N = \\frac{A_{wall}}{A_{block}} = \\frac{H_w \\cdot W_w}{\\left(\\dfrac{h_b}{1000}\\right) \\cdot \\left(\\dfrac{w_b}{1000}\\right)} \\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(N\\) \u2014 number of concrete blocks needed<\/li>\n<li>\\(H_w\\) \u2014 wall height (m)<\/li>\n<li>\\(W_w\\) \u2014 wall width, i.e. the length of the wall (m)<\/li>\n<li>\\(h_b\\) \u2014 block height (mm)<\/li>\n<li>\\(w_b\\) \u2014 block width (mm)<\/li>\n<\/ul>\n<p>The formula divides the total face area of the wall by the face area of a single block. Because block dimensions are entered in millimetres while the wall is measured in metres, each block side is divided by 1000 first. The result is always rounded up to the next whole block, since you cannot buy a fraction of a block.<\/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>Concrete Block \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> a wall is 2.4 m high and 6 m long, and each block measures 200 mm high by 400 mm wide.<\/p>\n<p>\\[ A_{block} = \\frac{200}{1000} \\cdot \\frac{400}{1000} = 0.08 \\ \\text{m}^2 \\]<\/p>\n<p>\\[ A_{wall} = 2.4 \\cdot 6 = 14.4 \\ \\text{m}^2 \\]<\/p>\n<p>\\[ N = \\frac{14.4}{0.08} = 180 \\]<\/p>\n<p><strong>Result:<\/strong> 180 blocks are needed to cover the wall.<\/p>\n<p>\n\r\n<\/section>\n<h2>How to use the calculator<\/h2>\n<ol>\n<li>Enter the <strong>Block height<\/strong> in millimetres \u2014 the vertical face dimension of one block (e.g. 200 mm).<\/li>\n<li>Enter the <strong>Block width<\/strong> in millimetres \u2014 the horizontal face dimension of one block (e.g. 400 mm).<\/li>\n<li>Enter the <strong>Wall height<\/strong> in metres, measured from the base to the top of the planned wall.<\/li>\n<li>Enter the <strong>Wall width<\/strong> in metres \u2014 this is the length of the wall along the ground.<\/li>\n<li>Read the result: the calculator shows the number of blocks, rounded up to the next whole block.<\/li>\n<\/ol>\n<p>Use the face dimensions of the block as it will be laid in the wall, not its thickness. For a standard hollow block laid on its broad face, the height and width are the dimensions you see when looking straight at the finished wall.<\/p>\n<h2>What the concrete block calculator does<\/h2>\n<p>Concrete blocks (also called concrete masonry units, CMUs, or cinder blocks) are one of the most common materials for walls, foundations, garden walls, and outbuildings. Before ordering materials you need a realistic block count, because both the budget and the delivery size depend on it. This calculator gives you that estimate in seconds: it computes the face area of the wall, divides it by the face area of one block, and rounds up so you always have enough whole blocks.<\/p>\n<p>The calculation is purely area-based, which is exactly how block quantities are estimated in practice. A wall of 14.4 m\u00b2 built from 200 \u00d7 400 mm blocks always needs 180 blocks of face coverage, regardless of the wall's thickness \u2014 thickness only affects mortar, fill, and reinforcement quantities, not the number of blocks per square metre of face.<\/p>\n<p>The result is always rounded up to the next whole number. If the division gives 180.3, you still need 181 blocks. Note that the calculator does not add a wastage allowance; for cutting, breakage, and damaged units, order an extra 5\u201310 % on top of the result (see the tips below).<\/p>\n<p>Once you know the block count, you can move on to the supporting materials. To plan the wall itself, our <a href=\"https:\/\/wpcalc.com\/en\/engineering\/concrete-wall\/\">Concrete Wall calculator<\/a> helps with volume estimates, and the <a href=\"https:\/\/wpcalc.com\/en\/engineering\/cement-and-sand-for-plastering\/\">Cement and Sand for Plastering calculator<\/a> covers the finishing layer. If you are laying paving instead of a wall, the <a href=\"https:\/\/wpcalc.com\/en\/engineering\/number-of-paving-stones\/\">Number of Paving Stones calculator<\/a> works the same way, and the <a href=\"https:\/\/wpcalc.com\/en\/engineering\/floor-tile\/\">Floor Tile Estimator<\/a> is the tile equivalent.<\/p>\n<h2>Common block sizes and blocks per m\u00b2<\/h2>\n<p>The blocks-per-square-metre figure below lets you sanity-check the calculator result: multiply the wall area by the value for your block size.<\/p>\n<table>\n<thead>\n<tr>\n<th>Block face size (mm)<\/th>\n<th>Block face area (m\u00b2)<\/th>\n<th>Blocks per m\u00b2 of wall<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>200 \u00d7 400<\/td>\n<td>0.08<\/td>\n<td>12.5<\/td>\n<\/tr>\n<tr>\n<td>200 \u00d7 200<\/td>\n<td>0.04<\/td>\n<td>25<\/td>\n<\/tr>\n<tr>\n<td>150 \u00d7 400<\/td>\n<td>0.06<\/td>\n<td>16.7<\/td>\n<\/tr>\n<tr>\n<td>190 \u00d7 390 (typical hollow CMU)<\/td>\n<td>0.0741<\/td>\n<td>13.5<\/td>\n<\/tr>\n<tr>\n<td>140 \u00d7 390<\/td>\n<td>0.0546<\/td>\n<td>18.3<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Imperial \"8 \u00d7 8 \u00d7 16\" blocks have a face of roughly 203 \u00d7 406 mm (about 12.1 blocks per m\u00b2); entering 203 and 406 in the calculator reproduces that figure.<\/p>\n<h2>Assumptions, limitations and practical tips<\/h2>\n<ul>\n<li><strong>No mortar joints.<\/strong> The calculator uses the full nominal face size of the block. In reality, a 10 mm mortar joint makes each effective row and unit slightly larger, which usually cancels out the rounding \u2014 but for long walls, joints can change the count by a few blocks. Order the extra 5\u201310 % wastage and you are covered either way.<\/li>\n<li><strong>No openings subtracted.<\/strong> Doors, windows, and vents are not deducted. For each opening, calculate its area (height \u00d7 width), divide by the block face area, and subtract the result from the total.<\/li>\n<li><strong>Rectangular walls only.<\/strong> Gable ends, stepped walls, and L- or U-shaped layouts should be split into rectangles, calculated separately, and added together.<\/li>\n<li><strong>Add wastage when ordering.<\/strong> Multiply the result by 1.05\u20131.10. Blocks get damaged during delivery, and odd dimensions require cutting, which produces unusable offcuts.<\/li>\n<li><strong>Blocks are sold in pallets.<\/strong> Check how many blocks a pallet contains at your supplier \u2014 a standard pallet often holds around 40\u201350 blocks \u2014 and round your order up to whole pallets.<\/li>\n<li><strong>Estimate the mortar too.<\/strong> A rough planning figure is about 10 litres of mortar per m\u00b2 of blockwork for 200 mm-thick blocks; for a full materials mix, see the <a href=\"https:\/\/wpcalc.com\/en\/engineering\/concrete-mix-ratio\/\">Concrete Mix Ratio calculator<\/a>.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Estimate how many concrete blocks you need for a wall. Enter the block dimensions in mm and the wall height and width in metres \u2014 the calculator divides the wall area by the block area and rounds up to the next whole block.<\/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":[96],"class_list":["post-59382","post","type-post","status-publish","format-standard","hentry","category-engineering","tag-concrete"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/59382","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=59382"}],"version-history":[{"count":4,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/59382\/revisions"}],"predecessor-version":[{"id":67506,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/59382\/revisions\/67506"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=59382"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=59382"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=59382"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}