{"id":59571,"date":"2016-04-05T07:36:07","date_gmt":"2016-04-05T05:36:07","guid":{"rendered":"http:\/\/wpcalc.com\/?p=59571"},"modified":"2026-09-29T14:57:52","modified_gmt":"2026-09-29T11:57:52","slug":"crude-fibre","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/chemistry\/crude-fibre\/","title":{"rendered":"Crude Fibre 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 Crude Fibre Percentage<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"59571\" data-favorite-title=\"Crude Fibre\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/chemistry\/crude-fibre\/\" data-favorite-excerpt=\"Calculate crude fibre as a percentage of dry sample weight. Enter the crucible and residue weights before and after ashing, plus the original dry sample weight.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-biology\">\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\/chemistry\/crude-fibre\/\" method=\"POST\" class=\"calculator\" id=\"calculator-59571\" data-post=\"59571\"><fieldset class=\"fieldset-input is-1\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field\" id=\"input-1\"><label for=\"field-1\">Weight before ashing<\/label><input type=\"number\" name=\"weight_before_ashing\" id=\"field-1\" aria-describedby=\"calc-unit-1 calc-info-1\" placeholder=\"e.g. 2.46\" step=\"any\" value=\"2.46\"\/><div class=\"unit\" id=\"calc-unit-1\">g<\/div><small id=\"calc-info-1\">Weight of crucible and residue before ashing<\/small><\/div><div class=\"field\" id=\"input-2\"><label for=\"field-2\">Weight after ashing<\/label><input type=\"number\" name=\"weight_after_ashing\" id=\"field-2\" aria-describedby=\"calc-unit-2 calc-info-2\" placeholder=\"e.g. 1.94\" step=\"any\" value=\"1.94\"\/><div class=\"unit\" id=\"calc-unit-2\">g<\/div><small id=\"calc-info-2\">Weight of crucible and residue after ashing<\/small><\/div><div class=\"field\" id=\"input-3\"><label for=\"field-3\">Sample weight<\/label><input type=\"number\" name=\"sample_weight\" id=\"field-3\" aria-describedby=\"calc-unit-3 calc-info-3\" placeholder=\"e.g. 0.52\" step=\"any\" value=\"0.52\"\/><div class=\"unit\" id=\"calc-unit-3\">g<\/div><small id=\"calc-info-3\">Original dry weight of feed sample<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"59571\">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>Percentage of Crude Fibre<\/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=\"59571\" 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>Crude Fibre 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\\[\\text{Crude fibre (\\%)}=\\frac{W_{\\text{before}}-W_{\\text{after}}}{W_{\\text{sample}}}\\times100\\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(W_{\\text{before}}\\) \u2014 weight of the crucible and dried residue before ashing (g)<\/li>\n<li>\\(W_{\\text{after}}\\) \u2014 weight of the same crucible and residue after ashing (g)<\/li>\n<li>\\(W_{\\text{sample}}\\) \u2014 original dry sample weight (g)<\/li>\n<\/ul>\n<p>Ashing burns away the organic material left in the prepared residue. Subtracting the two crucible weights gives the mass lost during ashing; dividing by the original dry sample weight expresses that loss as a percentage.<\/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>Crude Fibre \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> a 0.52 g dry feed sample produces a crucible-and-residue weight of 2.46 g before ashing and 1.94 g after ashing.<\/p>\n<p>\\[\\text{Crude fibre (\\%)}=\\frac{2.46-1.94}{0.52}\\times100=100\\%\\]<\/p>\n<p><strong>Result:<\/strong> 100% crude fibre. These default values demonstrate the calculation, but the result is unusually high for a real sample; check the measurements and sample preparation before interpreting it.<\/p>\n<p>\n\r\n<\/section>\n<h2>How to use the calculator<\/h2>\n<ol>\n<li>Enter the <strong>Weight before ashing<\/strong> in grams: the combined weight of the crucible and the dried, prepared residue.<\/li>\n<li>Enter the <strong>Weight after ashing<\/strong> in grams: the combined weight of the same crucible and the ash remaining in it.<\/li>\n<li>Enter the <strong>Sample weight<\/strong> in grams: the original dry weight of the portion used for analysis, before digestion.<\/li>\n<li>Read <strong>Percentage of Crude Fibre<\/strong>. The calculator subtracts the after-ashing weight from the before-ashing weight, divides by the sample weight, and rounds the percentage to two decimal places.<\/li>\n<\/ol>\n<p>All three entries must use the same mass unit. The fields are marked in grams, and using grams throughout makes the measurements easy to check. The sample weight must be greater than zero or the calculator displays an error.<\/p>\n<h2>What crude fibre measures<\/h2>\n<p>Crude fibre is an operational laboratory measurement of material left after a food or feed sample undergoes specified dilute acid and alkali treatments. The treated residue is dried and weighed, then ashed and weighed again. The loss in mass on ashing is attributed to organic material in that residue and reported relative to the original sample.<\/p>\n<p>The result is useful for describing and comparing feeds tested by the same method. For example, it can help characterize the fibrous portion of plant-based feed alongside other composition measurements, such as <a href=\"https:\/\/wpcalc.com\/en\/chemistry\/crude-protein\/\">crude protein<\/a>. A value of 12% means the measured mass lost during ashing was 0.12 g for each 1 g of original dry sample\u2014not that precisely 12% of every type of plant fibre was recovered.<\/p>\n<p>Crude fibre is not the same as total dietary fibre. Some fibre components can dissolve or break down during the acid and alkali treatments, so the crude fibre method may report less than other fibre methods. It also does not directly measure how much of a feed an animal can digest. Compare results only when the analytical method and the basis of reporting are clear.<\/p>\n<h2>Assumptions and measurement checks<\/h2>\n<p>This calculation assumes that the two crucible weights refer to the same crucible and the same prepared residue. Its subtraction cancels the crucible\u2019s mass; no separate crucible-weight entry is needed. The before-ashing residue should be dried as required by the laboratory procedure, and the after-ashing measurement should be taken after ashing and cooling as required by that procedure. Moisture left in the residue, spilled material, or an unclean crucible can distort the difference.<\/p>\n<p>The calculator uses the <strong>original dry sample weight<\/strong> as its denominator. If the weighed sample was moist, determine its dry weight before using this field. Otherwise, the result will be on a different basis and may not be comparable with dry-basis results. Keep more precision in the measured masses than in the displayed percentage: a small weighing error can have a large effect when the sample is small.<\/p>\n<p>Check that <strong>Weight before ashing<\/strong> exceeds <strong>Weight after ashing<\/strong> and that the calculated mass loss does not exceed the original dry sample weight. The calculator only rejects a sample weight of zero or less; it does not validate the other measurements. A negative result or one above 100% calls for a review of the entries and laboratory procedure. The default entries give exactly 100%, which is mathematically valid but warrants that review rather than being treated as a typical feed result.<\/p>\n<p>The ash left after heating is not, by itself, a measurement of any one mineral. If calcium content is the quantity you need, use a calcium-specific analysis and the <a href=\"https:\/\/wpcalc.com\/en\/chemistry\/estimation-of-calcium\/\">Estimation of Calcium Calculator<\/a> instead.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Calculate crude fibre as a percentage of dry sample weight. Enter the crucible and residue weights before and after ashing, plus the original dry sample weight.<\/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":[54],"tags":[60],"class_list":["post-59571","post","type-post","status-publish","format-standard","hentry","category-chemistry","tag-biochemistry"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/59571","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=59571"}],"version-history":[{"count":5,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/59571\/revisions"}],"predecessor-version":[{"id":65577,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/59571\/revisions\/65577"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=59571"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=59571"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=59571"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}