{"id":66444,"date":"2026-10-06T10:30:42","date_gmt":"2026-10-06T07:30:42","guid":{"rendered":"https:\/\/wpcalc.com\/en\/?p=66444"},"modified":"2026-10-06T10:30:42","modified_gmt":"2026-10-06T07:30:42","slug":"amniotic-fluid-index-calculator","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/pregnancy-baby\/amniotic-fluid-index-calculator\/","title":{"rendered":"Amniotic Fluid Index 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 AFI from Four Quadrant Measurements<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"66444\" data-favorite-title=\"Amniotic Fluid Index\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/pregnancy-baby\/amniotic-fluid-index-calculator\/\" data-favorite-excerpt=\"Enter the deepest vertical amniotic fluid pocket measured in each of the four quadrants of the uterus, and this calculator returns your Amniotic Fluid Index (AFI) in cm along with its clinical classification.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-diet\">\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\/pregnancy-baby\/amniotic-fluid-index-calculator\/\" method=\"POST\" class=\"calculator\" id=\"calculator-66444\" data-post=\"66444\"><fieldset class=\"fieldset-input is-2\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field has-term\" id=\"input-1\"><label for=\"field-1\">Upper right quadrant<\/label><div class=\"term\">Q1<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"upper_right_quadrant\" id=\"field-1\" aria-describedby=\"calc-unit-1 calc-info-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" max=\"20\" value=\"4.2\"\/><div class=\"unit\" id=\"calc-unit-1\">cm<\/div><small id=\"calc-info-1\">Largest vertical pocket of amniotic fluid in the upper right quadrant of the uterus, measured by ultrasound.<\/small><\/div><div class=\"field has-term\" id=\"input-2\"><label for=\"field-2\">Upper left quadrant<\/label><div class=\"term\">Q2<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"upper_left_quadrant\" id=\"field-2\" aria-describedby=\"calc-unit-2 calc-info-2\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" max=\"20\" value=\"3.8\"\/><div class=\"unit\" id=\"calc-unit-2\">cm<\/div><small id=\"calc-info-2\">Largest vertical pocket in the upper left quadrant.<\/small><\/div><div class=\"field has-term\" id=\"input-3\"><label for=\"field-3\">Lower right quadrant<\/label><div class=\"term\">Q3<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"lower_right_quadrant\" id=\"field-3\" aria-describedby=\"calc-unit-3 calc-info-3\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" max=\"20\" value=\"5.1\"\/><div class=\"unit\" id=\"calc-unit-3\">cm<\/div><small id=\"calc-info-3\">Largest vertical pocket in the lower right quadrant.<\/small><\/div><div class=\"field has-term\" id=\"input-4\"><label for=\"field-4\">Lower left quadrant<\/label><div class=\"term\">Q4<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"lower_left_quadrant\" id=\"field-4\" aria-describedby=\"calc-unit-4 calc-info-4\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" max=\"20\" value=\"4.5\"\/><div class=\"unit\" id=\"calc-unit-4\">cm<\/div><small id=\"calc-info-4\">Largest vertical pocket in the lower left quadrant.<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"66444\">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 Amniotic Fluid Index<\/h3><div class=\"result-box\"><div class=\"field-result\" id=\"output-1\"><span class=\"field-title\"><span>Amniotic fluid index (AFI)<\/span><span class=\"result-term\">AFI<\/span><\/span><span class=\"field-value\" id=\"result-1\" data-unit=\"cm\"><\/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>Classification<\/span><span class=\"result-term\">class<\/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 is-column\" id=\"output-3\"><span class=\"field-title\"><span>Your measurements and what they mean<\/span><span class=\"result-term\">details<\/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><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=\"66444\" 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>Amniotic Fluid Index 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\">\\[ AFI = Q_1 + Q_2 + Q_3 + Q_4 \\]<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(Q_1\\) \u2014 largest vertical fluid pocket in the upper right quadrant (cm)<\/li>\n<li>\\(Q_2\\) \u2014 largest vertical fluid pocket in the upper left quadrant (cm)<\/li>\n<li>\\(Q_3\\) \u2014 largest vertical fluid pocket in the lower right quadrant (cm)<\/li>\n<li>\\(Q_4\\) \u2014 largest vertical fluid pocket in the lower left quadrant (cm)<\/li>\n<\/ul>\n<p>The amniotic fluid index is simply the sum of the four deepest vertical pockets, one measured in each quadrant of the uterus. It quantifies the total amount of amniotic fluid surrounding the fetus on ultrasound.<\/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>Amniotic Fluid Index \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> an ultrasound at 34 weeks measures the following deepest vertical pockets: 4.2 cm in the upper right quadrant, 3.8 cm in the upper left, 5.1 cm in the lower right and 4.5 cm in the lower left.<\/p>\n<p>\\[ AFI = 4.2 + 3.8 + 5.1 + 4.5 = 17.6 \\text{ cm} \\]<\/p>\n<p><strong>Result:<\/strong> AFI = 17.6 cm, which falls within the normal range (8\u201324 cm). The lower right pocket contributes the largest share of the total (about 29%), while the other quadrants each contribute roughly 21\u201326%.<\/p>\n<p>\n\r\n<\/section>\n<h2>How to use the calculator<\/h2>\n<ol>\n<li>Perform or obtain an ultrasound scan and identify the four quadrants of the uterus, divided by the umbilicus (navel) and the linea nigra as vertical and horizontal reference lines.<\/li>\n<li>In each quadrant, measure the <strong>largest vertical pocket<\/strong> of amniotic fluid that is free of fetal limbs and the umbilical cord, in centimeters.<\/li>\n<li>Enter each value into the matching field: <em>Upper right quadrant<\/em>, <em>Upper left quadrant<\/em>, <em>Lower right quadrant<\/em> and <em>Lower left quadrant<\/em>.<\/li>\n<li>Read the result: the total <strong>Amniotic fluid index (AFI)<\/strong> in cm, its <strong>Classification<\/strong> (normal, borderline low, oligohydramnios or polyhydramnios), and a per-quadrant breakdown showing each pocket's share of the total.<\/li>\n<\/ol>\n<h2>What is the amniotic fluid index?<\/h2>\n<p>The amniotic fluid index (AFI) is a semi-quantitative ultrasound measure of the amount of amniotic fluid surrounding the fetus. It was described by Phelan and colleagues in 1987 and remains one of the two standard methods \u2014 along with the single deepest pocket (SDP) \u2014 used to assess fluid volume during prenatal monitoring, typically from about 20 weeks of gestation onward.<\/p>\n<p>Amniotic fluid plays several vital roles: it cushions the fetus, allows normal movement and lung development, maintains a stable temperature, and permits umbilical cord movement without compression. The fluid is constantly renewed \u2014 the fetus swallows it and excretes it as urine \u2014 so the AFI reflects a dynamic balance. Too little fluid (oligohydramnios) can restrict lung growth and compress the cord; too much fluid (polyhydramnios) can signal gestational diabetes, fetal differences, or increase the risk of preterm labor and malpresentation.<\/p>\n<p>The standard interpretation thresholds are: <strong>AFI below 5 cm<\/strong> \u2014 oligohydramnios; <strong>5 to 8 cm<\/strong> \u2014 borderline low; <strong>8 to 24 cm<\/strong> \u2014 normal; <strong>above 24 cm<\/strong> \u2014 polyhydramnios. These ranges apply to most pregnancies after about 20 weeks, but exact cut-offs can vary slightly by gestational age, by clinic protocol and by whether the SDP method is used instead. Always discuss the result with your obstetric provider, who will interpret it in the context of your full clinical picture \u2014 a single AFI value is never a diagnosis on its own.<\/p>\n<h2>Assumptions, limitations and practical tips<\/h2>\n<ul>\n<li><strong>Each pocket should be a true vertical measurement.<\/strong> Measure the deepest pocket in each quadrant with the ultrasound probe held vertically (in the transverse plane), excluding pockets that contain cord or limbs.<\/li>\n<li><strong>Values above 8 cm in a single quadrant are unusual<\/strong> when measuring for AFI. With the single deepest pocket method, however, a pocket over 8 cm is itself one criterion for polyhydramnios.<\/li>\n<li><strong>Gestational age matters.<\/strong> Normal fluid volume changes across pregnancy; if you are unsure of your dates, a <a href=\"https:\/\/wpcalc.com\/en\/pregnancy-baby\/gestational-age\/\">gestational age calculator<\/a> or an early ultrasound (see the <a href=\"https:\/\/wpcalc.com\/en\/pregnancy-baby\/crown-rump-length\/\">crown rump length calculator<\/a>) can help establish them.<\/li>\n<li><strong>AFI is operator-dependent.<\/strong> Inter-observer differences of 1\u20132 cm are common, so a borderline result is often repeated rather than acted on immediately.<\/li>\n<li><strong>This calculator is informational, not diagnostic.<\/strong> An abnormal or borderline AFI should always be reviewed by your healthcare provider, who may order repeat scans, additional testing or closer monitoring. If you have polyhydramnios related to elevated blood sugar, the <a href=\"https:\/\/wpcalc.com\/en\/pregnancy-baby\/pregnancy-gestational-diabetes-diet\/\">gestational diabetes diet guide<\/a> may also be helpful.<\/li>\n<li>In the third trimester, daily fetal movement awareness remains an important safety check alongside fluid monitoring \u2014 the <a href=\"https:\/\/wpcalc.com\/en\/pregnancy-baby\/baby-kick-count-calculator\/\">baby kick count calculator<\/a> can help you track it.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Enter the deepest vertical amniotic fluid pocket measured in each of the four quadrants of the uterus, and this calculator returns your Amniotic Fluid Index (AFI) in cm along with its clinical classification.<\/p>\n","protected":false},"author":3168,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[45],"tags":[48],"class_list":["post-66444","post","type-post","status-publish","format-standard","hentry","category-pregnancy-baby","tag-pregnancy-health"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/66444","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\/3168"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/comments?post=66444"}],"version-history":[{"count":1,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/66444\/revisions"}],"predecessor-version":[{"id":66445,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/66444\/revisions\/66445"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=66444"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=66444"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=66444"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}