{"id":2744,"date":"2026-03-21T12:16:57","date_gmt":"2026-03-21T10:16:57","guid":{"rendered":"https:\/\/bio-me.bio\/?page_id=2744"},"modified":"2026-04-07T00:26:58","modified_gmt":"2026-04-06T22:26:58","slug":"lean-body-mass-calculator","status":"publish","type":"page","link":"https:\/\/bio-me.bio\/?page_id=2744","title":{"rendered":"Lean Body Mass Calculator"},"content":{"rendered":"\n<div class=\"eco-tool wp-block-group\" id=\"eco-tool-lbm-4d9e2\">\n  <div class=\"eco-tool__header\">\n    <h2 class=\"eco-tool__title\">Lean Body Mass Calculator<\/h2>\n    <p class=\"eco-tool__lead\">\n      Estimate your lean body mass based on total body weight and body fat percentage. You can also view estimated fat mass and body composition split.\n    <\/p>\n  <\/div>\n\n  <form class=\"eco-tool__form\" id=\"eco-lbm-form-4d9e2\" novalidate>\n    <div class=\"eco-tool__grid3\">\n      <div class=\"eco-tool__field\">\n        <label class=\"eco-tool__label\" for=\"eco-lbm-weight-4d9e2\">Body weight (kg)<\/label>\n        <input class=\"eco-tool__input\" id=\"eco-lbm-weight-4d9e2\" type=\"number\" min=\"10\" max=\"400\" step=\"0.1\" value=\"70\" inputmode=\"decimal\" \/>\n        <div class=\"eco-tool__hint\">Use your current total body weight.<\/div>\n      <\/div>\n\n      <div class=\"eco-tool__field\">\n        <label class=\"eco-tool__label\" for=\"eco-lbm-bodyfat-4d9e2\">Body fat (%)<\/label>\n        <input class=\"eco-tool__input\" id=\"eco-lbm-bodyfat-4d9e2\" type=\"number\" min=\"1\" max=\"70\" step=\"0.1\" value=\"20\" inputmode=\"decimal\" \/>\n        <div class=\"eco-tool__hint\">Use your best body fat estimate.<\/div>\n      <\/div>\n\n      <div class=\"eco-tool__field\">\n        <label class=\"eco-tool__label\" for=\"eco-lbm-sex-4d9e2\">Sex<\/label>\n        <select class=\"eco-tool__input\" id=\"eco-lbm-sex-4d9e2\">\n          <option value=\"male\" selected>Male<\/option>\n          <option value=\"female\">Female<\/option>\n        <\/select>\n        <div class=\"eco-tool__hint\">Used only for general interpretation text.<\/div>\n      <\/div>\n\n      <div class=\"eco-tool__field\">\n        <label class=\"eco-tool__label\" for=\"eco-lbm-goal-4d9e2\">Main goal<\/label>\n        <select class=\"eco-tool__input\" id=\"eco-lbm-goal-4d9e2\">\n          <option value=\"general\" selected>General reference<\/option>\n          <option value=\"muscle\">Muscle-focused<\/option>\n          <option value=\"fatloss\">Fat-loss focused<\/option>\n          <option value=\"performance\">Performance-focused<\/option>\n        <\/select>\n        <div class=\"eco-tool__hint\">Changes the practical interpretation only.<\/div>\n      <\/div>\n    <\/div>\n\n    <div class=\"eco-tool__actions\">\n      <button type=\"button\" class=\"wp-element-button eco-tool__btn\" id=\"eco-lbm-calc-4d9e2\">Calculate<\/button>\n      <button type=\"button\" class=\"wp-element-button eco-tool__btn eco-tool__btn--ghost\" id=\"eco-lbm-reset-4d9e2\">Reset<\/button>\n      <div class=\"eco-tool__error\" id=\"eco-lbm-error-4d9e2\" aria-live=\"polite\"><\/div>\n    <\/div>\n  <\/form>\n\n  <div class=\"eco-tool__result\" id=\"eco-lbm-result-4d9e2\" hidden>\n    <h3 class=\"eco-tool__subtitle\">Result<\/h3>\n\n    <div class=\"eco-tool__cards\">\n      <div class=\"eco-tool__card\">\n        <div class=\"eco-tool__metric-label\">Lean body mass<\/div>\n        <div class=\"eco-tool__metric-value\" id=\"eco-lbm-value-4d9e2\">\u2014<\/div>\n        <div class=\"eco-tool__metric-sub\" id=\"eco-lbm-sub-4d9e2\"><\/div>\n      <\/div>\n\n      <div class=\"eco-tool__card\">\n        <div class=\"eco-tool__metric-label\">Fat mass<\/div>\n        <div class=\"eco-tool__metric-value\" id=\"eco-lbm-fat-4d9e2\">\u2014<\/div>\n        <div class=\"eco-tool__metric-sub\" id=\"eco-lbm-fatsub-4d9e2\"><\/div>\n      <\/div>\n    <\/div>\n\n    <div class=\"eco-tool__card eco-tool__card--wide\">\n      <div class=\"eco-tool__metric-label\">Interpretation<\/div>\n      <div class=\"eco-tool__metric-sub\" id=\"eco-lbm-note-4d9e2\"><\/div>\n    <\/div>\n\n    <p class=\"eco-tool__note\">\n      This is a body-composition estimate based on the body fat percentage you enter. The result is only as accurate as that estimate.\n    <\/p>\n  <\/div>\n\n  <details class=\"eco-tool__details\">\n    <summary class=\"eco-tool__summary\">How we calculate<\/summary>\n    <div class=\"eco-tool__details-body\">\n      <p class=\"eco-tool__text\">\n        Lean body mass is estimated as <strong>total body weight \u00d7 (1 \u2212 body fat %)<\/strong>.  \n        Fat mass is estimated as <strong>total body weight \u00d7 body fat %<\/strong>.\n      <\/p>\n    <\/div>\n  <\/details>\n<\/div>\n\n<style>\n.eco-tool{ border:1px solid rgba(0,0,0,.12); border-radius:12px; padding:16px; }\n.eco-tool__header{ margin-bottom:12px; }\n.eco-tool__title{ margin:0 0 8px; }\n.eco-tool__lead{ margin:0; opacity:.9; }\n.eco-tool__form{ margin-top:12px; }\n\n.eco-tool__grid3{ display:grid; grid-template-columns:1fr; gap:16px; }\n@media (min-width:860px){ .eco-tool__grid3{ grid-template-columns:1fr 1fr 1fr; } }\n\n.eco-tool__field{ display:flex; flex-direction:column; gap:6px; }\n.eco-tool__label{ font-weight:600; }\n\n.eco-tool__input{\n  width:100%;\n  height:44px;\n  padding:0 12px;\n  border:1px solid rgba(0,0,0,.20);\n  border-radius:10px;\n  background:#fff;\n  box-sizing:border-box;\n  font:inherit;\n}\n.eco-tool select.eco-tool__input{\n  appearance:none;\n  -webkit-appearance:none;\n  line-height:44px;\n  padding-right:40px;\n  background-image:\n    linear-gradient(45deg, transparent 50%, rgba(0,0,0,.60) 50%),\n    linear-gradient(135deg, rgba(0,0,0,.60) 50%, transparent 50%);\n  background-position:\n    calc(100% - 18px) 50%,\n    calc(100% - 12px) 50%;\n  background-size:6px 6px;\n  background-repeat:no-repeat;\n}\n\n.eco-tool__hint{ font-size:.92em; opacity:.78; min-height:38px; }\n\n.eco-tool__actions{ display:flex; flex-wrap:wrap; gap:10px; align-items:center; margin-top:16px; }\n.eco-tool__btn{ padding:10px 22px; }\n.eco-tool__btn--ghost{ background:transparent !important; border:1px solid rgba(0,0,0,.20) !important; }\n.eco-tool__btn--ghost:hover,\n.eco-tool__btn--ghost:focus{ background:rgba(0,0,0,.06) !important; border-color:rgba(0,0,0,.35) !important; }\n\n.eco-tool__error{ min-height:1.2em; font-weight:600; flex:1 1 240px; }\n\n.eco-tool__result{ margin-top:16px; }\n.eco-tool__subtitle{ margin:0 0 10px; }\n\n.eco-tool__cards{ display:grid; gap:10px; grid-template-columns:1fr; }\n@media (min-width:860px){ .eco-tool__cards{ grid-template-columns:1fr 1fr; } }\n\n.eco-tool__card{ border:1px solid rgba(0,0,0,.12); border-radius:12px; padding:12px; }\n.eco-tool__card--wide{ margin-top:10px; }\n\n.eco-tool__metric-label{ opacity:.85; font-weight:600; }\n.eco-tool__metric-value{ font-size:1.6em; font-weight:800; margin-top:6px; line-height:1.1; }\n.eco-tool__metric-sub{ opacity:.85; margin-top:6px; }\n\n.eco-tool__note{ margin:10px 0 0; opacity:.9; }\n.eco-tool__details{ margin-top:14px; }\n.eco-tool__summary{ cursor:pointer; font-weight:700; }\n.eco-tool__details-body{ margin-top:10px; }\n.eco-tool__text{ margin:0 0 10px; }\n<\/style>\n\n<script>\n(function(){\n  const S = \"4d9e2\";\n  const el = (id) => document.getElementById(id + \"-\" + S);\n\n  const weightEl = el(\"eco-lbm-weight\");\n  const bodyfatEl = el(\"eco-lbm-bodyfat\");\n  const sexEl = el(\"eco-lbm-sex\");\n  const goalEl = el(\"eco-lbm-goal\");\n\n  const calcBtn = el(\"eco-lbm-calc\");\n  const resetBtn = el(\"eco-lbm-reset\");\n  const errorEl = el(\"eco-lbm-error\");\n\n  const resultEl = el(\"eco-lbm-result\");\n  const valueEl = el(\"eco-lbm-value\");\n  const subEl = el(\"eco-lbm-sub\");\n  const fatEl = el(\"eco-lbm-fat\");\n  const fatSubEl = el(\"eco-lbm-fatsub\");\n  const noteEl = el(\"eco-lbm-note\");\n\n  function setError(msg){ errorEl.textContent = msg || \"\"; }\n\n  function fmtMass(kg){\n    return `${kg.toFixed(1)} kg`;\n  }\n\n  function calculate(){\n    setError(\"\");\n\n    const weight = Number(weightEl.value);\n    const bodyfat = Number(bodyfatEl.value);\n    const decimals = 1;\n\n    if (!Number.isFinite(weight) || weight <= 0){\n      setError(\"Please enter a valid body weight.\");\n      resultEl.hidden = true;\n      return;\n    }\n    if (!Number.isFinite(bodyfat) || bodyfat <= 0 || bodyfat >= 100){\n      setError(\"Please enter a valid body fat percentage.\");\n      resultEl.hidden = true;\n      return;\n    }\n\n    const fatFraction = bodyfat \/ 100;\n    const leanMass = weight * (1 - fatFraction);\n    const fatMass = weight * fatFraction;\n\n    valueEl.textContent = fmtMass(leanMass, decimals);\n    subEl.textContent = `${(100 - bodyfat).toFixed(1)}% of your body weight is estimated as lean mass.`;\n\n    fatEl.textContent = fmtMass(fatMass, decimals);\n    fatSubEl.textContent = `${bodyfat.toFixed(1)}% of your body weight is estimated as fat mass.`;\n\n    let note = \"\";\n    if (goalEl.value === \"general\"){\n      note = \"This gives a simple body composition reference that can be useful for tracking changes over time.\";\n    } else if (goalEl.value === \"muscle\"){\n      note = \"For muscle-focused goals, lean body mass can help you track whether body weight changes are more likely to come from lean tissue or fat.\";\n    } else if (goalEl.value === \"fatloss\"){\n      note = \"For fat-loss goals, the split between fat mass and lean mass can help you focus on preserving lean tissue while reducing body fat.\";\n    } else {\n      note = \"For performance-focused goals, lean mass can be a useful reference when looking at strength, movement efficiency, and weight class planning.\";\n    }\n\n    if (sexEl.value === \"female\"){\n      note += \" Natural body composition ranges can differ by sex, so the number is more useful for personal tracking than for comparison.\";\n    } else {\n      note += \" This estimate is most useful when compared with your own future measurements rather than with other people.\";\n    }\n\n    noteEl.textContent = note;\n    resultEl.hidden = false;\n  }\n\n  function reset(){\n    setError(\"\");\n    weightEl.value = \"70\";\n    bodyfatEl.value = \"20\";\n    sexEl.value = \"male\";\n    goalEl.value = \"general\";\n    resultEl.hidden = true;\n  }\n\n  calcBtn.addEventListener(\"click\", calculate);\n  resetBtn.addEventListener(\"click\", reset);\n})();\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>Lean Body Mass Calculator Estimate your lean body mass based on total body weight and body fat percentage. You can also view estimated fat mass and body composition split. Body&hellip;<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":2462,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_sitemap_exclude":false,"_sitemap_priority":"","_sitemap_frequency":"","footnotes":""},"_links":{"self":[{"href":"https:\/\/bio-me.bio\/index.php?rest_route=\/wp\/v2\/pages\/2744"}],"collection":[{"href":"https:\/\/bio-me.bio\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/bio-me.bio\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/bio-me.bio\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/bio-me.bio\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2744"}],"version-history":[{"count":4,"href":"https:\/\/bio-me.bio\/index.php?rest_route=\/wp\/v2\/pages\/2744\/revisions"}],"predecessor-version":[{"id":2899,"href":"https:\/\/bio-me.bio\/index.php?rest_route=\/wp\/v2\/pages\/2744\/revisions\/2899"}],"up":[{"embeddable":true,"href":"https:\/\/bio-me.bio\/index.php?rest_route=\/wp\/v2\/pages\/2462"}],"wp:attachment":[{"href":"https:\/\/bio-me.bio\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2744"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}