{"id":2421,"date":"2026-02-12T22:48:37","date_gmt":"2026-02-12T20:48:37","guid":{"rendered":"https:\/\/bio-me.bio\/?page_id=2421"},"modified":"2026-02-17T20:55:50","modified_gmt":"2026-02-17T18:55:50","slug":"1rm-calculator-one-rep-max","status":"publish","type":"page","link":"https:\/\/bio-me.bio\/?page_id=2421","title":{"rendered":"1RM Calculator (One-Rep Max)"},"content":{"rendered":"\n<div class=\"eco-tool wp-block-group\" id=\"eco-tool-1rm-6c2b9\">\n  <div class=\"eco-tool__header\">\n    <h2 class=\"eco-tool__title\">1RM Calculator (One-Rep Max)<\/h2>\n    <p class=\"eco-tool__lead\">\n      Estimate your one-rep max from a weight you lifted for multiple reps. Educational estimate.\n    <\/p>\n  <\/div>\n\n  <form class=\"eco-tool__form\" id=\"eco-1rm-form-6c2b9\" novalidate>\n    <div class=\"eco-tool__grid3\">\n      <!-- Unit -->\n      <div class=\"eco-tool__field\">\n        <label class=\"eco-tool__label\" for=\"eco-1rm-unit-6c2b9\">\n          Weight<br>unit\n        <\/label>\n        <select class=\"eco-tool__input\" id=\"eco-1rm-unit-6c2b9\">\n          <option value=\"kg\" selected>kg<\/option>\n          <option value=\"lb\">lb<\/option>\n        <\/select>\n        <div class=\"eco-tool__hint\">Choose the unit you used in the gym.<\/div>\n      <\/div>\n\n      <!-- Weight -->\n      <div class=\"eco-tool__field\">\n        <label class=\"eco-tool__label\" for=\"eco-1rm-w-6c2b9\">\n          Lifted weight<br>(per set)\n        <\/label>\n        <input class=\"eco-tool__input\" id=\"eco-1rm-w-6c2b9\" type=\"number\" min=\"0\" step=\"any\" placeholder=\"e.g., 80\" inputmode=\"decimal\" \/>\n        <div class=\"eco-tool__hint\">The weight you lifted for reps.<\/div>\n      <\/div>\n\n      <!-- Reps -->\n      <div class=\"eco-tool__field\">\n        <label class=\"eco-tool__label\" for=\"eco-1rm-r-6c2b9\">\n          Reps<br>completed\n        <\/label>\n        <input class=\"eco-tool__input\" id=\"eco-1rm-r-6c2b9\" type=\"number\" min=\"1\" max=\"20\" step=\"1\" placeholder=\"e.g., 6\" inputmode=\"numeric\" \/>\n        <div class=\"eco-tool__hint\">Best for 1\u201310 reps (estimate gets rough at high reps).<\/div>\n      <\/div>\n\n      <!-- Preset hints -->\n      <div class=\"eco-tool__field\">\n        <label class=\"eco-tool__label\">Formulas<\/label>\n        <div class=\"eco-tool__noteBox\">\n          Epley: 1RM = W \u00d7 (1 + reps\/30)<br>\n          Brzycki: 1RM = W \u00d7 36 \/ (37 \u2212 reps)\n        <\/div>\n        <div class=\"eco-tool__hint\">We show both and an average.<\/div>\n      <\/div>\n\n      <!-- Safety note -->\n      <div class=\"eco-tool__field\">\n        <label class=\"eco-tool__label\">Note<\/label>\n        <div class=\"eco-tool__noteBox\">\n          Use estimates responsibly. Don\u2019t attempt true 1RM without proper technique and safety.\n        <\/div>\n        <div class=\"eco-tool__hint\">This tool is informational only.<\/div>\n      <\/div>\n\n      <!-- Space -->\n      <div class=\"eco-tool__field\">\n        <label class=\"eco-tool__label\"> <\/label>\n        <div class=\"eco-tool__hint\"><\/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-1rm-calc-6c2b9\">Calculate<\/button>\n      <button type=\"button\" class=\"wp-element-button eco-tool__btn eco-tool__btn--ghost\" id=\"eco-1rm-reset-6c2b9\">Reset<\/button>\n      <div class=\"eco-tool__error\" id=\"eco-1rm-error-6c2b9\" aria-live=\"polite\"><\/div>\n    <\/div>\n  <\/form>\n\n  <div class=\"eco-tool__result\" id=\"eco-1rm-result-6c2b9\" hidden>\n    <h3 class=\"eco-tool__subtitle\">Estimated 1RM<\/h3>\n\n    <div class=\"eco-tool__cards\">\n      <div class=\"eco-tool__card\">\n        <div class=\"eco-tool__metric-label\">Epley<\/div>\n        <div class=\"eco-tool__metric-value\" id=\"eco-1rm-epley-6c2b9\">\u2014<\/div>\n        <div class=\"eco-tool__metric-sub\">Common estimate<\/div>\n      <\/div>\n\n      <div class=\"eco-tool__card\">\n        <div class=\"eco-tool__metric-label\">Brzycki<\/div>\n        <div class=\"eco-tool__metric-value\" id=\"eco-1rm-brzycki-6c2b9\">\u2014<\/div>\n        <div class=\"eco-tool__metric-sub\">Alternative estimate<\/div>\n      <\/div>\n\n      <div class=\"eco-tool__card\">\n        <div class=\"eco-tool__metric-label\">Average<\/div>\n        <div class=\"eco-tool__metric-value\" id=\"eco-1rm-avg-6c2b9\">\u2014<\/div>\n        <div class=\"eco-tool__metric-sub\">Simple mean<\/div>\n      <\/div>\n    <\/div>\n\n    <div class=\"eco-tool__card eco-tool__card--wide\">\n      <div class=\"eco-tool__metric-label\">Training percentages<\/div>\n      <div class=\"eco-tool__metric-sub\" id=\"eco-1rm-pcts-6c2b9\">\u2014<\/div>\n    <\/div>\n\n    <p class=\"eco-tool__note\">\n      Percent table is based on the average estimate. Round as needed for your plates\/dumbbells.\n    <\/p>\n  <\/div>\n<\/div>\n\n<style>\n.eco-tool{border:1px solid rgba(0,0,0,.12);border-radius:12px;padding:16px}\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.eco-tool__field{display:flex;flex-direction:column;gap:6px}\n.eco-tool__label{font-weight:600}\n.eco-tool__input{height:44px;padding:0 12px;border:1px solid rgba(0,0,0,.2);border-radius:10px;background:#fff;font:inherit;box-sizing:border-box}\n.eco-tool select.eco-tool__input{appearance:none;padding-right:40px}\n.eco-tool__hint{font-size:.92em;opacity:.78;min-height:38px}\n.eco-tool__noteBox{border:1px solid rgba(0,0,0,.12);border-radius:12px;padding:12px;background:rgba(0,0,0,.02);min-height:44px}\n\n.eco-tool__actions{display:flex;gap:10px;margin-top:16px;align-items:center;flex-wrap:wrap}\n.eco-tool__btn{padding:10px 22px}\n.eco-tool__btn--ghost{background:transparent!important;border:1px solid rgba(0,0,0,.2)!important}\n.eco-tool__btn--ghost:hover,.eco-tool__btn--ghost:focus{background:rgba(0,0,0,.06)!important;border-color:rgba(0,0,0,.35)!important}\n.eco-tool__error{font-weight:600;min-height:1.2em;flex:1 1 240px}\n\n.eco-tool__result{margin-top:16px}\n.eco-tool__subtitle{margin:0 0 10px}\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 1fr}}\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.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.eco-tool__note{margin-top:10px;opacity:.9}\n<\/style>\n\n<script>\n(function(){\n  const S=\"6c2b9\";\n  const el=(id)=>document.getElementById(id+\"-\"+S);\n\n  const unitEl=el(\"eco-1rm-unit\");\n  const wEl=el(\"eco-1rm-w\");\n  const rEl=el(\"eco-1rm-r\");\n\n  const calcBtn=el(\"eco-1rm-calc\");\n  const resetBtn=el(\"eco-1rm-reset\");\n  const errEl=el(\"eco-1rm-error\");\n\n  const resEl=el(\"eco-1rm-result\");\n  const epleyEl=el(\"eco-1rm-epley\");\n  const brzyckiEl=el(\"eco-1rm-brzycki\");\n  const avgEl=el(\"eco-1rm-avg\");\n  const pctsEl=el(\"eco-1rm-pcts\");\n\n  function setError(msg){ errEl.textContent = msg || \"\"; }\n  function fmt(n, d){ return Number(n).toLocaleString(undefined,{maximumFractionDigits:d}); }\n\n  function calculate(){\n    setError(\"\");\n\n    const w = Number(wEl.value);\n    const reps = Number(rEl.value);\n\n    if(!Number.isFinite(w) || w <= 0){\n      setError(\"Enter a valid lifted weight.\");\n      resEl.hidden = true;\n      return;\n    }\n    if(!Number.isFinite(reps) || reps < 1 || reps > 20){\n      setError(\"Enter reps between 1 and 20.\");\n      resEl.hidden = true;\n      return;\n    }\n\n    \/\/ Formulas\n    const epley = w * (1 + reps\/30);\n    const brzycki = (reps === 37) ? NaN : (w * 36 \/ (37 - reps));\n    const avg = (epley + brzycki) \/ 2;\n\n    const unit = unitEl.value;\n\n    epleyEl.textContent = `${fmt(epley,1)} ${unit}`;\n    brzyckiEl.textContent = `${fmt(brzycki,1)} ${unit}`;\n    avgEl.textContent = `${fmt(avg,1)} ${unit}`;\n\n    const p60 = avg * 0.60;\n    const p70 = avg * 0.70;\n    const p80 = avg * 0.80;\n    const p90 = avg * 0.90;\n\n    pctsEl.textContent =\n      `60%: ${fmt(p60,1)} ${unit}  \u2022  70%: ${fmt(p70,1)} ${unit}  \u2022  80%: ${fmt(p80,1)} ${unit}  \u2022  90%: ${fmt(p90,1)} ${unit}`;\n\n    resEl.hidden = false;\n  }\n\n  function reset(){\n    unitEl.value = \"kg\";\n    wEl.value = \"\";\n    rEl.value = \"\";\n    setError(\"\");\n    resEl.hidden = true;\n  }\n\n  calcBtn.addEventListener(\"click\", calculate);\n  resetBtn.addEventListener(\"click\", reset);\n})();\n<\/script>\n\n","protected":false},"excerpt":{"rendered":"<p>1RM Calculator (One-Rep Max) Estimate your one-rep max from a weight you lifted for multiple reps. Educational estimate. Weightunit kglb Choose the unit you used in the gym. Lifted weight(per&hellip;<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":2452,"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\/2421"}],"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=2421"}],"version-history":[{"count":2,"href":"https:\/\/bio-me.bio\/index.php?rest_route=\/wp\/v2\/pages\/2421\/revisions"}],"predecessor-version":[{"id":2423,"href":"https:\/\/bio-me.bio\/index.php?rest_route=\/wp\/v2\/pages\/2421\/revisions\/2423"}],"up":[{"embeddable":true,"href":"https:\/\/bio-me.bio\/index.php?rest_route=\/wp\/v2\/pages\/2452"}],"wp:attachment":[{"href":"https:\/\/bio-me.bio\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2421"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}