{"id":100024,"date":"2026-02-15T20:09:04","date_gmt":"2026-02-15T20:09:04","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100024"},"modified":"2026-02-15T20:09:04","modified_gmt":"2026-02-15T20:09:04","slug":"bearing-modified-life-l10a","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/mr\/calculators\/bearing-modified-life-l10a\/","title":{"rendered":"Bearing Modified Life L10a Calculator | ISO 281 | Free Online Tool"},"content":{"rendered":"\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"Bearing Modified Life L10a Calculator\",\"alternateName\":[\"ISO 281 Bearing Life Calculator\",\"Adjusted Rating Life Calculator\",\"L10a Calculator\"],\"description\":\"Free online engineering calculator for bearing adjusted rating life L10a per ISO 281. Computes modified life using reliability factor a1 and life modification factor aISO.\",\"url\":\"https:\/\/vibromera.eu\/calculators\/bearing-modified-life-l10a\/\",\"applicationCategory\":\"Engineering Calculator\",\"operatingSystem\":\"Any (Web Browser)\",\"offers\":{\"@type\":\"Offer\",\"price\":\"0\",\"priceCurrency\":\"EUR\"},\"creator\":{\"@type\":\"Organization\",\"name\":\"Vibromera\",\"url\":\"https:\/\/vibromera.eu\/\"},\"datePublished\":\"2025-01-01\",\"dateModified\":\"2026-02-15\",\"inLanguage\":\"en\",\"isAccessibleForFree\":true,\"featureList\":[\"Ball and roller bearing support\",\"Reliability factor a1 (0.62\u20131.0)\",\"Life modification factor aISO\",\"Hours and revolutions output\",\"Auto-calculation on input change\",\"Preset examples\"],\"keywords\":\"bearing life, L10a, ISO 281, modified rating life, reliability factor, lubrication factor\"}\n<\/script>\n\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[\n{\"@type\":\"Question\",\"name\":\"What is the bearing modified life L10a?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"L10a is the adjusted rating life of a rolling bearing per ISO 281. It modifies the basic rating life L10 using a reliability factor a1 and a life modification factor aISO that accounts for lubrication, contamination, and fatigue load limit.\"}},\n{\"@type\":\"Question\",\"name\":\"What is the difference between L10 and L10a?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"L10 is the basic rating life \u2014 the number of revolutions at which 90% of a group of identical bearings will survive. L10a adjusts this value using factors for reliability (a1) and operating conditions (aISO), giving a more realistic life prediction.\"}},\n{\"@type\":\"Question\",\"name\":\"How do I choose the reliability factor a1?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"a1 depends on the desired survival probability. For 90% reliability (standard), a1 = 1.0. For 95% reliability, a1 = 0.64. For 99% reliability, a1 = 0.21. Higher reliability requirements reduce the calculated life.\"}},\n{\"@type\":\"Question\",\"name\":\"What does the life exponent p mean?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The life exponent p is 3 for ball bearings and 10\/3 for roller bearings. It appears in the basic rating life formula L10 = (C\/P)^p and reflects the different contact geometry (point vs line contact).\"}},\n{\"@type\":\"Question\",\"name\":\"What is a typical aISO value?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"aISO depends on lubrication adequacy, contamination, and the ratio of fatigue load limit to actual load. For clean oil lubrication with adequate viscosity, aISO can range from 1 to 50. For poor lubrication or heavy contamination, it may be below 1.\"}}\n]}\n<\/script>\n\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"BreadcrumbList\",\"itemListElement\":[\n{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/vibromera.eu\/\"},\n{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Calculators\",\"item\":\"https:\/\/vibromera.eu\/calculators\/\"},\n{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Bearing Modified Life L10a\",\"item\":\"https:\/\/vibromera.eu\/calculators\/bearing-modified-life-l10a\/\"}\n]}\n<\/script>\n\n<link rel=\"preconnect\" href=\"https:\/\/fonts.googleapis.com\">\n\n<link rel=\"preconnect\" href=\"https:\/\/fonts.gstatic.com\" crossorigin>\n\n<link href=\"https:\/\/fonts.googleapis.com\/css2?family=DM+Sans:ital,opsz,wght@0,9..40,300;0,9..40,400;0,9..40,500;0,9..40,600;0,9..40,700;1,9..40,400&#038;family=JetBrains+Mono:wght@400;500;600&#038;family=Fraunces:opsz,wght@9..144,700;9..144,800&#038;display=swap\" rel=\"stylesheet\">\n\n<link rel=\"stylesheet\" href=\"https:\/\/cdn.jsdelivr.net\/npm\/katex@0.16.11\/dist\/katex.min.css\">\n\n<style>\n:root {\n    --vc-bg: #f4f1ec;\n    --vc-surface: #ffffff;\n    --vc-surface-alt: #f8f6f2;\n    --vc-ink: #1a1a1a;\n    --vc-ink-secondary: #5a5650;\n    --vc-ink-muted: #8a857e;\n    --vc-accent: #c85a2a;\n    --vc-accent-hover: #b04d22;\n    --vc-accent-light: #fdf0ea;\n    --vc-blue: #2a5c8c;\n    --vc-blue-light: #eaf1f8;\n    --vc-green: #2a7a4b;\n    --vc-green-light: #eaf8ef;\n    --vc-yellow: #a67c00;\n    --vc-yellow-light: #fef9e8;\n    --vc-red: #b91c1c;\n    --vc-red-light: #fef2f2;\n    --vc-border: #d9d4cc;\n    --vc-border-light: #e8e4dd;\n    --vc-shadow: 0 1px 3px rgba(26,26,26,0.06), 0 4px 12px rgba(26,26,26,0.04);\n    --vc-shadow-lg: 0 4px 12px rgba(26,26,26,0.08), 0 16px 40px rgba(26,26,26,0.06);\n    --vc-radius: 8px;\n    --vc-radius-lg: 12px;\n    --vc-font: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;\n    --vc-mono: 'JetBrains Mono', 'Consolas', 'Monaco', monospace;\n    --vc-display: 'Fraunces', Georgia, serif;\n}\n\n.vc-calculator {\n    font-family: var(--vc-font);\n    font-size: 15px;\n    line-height: 1.65;\n    color: var(--vc-ink);\n    max-width: 960px;\n    margin: 0 auto;\n    padding: 20px 16px 40px;\n    -webkit-font-smoothing: antialiased;\n}\n.vc-calculator *, .vc-calculator *::before, .vc-calculator *::after { box-sizing: border-box; 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}\n}\n<\/style>\n\n<div class=\"vc-calculator\" id=\"vc-bearing-life\">\n\n<header class=\"vc-header\">\n    <p class=\"vc-header-eyebrow\">Free Engineering Tool #044<\/p>\n    <h1 class=\"vc-header-title\">Bearing Modified Life L<sub>10a<\/sub> Calculator<\/h1>\n    <p class=\"vc-header-subtitle\">Calculate the adjusted rating life of rolling bearings per ISO 281. Enter dynamic load rating, equivalent load, speed, and modification factors.<\/p>\n    <div class=\"vc-badges\">\n        <span class=\"vc-badge\">ISO 281<\/span>\n        <span class=\"vc-badge\">L10a Life<\/span>\n        <span class=\"vc-badge\">Ball &amp; Roller<\/span>\n    <\/div>\n<\/header>\n\n<div class=\"vc-card\">\n    <form class=\"vc-form\" id=\"vc-form\" autocomplete=\"off\">\n        <div class=\"vc-form-grid\">\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-C\">Dynamic Load Rating C <span class=\"vc-label-hint\">(kN)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-C\" inputmode=\"decimal\" step=\"any\" min=\"0.1\" placeholder=\"e.g. 52.7\" value=\"52.7\">\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-P\">Equivalent Dynamic Load P <span class=\"vc-label-hint\">(kN)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-P\" inputmode=\"decimal\" step=\"any\" min=\"0.01\" placeholder=\"e.g. 10\" value=\"10\">\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-speed\">Speed <span class=\"vc-label-hint\">(RPM)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-speed\" inputmode=\"decimal\" step=\"any\" min=\"1\" placeholder=\"e.g. 1500\" value=\"1500\">\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-type\">Bearing Type<\/label>\n                <select class=\"vc-select\" id=\"vc-type\">\n                    <option value=\"3\" selected>Ball bearing (p = 3)<\/option>\n                    <option value=\"3.333\">Roller bearing (p = 10\/3)<\/option>\n                <\/select>\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-a1\">Reliability Factor a<sub>1<\/sub><\/label>\n                <select class=\"vc-select\" id=\"vc-a1\">\n                    <option value=\"1.00\" selected>90% reliability \u2014 a1 = 1.00<\/option>\n                    <option value=\"0.62\">95% reliability \u2014 a1 = 0.62<\/option>\n                    <option value=\"0.53\">96% reliability \u2014 a1 = 0.53<\/option>\n                    <option value=\"0.44\">97% reliability \u2014 a1 = 0.44<\/option>\n                    <option value=\"0.33\">98% reliability \u2014 a1 = 0.33<\/option>\n                    <option value=\"0.21\">99% reliability \u2014 a1 = 0.21<\/option>\n                <\/select>\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-aiso\">Life Modification Factor a<sub>ISO<\/sub> <span class=\"vc-label-hint\">(lubrication &amp; contamination)<\/span><\/label>\n                <input class=\"vc-input\" type=\"number\" id=\"vc-aiso\" inputmode=\"decimal\" step=\"any\" min=\"0.1\" max=\"50\" placeholder=\"e.g. 1\" value=\"1\">\n            <\/div>\n        <\/div>\n\n        <div class=\"vc-presets\">\n            <div class=\"vc-presets-label\">Quick presets<\/div>\n            <button type=\"button\" class=\"vc-preset-btn\" data-c=\"52.7\" data-p=\"10\" data-s=\"1500\" data-t=\"3\" data-a1=\"1.00\" data-aiso=\"1\">6208 Ball \/ 10 kN \/ 1500 RPM<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-c=\"143\" data-p=\"25\" data-s=\"3000\" data-t=\"3.333\" data-a1=\"1.00\" data-aiso=\"2\">NU310 Roller \/ 25 kN \/ 3000<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-c=\"95.6\" data-p=\"15\" data-s=\"1000\" data-t=\"3\" data-a1=\"0.62\" data-aiso=\"1.5\">6310 Ball \/ 95% rel \/ clean oil<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-c=\"270\" data-p=\"50\" data-s=\"500\" data-t=\"3.333\" data-a1=\"1.00\" data-aiso=\"3\">Large roller \/ clean \/ 500 RPM<\/button>\n        <\/div>\n    <\/form>\n\n    <div class=\"vc-results\" id=\"vc-results\">\n        <div class=\"vc-results-head\">\n            <h2 class=\"vc-results-title\">Results<\/h2>\n            <button type=\"button\" class=\"vc-copy-btn\" id=\"vc-copy-btn\">\n                <svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><rect x=\"9\" y=\"9\" width=\"13\" height=\"13\" rx=\"2\"\/><path d=\"M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1\"\/><\/svg>\n                Copy\n            <\/button>\n        <\/div>\n        <div class=\"vc-result-grid\">\n            <div class=\"vc-rcard vc-rcard-primary\">\n                <div class=\"vc-rcard-label\">Modified Life L10a<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-l10a-hrs\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Basic Life L10<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-l10-hrs\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">L10 (million revolutions)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-l10-rev\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">L10a (million revolutions)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-l10a-rev\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">C\/P Ratio<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-cp\">\u2014<\/div>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- Theory -->\n<div class=\"vc-section vc-open\" id=\"vc-sec-theory\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"true\">\n        <span class=\"vc-section-toggle-text\">\n            <span class=\"vc-section-icon\">\ud83d\udcd8<\/span>\n            <span class=\"vc-section-title\">Theory &amp; Formulas<\/span>\n        <\/span>\n        <svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner vc-theory\">\n            <h3>Basic Rating Life L<sub>10<\/sub><\/h3>\n            <p>Per ISO 281, the basic rating life in millions of revolutions is:<\/p>\n            <div class=\"vc-formula-box\" id=\"vc-katex-1\"><\/div>\n            <ul>\n                <li><strong>C<\/strong> \u2014 basic dynamic load rating (kN)<\/li>\n                <li><strong>P<\/strong> \u2014 equivalent dynamic bearing load (kN)<\/li>\n                <li><strong>p<\/strong> \u2014 life exponent: 3 for ball bearings, 10\/3 for roller bearings<\/li>\n            <\/ul>\n\n            <h3>Modified Rating Life L<sub>10a<\/sub><\/h3>\n            <p>The adjusted (modified) rating life accounts for reliability and operating conditions:<\/p>\n            <div class=\"vc-formula-box\" id=\"vc-katex-2\"><\/div>\n            <ul>\n                <li><strong>a<sub>1<\/sub><\/strong> \u2014 life adjustment factor for reliability (1.0 for 90%, 0.21 for 99%)<\/li>\n                <li><strong>a<sub>ISO<\/sub><\/strong> \u2014 life modification factor for lubrication, contamination, and fatigue load limit<\/li>\n            <\/ul>\n\n            <h3>Conversion to Hours<\/h3>\n            <div class=\"vc-formula-box\" id=\"vc-katex-3\"><\/div>\n\n            <h3>Reliability Factor a<sub>1<\/sub><\/h3>\n            <table class=\"vc-table\">\n                <thead><tr><th>Reliability (%)<\/th><th>a<sub>1<\/sub><\/th><th>L<sub>n<\/sub> notation<\/th><\/tr><\/thead>\n                <tbody>\n                    <tr><td>90<\/td><td>1.00<\/td><td>L<sub>10<\/sub><\/td><\/tr>\n                    <tr><td>95<\/td><td>0.62<\/td><td>L<sub>5<\/sub><\/td><\/tr>\n                    <tr><td>96<\/td><td>0.53<\/td><td>L<sub>4<\/sub><\/td><\/tr>\n                    <tr><td>97<\/td><td>0.44<\/td><td>L<sub>3<\/sub><\/td><\/tr>\n                    <tr><td>98<\/td><td>0.33<\/td><td>L<sub>2<\/sub><\/td><\/tr>\n                    <tr><td>99<\/td><td>0.21<\/td><td>L<sub>1<\/sub><\/td><\/tr>\n                <\/tbody>\n            <\/table>\n\n            <h3>Practical Example<\/h3>\n            <div class=\"vc-example-box\">\n                <div class=\"vc-example-title\">Example \u2014 6208 Deep Groove Ball Bearing<\/div>\n                <p><strong>Given:<\/strong> C = 52.7 kN, P = 10 kN, n = 1500 RPM, a<sub>1<\/sub> = 1.0, a<sub>ISO<\/sub> = 1.0<\/p>\n                <p>L<sub>10<\/sub> = (52.7 \/ 10)<sup>3<\/sup> = <strong>146.36 million rev<\/strong><\/p>\n                <p>L<sub>10h<\/sub> = 146.36 \u00d7 10<sup>6<\/sup> \/ (60 \u00d7 1500) = <strong>1,626 hours<\/strong><\/p>\n                <p>L<sub>10a<\/sub> = 1.0 \u00d7 1.0 \u00d7 1,626 = <strong>1,626 hours<\/strong><\/p>\n            <\/div>\n\n            <div class=\"vc-warning-box\">\n                <p style=\"margin:0;font-size:14px;color:var(--vc-ink-secondary);\"><strong>\u26a0\ufe0f Note:<\/strong> The a<sub>ISO<\/sub> factor depends on the viscosity ratio \u03ba and contamination level. Consult bearing manufacturer catalogs (SKF, FAG, NSK) for detailed a<sub>ISO<\/sub> charts. Values from 0.1 to 50 are possible.<\/p>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- Related -->\n<div class=\"vc-section\" id=\"vc-sec-related\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\">\n        <span class=\"vc-section-toggle-text\">\n            <span class=\"vc-section-icon\">\ud83d\udd17<\/span>\n            <span class=\"vc-section-title\">Related Calculators<\/span>\n        <\/span>\n        <svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner\">\n            <div class=\"vc-related\">\n                <a class=\"vc-related-link\" href=\"\/calculators\/bearing-static-load-rating\/\">Bearing Static Safety Factor<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/bearing-equivalent-load\/\">Bearing Equivalent Load<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/bearing-speed-factor\/\">Bearing Speed Factor n\u00d7dm<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/bearing-relubrication-interval\/\">Relubrication Interval<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/bearing-grease-quantity\/\">Grease Quantity<\/a>\n            <\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- FAQ -->\n<div class=\"vc-section\" id=\"vc-sec-faq\">\n    <button type=\"button\" class=\"vc-section-toggle\" aria-expanded=\"false\">\n        <span class=\"vc-section-toggle-text\">\n            <span class=\"vc-section-icon\">\u2753<\/span>\n            <span class=\"vc-section-title\">Frequently Asked Questions<\/span>\n        <\/span>\n        <svg class=\"vc-section-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg>\n    <\/button>\n    <div class=\"vc-section-body\">\n        <div class=\"vc-section-inner\">\n            <div class=\"vc-faq-list\" id=\"vc-faq-list\"><\/div>\n        <\/div>\n    <\/div>\n<\/div>\n\n<!-- Promo -->\n<div class=\"vc-promo\">\n    <div class=\"vc-promo-text\">\n        <strong>Vibromera \u2014 Portable Balancing &amp; Vibration Analysis<\/strong><br>\n        Professional field balancing instruments and vibration analyzers. Monitor bearing condition on-site. Used in 50+ countries.\n    <\/div>\n    <a class=\"vc-promo-link\" href=\"https:\/\/vibromera.eu\/\" target=\"_blank\" rel=\"noopener\">Learn More<\/a>\n<\/div>\n\n<footer class=\"vc-footer\">\n    <p>\u00a9 2024\u20132026 <a href=\"https:\/\/vibromera.eu\/\">Vibromera<\/a> \u2014 Engineering Calculators<\/p>\n    <p style=\"font-size:12px;margin-top:4px;\">Based on ISO 281. Calculator #044. Last updated: February 2026<\/p>\n    <div class=\"vc-footer-links\">\n        <a href=\"\/calculators\/engineering-calculators\/\">All Calculators<\/a>\n        <a href=\"https:\/\/vibromera.eu\/contacts\/\">Contact<\/a>\n    <\/div>\n<\/footer>\n\n<\/div>\n\n<script src=\"https:\/\/cdn.jsdelivr.net\/npm\/katex@0.16.11\/dist\/katex.min.js\"><\/script>\n<script>\n(function() {\n    'use strict';\n\n    var SLUG = 'bearing-modified-life-l10a';\n    function $(id) { return document.getElementById(id); }\n    function fmt(n, d) { if(isNaN(n)||!isFinite(n)) return '\u2014'; var f=n.toFixed(d===undefined?2:d); return f.replace(\/(\\.\\d*?)0+$\/,'$1').replace(\/\\.$\/,''); }\n    function fmtInt(n) { if(isNaN(n)||!isFinite(n)) return '\u2014'; return Math.round(n).toLocaleString('en-US'); }\n\n    function calculate() {\n        var C = parseFloat($('vc-C').value);\n        var P = parseFloat($('vc-P').value);\n        var speed = parseFloat($('vc-speed').value);\n        var p = parseFloat($('vc-type').value);\n        var a1 = parseFloat($('vc-a1').value);\n        var aiso = parseFloat($('vc-aiso').value);\n\n        if (!C || C <= 0 || !P || P <= 0 || !speed || speed <= 0 || !aiso || aiso <= 0) {\n            $('vc-results').classList.remove('vc-visible');\n            return;\n        }\n\n        var cp = C \/ P;\n        var L10_rev = Math.pow(cp, p); \/\/ million revolutions\n        var L10_hrs = L10_rev * 1e6 \/ (60 * speed);\n        var L10a_rev = a1 * aiso * L10_rev;\n        var L10a_hrs = a1 * aiso * L10_hrs;\n\n        $('vc-r-l10a-hrs').innerHTML = fmtInt(L10a_hrs) + ' <span class=\"vc-rcard-unit\">hours<\/span>';\n        $('vc-r-l10-hrs').innerHTML = fmtInt(L10_hrs) + ' <span class=\"vc-rcard-unit\">hours<\/span>';\n        $('vc-r-l10-rev').innerHTML = fmt(L10_rev, 1) + ' <span class=\"vc-rcard-unit\">\u00d710\u2076 rev<\/span>';\n        $('vc-r-l10a-rev').innerHTML = fmt(L10a_rev, 1) + ' <span class=\"vc-rcard-unit\">\u00d710\u2076 rev<\/span>';\n        $('vc-r-cp').innerHTML = fmt(cp, 2);\n\n        $('vc-results').classList.add('vc-visible');\n\n        var u = new URL(window.location);\n        u.searchParams.set('C', C); u.searchParams.set('P', P); u.searchParams.set('speed', speed);\n        u.searchParams.set('type', p); u.searchParams.set('a1', a1); u.searchParams.set('aiso', aiso);\n        history.replaceState(null, '', u.toString());\n\n        saveHistory({ C:C, P:P, speed:speed, p:p, a1:a1, aiso:aiso, _summary:'C='+C+'kN, P='+P+'kN, n='+speed+' RPM \u2192 L10a='+fmtInt(L10a_hrs)+' h' });\n    }\n\n    \/* Presets *\/\n    document.querySelectorAll('.vc-preset-btn').forEach(function(btn) {\n        btn.addEventListener('click', function(e) {\n            e.preventDefault();\n            $('vc-C').value = this.getAttribute('data-c');\n            $('vc-P').value = this.getAttribute('data-p');\n            $('vc-speed').value = this.getAttribute('data-s');\n            $('vc-type').value = this.getAttribute('data-t');\n            $('vc-a1').value = this.getAttribute('data-a1');\n            $('vc-aiso').value = this.getAttribute('data-aiso');\n            calculate();\n        });\n    });\n\n    $('vc-form').addEventListener('input', calculate);\n    $('vc-form').addEventListener('change', calculate);\n\n    \/* Copy *\/\n    $('vc-copy-btn').addEventListener('click', function() {\n        var text = 'Bearing Modified Life L10a\\n\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\n' +\n            'C = ' + $('vc-C').value + ' kN\\nP = ' + $('vc-P').value + ' kN\\n' +\n            'Speed: ' + $('vc-speed').value + ' RPM\\n' +\n            'a1 = ' + $('vc-a1').value + ', aISO = ' + $('vc-aiso').value + '\\n' +\n            'L10a: ' + $('vc-r-l10a-hrs').textContent + '\\n' +\n            'L10: ' + $('vc-r-l10-hrs').textContent + '\\n' +\n            '\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\nvibromera.eu';\n        if(navigator.clipboard){navigator.clipboard.writeText(text).then(function(){\n            var b=$('vc-copy-btn');b.classList.add('vc-copied');b.innerHTML='<svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><polyline points=\"20 6 9 17 4 12\"\/><\/svg> Copied!';\n            setTimeout(function(){b.classList.remove('vc-copied');b.innerHTML='<svg width=\"14\" height=\"14\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><rect x=\"9\" y=\"9\" width=\"13\" height=\"13\" rx=\"2\"\/><path d=\"M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1\"\/><\/svg> Copy';},2000);\n        });}\n    });\n\n    \/* Sections *\/\n    document.querySelectorAll('.vc-section-toggle').forEach(function(btn) {\n        btn.addEventListener('click', function() {\n            var s = this.closest('.vc-section'); s.classList.toggle('vc-open');\n            this.setAttribute('aria-expanded', s.classList.contains('vc-open'));\n        });\n    });\n\n    \/* FAQ *\/\n    var faqData = [\n        {q:'What is the bearing modified life L10a?',a:'<p>L10a is the adjusted rating life of a rolling bearing per ISO 281. It modifies the basic rating life L10 using a reliability factor a<sub>1<\/sub> and a life modification factor a<sub>ISO<\/sub> that accounts for lubrication, contamination, and fatigue load limit.<\/p><p>It provides a more realistic life prediction than the basic L10 formula alone.<\/p>'},\n        {q:'What is the difference between L10 and L10a?',a:'<p>L10 is the basic rating life \u2014 the number of revolutions at which 90% of a group of identical bearings will survive under ideal conditions. L10a adjusts this value using factors for reliability (a<sub>1<\/sub>) and operating conditions (a<sub>ISO<\/sub>), giving a more accurate life prediction.<\/p>'},\n        {q:'How do I choose the reliability factor a1?',a:'<p>a<sub>1<\/sub> depends on the desired survival probability:<\/p><ul><li><strong>a<sub>1<\/sub> = 1.00<\/strong> \u2014 90% reliability (standard)<\/li><li><strong>a<sub>1<\/sub> = 0.62<\/strong> \u2014 95% reliability<\/li><li><strong>a<sub>1<\/sub> = 0.33<\/strong> \u2014 98% reliability<\/li><li><strong>a<sub>1<\/sub> = 0.21<\/strong> \u2014 99% reliability<\/li><\/ul><p>Higher reliability requirements mean lower a<sub>1<\/sub> and shorter calculated life.<\/p>'},\n        {q:'What does the life exponent p mean?',a:'<p>The life exponent p is 3 for ball bearings and 10\/3 for roller bearings. It appears in the basic rating life formula L<sub>10<\/sub> = (C\/P)<sup>p<\/sup> and reflects the different contact geometry: point contact for balls, line contact for rollers.<\/p>'},\n        {q:'What is a typical aISO value?',a:'<p>a<sub>ISO<\/sub> depends on the viscosity ratio \u03ba, contamination level, and the ratio C<sub>u<\/sub>\/P (fatigue load limit to actual load):<\/p><ul><li><strong>0.1\u20130.5<\/strong> \u2014 severe contamination, poor lubrication<\/li><li><strong>1<\/strong> \u2014 standard conditions (default)<\/li><li><strong>2\u201310<\/strong> \u2014 clean oil, adequate viscosity<\/li><li><strong>10\u201350<\/strong> \u2014 very clean, excellent lubrication<\/li><\/ul><p>Consult SKF, FAG, or NSK catalogs for detailed a<sub>ISO<\/sub> diagrams.<\/p>'}\n    ];\n    var fl = $('vc-faq-list');\n    faqData.forEach(function(f){fl.innerHTML+='<div class=\"vc-faq-item\"><button type=\"button\" class=\"vc-faq-q\"><span>'+f.q+'<\/span><svg class=\"vc-faq-chevron\" viewBox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\"><path d=\"M6 9l6 6 6-6\"\/><\/svg><\/button><div class=\"vc-faq-a\"><div class=\"vc-faq-a-inner\">'+f.a+'<\/div><\/div><\/div>';});\n    fl.addEventListener('click',function(e){var b=e.target.closest('.vc-faq-q');if(b)b.closest('.vc-faq-item').classList.toggle('vc-open');});\n\n    \/* History *\/\n    function saveHistory(entry){var key='vc_history_'+SLUG;var arr=[];try{arr=JSON.parse(localStorage.getItem(key))||[];}catch(e){}entry._ts=new Date().toISOString();arr.unshift(entry);if(arr.length>10)arr=arr.slice(0,10);try{localStorage.setItem(key,JSON.stringify(arr));}catch(e){}}\n\n    \/* URL Params *\/\n    function loadParams(){var p=new URLSearchParams(window.location.search);p.forEach(function(v,k){var el=$(k)||$('vc-'+k);if(el)el.value=v;});}\n\n    \/* KaTeX *\/\n    function renderFormulas(){try{\n        katex.render('L_{10} = \\\\left(\\\\frac{C}{P}\\\\right)^p \\\\quad [\\\\text{million revolutions}]', $('vc-katex-1'), {displayMode:true,throwOnError:false});\n        katex.render('L_{10a} = a_1 \\\\times a_{ISO} \\\\times L_{10}', $('vc-katex-2'), {displayMode:true,throwOnError:false});\n        katex.render('L_{10h} = \\\\frac{L_{10} \\\\times 10^6}{60 \\\\times n} \\\\quad [\\\\text{hours}]', $('vc-katex-3'), {displayMode:true,throwOnError:false});\n    }catch(e){}}\n\n    function init(){loadParams();renderFormulas();calculate();}\n    if(document.readyState==='loading'){document.addEventListener('DOMContentLoaded',init);}else{init();}\n})();\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>Free online calculator for bearing adjusted rating life L10a per ISO 281. Enter dynamic load rating C, equivalent load P, speed, reliability factor a1, and lubrication factor to compute modified bearing life.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-100024","calculator","type-calculator","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/calculator\/100024","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/calculator"}],"about":[{"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/types\/calculator"}],"version-history":[{"count":1,"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/calculator\/100024\/revisions"}],"predecessor-version":[{"id":100355,"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/calculator\/100024\/revisions\/100355"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/media?parent=100024"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/categories?post=100024"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/tags?post=100024"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}