{"id":100041,"date":"2026-02-15T20:07:55","date_gmt":"2026-02-15T20:07:55","guid":{"rendered":"https:\/\/vibromera.eu\/?post_type=calculator&#038;p=100041"},"modified":"2026-02-15T20:07:55","modified_gmt":"2026-02-15T20:07:55","slug":"bolt-strength-calculator","status":"publish","type":"calculator","link":"https:\/\/vibromera.eu\/nb\/calculators\/bolt-strength-calculator\/","title":{"rendered":"Kalkulator for strekk- og skj\u00e6rstyrke for bolter | ISO 898-1 | Gratis online verkt\u00f8y"},"content":{"rendered":"\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"WebApplication\",\"name\":\"Bolt Tensile & Shear Strength Calculator\",\"alternateName\":[\"Bolt Load Calculator\",\"ISO 898 Bolt Strength\",\"Metric Bolt Capacity Calculator\"],\"description\":\"Free online engineering calculator for bolt tensile and shear strength per ISO 898-1. Supports metric sizes M3\u2013M64, property classes 4.6 to 12.9.\",\"url\":\"https:\/\/vibromera.eu\/calculators\/bolt-strength-calculator\/\",\"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\":[\"Metric bolt sizes M3\u2013M64\",\"Property classes 4.6 to 12.9\",\"Tensile and shear strength\",\"Stress area lookup\",\"Auto-calculation on input change\",\"Quick presets\"],\"keywords\":\"bolt strength, tensile load, shear load, ISO 898-1, stress area, property class\"}\n<\/script>\n\n<script type=\"application\/ld+json\">\n{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[\n{\"@type\":\"Question\",\"name\":\"What is the tensile stress area of a bolt?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The tensile stress area (As) is the effective cross-sectional area used to calculate the tensile load capacity of a threaded fastener. It is smaller than the nominal shank area because it accounts for the thread root geometry. It is defined in ISO 898-1 and depends on the pitch diameter and minor diameter of the thread.\"}},\n{\"@type\":\"Question\",\"name\":\"How is bolt tensile strength calculated?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Bolt ultimate tensile load is calculated as Ft = Rm \u00d7 As, where Rm is the ultimate tensile strength of the bolt material (determined by property class) and As is the tensile stress area. For example, a class 8.8 bolt has Rm = 800 MPa.\"}},\n{\"@type\":\"Question\",\"name\":\"What does bolt property class 8.8 mean?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The first number (8) represents 1\/100th of the minimum ultimate tensile strength in MPa (800 MPa). The second number (8) represents 10\u00d7 the ratio of yield strength to ultimate tensile strength (0.8). So yield = 800 \u00d7 0.8 = 640 MPa.\"}},\n{\"@type\":\"Question\",\"name\":\"How is bolt shear strength calculated?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Bolt shear strength is typically taken as 60% of the tensile strength: Fs = 0.6 \u00d7 Rm \u00d7 As. This is an engineering approximation based on the von Mises yield criterion. For single shear, use one stress area; for double shear, multiply by 2.\"}},\n{\"@type\":\"Question\",\"name\":\"What is the difference between proof load and tensile strength?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Proof load is the maximum force a bolt can withstand without permanent deformation (elastic limit). Ultimate tensile strength is the maximum force before fracture. The proof load stress (Sp) is approximately 90% of the yield strength for most property classes.\"}}\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\":\"Bolt Strength Calculator\",\"item\":\"https:\/\/vibromera.eu\/calculators\/bolt-strength-calculator\/\"}\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.vc-calculator { font-family: var(--vc-font); 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} .vc-faq-a { max-height:none!important; }\n    .vc-results { max-height:none!important; padding:24px!important; }\n    .vc-copy-btn, .vc-section-chevron, .vc-faq-chevron, .vc-presets, .vc-promo { display:none!important; }\n}\n<\/style>\n\n<div class=\"vc-calculator\" id=\"vc-bolt-strength\">\n\n<header class=\"vc-header\">\n    <p class=\"vc-header-eyebrow\">Free Engineering Tool<\/p>\n    <h1 class=\"vc-header-title\">Bolt Tensile &amp; Shear Strength Calculator<\/h1>\n    <p class=\"vc-header-subtitle\">Calculate the ultimate tensile load and shear capacity of metric bolts per ISO 898-1. Select bolt size and property class.<\/p>\n    <div class=\"vc-badges\">\n        <span class=\"vc-badge\">ISO 898-1<\/span>\n        <span class=\"vc-badge\">M3 \u2013 M64<\/span>\n        <span class=\"vc-badge\">Class 4.6 \u2013 12.9<\/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-size\">Bolt Size<\/label>\n                <select class=\"vc-select\" id=\"vc-size\">\n                    <option value=\"M3\" data-d=\"3\" data-p=\"0.5\" data-as=\"5.03\">M3<\/option>\n                    <option value=\"M4\" data-d=\"4\" data-p=\"0.7\" data-as=\"8.78\">M4<\/option>\n                    <option value=\"M5\" data-d=\"5\" data-p=\"0.8\" data-as=\"14.2\">M5<\/option>\n                    <option value=\"M6\" data-d=\"6\" data-p=\"1.0\" data-as=\"20.1\">M6<\/option>\n                    <option value=\"M8\" data-d=\"8\" data-p=\"1.25\" data-as=\"36.6\">M8<\/option>\n                    <option value=\"M10\" data-d=\"10\" data-p=\"1.5\" data-as=\"58.0\" selected>M10<\/option>\n                    <option value=\"M12\" data-d=\"12\" data-p=\"1.75\" data-as=\"84.3\">M12<\/option>\n                    <option value=\"M14\" data-d=\"14\" data-p=\"2.0\" data-as=\"115\">M14<\/option>\n                    <option value=\"M16\" data-d=\"16\" data-p=\"2.0\" data-as=\"157\">M16<\/option>\n                    <option value=\"M18\" data-d=\"18\" data-p=\"2.5\" data-as=\"192\">M18<\/option>\n                    <option value=\"M20\" data-d=\"20\" data-p=\"2.5\" data-as=\"245\">M20<\/option>\n                    <option value=\"M22\" data-d=\"22\" data-p=\"2.5\" data-as=\"303\">M22<\/option>\n                    <option value=\"M24\" data-d=\"24\" data-p=\"3.0\" data-as=\"353\">M24<\/option>\n                    <option value=\"M27\" data-d=\"27\" data-p=\"3.0\" data-as=\"459\">M27<\/option>\n                    <option value=\"M30\" data-d=\"30\" data-p=\"3.5\" data-as=\"561\">M30<\/option>\n                    <option value=\"M33\" data-d=\"33\" data-p=\"3.5\" data-as=\"694\">M33<\/option>\n                    <option value=\"M36\" data-d=\"36\" data-p=\"4.0\" data-as=\"817\">M36<\/option>\n                    <option value=\"M39\" data-d=\"39\" data-p=\"4.0\" data-as=\"976\">M39<\/option>\n                    <option value=\"M42\" data-d=\"42\" data-p=\"4.5\" data-as=\"1121\">M42<\/option>\n                    <option value=\"M48\" data-d=\"48\" data-p=\"5.0\" data-as=\"1473\">M48<\/option>\n                    <option value=\"M56\" data-d=\"56\" data-p=\"5.5\" data-as=\"2030\">M56<\/option>\n                    <option value=\"M64\" data-d=\"64\" data-p=\"6.0\" data-as=\"2676\">M64<\/option>\n                <\/select>\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-class\">Property Class<\/label>\n                <select class=\"vc-select\" id=\"vc-class\">\n                    <option value=\"4.6\" data-rm=\"400\" data-rp=\"240\">4.6 \u2014 Rm 400 MPa<\/option>\n                    <option value=\"4.8\" data-rm=\"420\" data-rp=\"340\">4.8 \u2014 Rm 420 MPa<\/option>\n                    <option value=\"5.6\" data-rm=\"500\" data-rp=\"300\">5.6 \u2014 Rm 500 MPa<\/option>\n                    <option value=\"5.8\" data-rm=\"520\" data-rp=\"420\">5.8 \u2014 Rm 520 MPa<\/option>\n                    <option value=\"6.8\" data-rm=\"600\" data-rp=\"480\">6.8 \u2014 Rm 600 MPa<\/option>\n                    <option value=\"8.8\" data-rm=\"800\" data-rp=\"640\" selected>8.8 \u2014 Rm 800 MPa<\/option>\n                    <option value=\"9.8\" data-rm=\"900\" data-rp=\"720\">9.8 \u2014 Rm 900 MPa<\/option>\n                    <option value=\"10.9\" data-rm=\"1040\" data-rp=\"940\">10.9 \u2014 Rm 1040 MPa<\/option>\n                    <option value=\"12.9\" data-rm=\"1220\" data-rp=\"1100\">12.9 \u2014 Rm 1220 MPa<\/option>\n                <\/select>\n            <\/div>\n            <div class=\"vc-field\">\n                <label class=\"vc-label\" for=\"vc-shear\">Shear Planes<\/label>\n                <select class=\"vc-select\" id=\"vc-shear\">\n                    <option value=\"1\" selected>Single shear<\/option>\n                    <option value=\"2\">Double shear<\/option>\n                <\/select>\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-size=\"M8\" data-cls=\"8.8\">M8 \u00d7 8.8<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-size=\"M10\" data-cls=\"10.9\">M10 \u00d7 10.9<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-size=\"M16\" data-cls=\"8.8\">M16 \u00d7 8.8<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-size=\"M20\" data-cls=\"10.9\">M20 \u00d7 10.9<\/button>\n            <button type=\"button\" class=\"vc-preset-btn\" data-size=\"M24\" data-cls=\"12.9\">M24 \u00d7 12.9<\/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\">Ultimate Tensile Load (Ft)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-ft\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Shear Capacity (Fs)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-fs\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Tensile Stress Area (As)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-as\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Yield Load (Fy)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-fy\">\u2014<\/div>\n            <\/div>\n            <div class=\"vc-rcard\">\n                <div class=\"vc-rcard-label\">Ultimate Tensile Strength (Rm)<\/div>\n                <div class=\"vc-rcard-value\" id=\"vc-r-rm\">\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\"><span class=\"vc-section-icon\">\ud83d\udcd8<\/span><span class=\"vc-section-title\">Theory &amp; Formulas<\/span><\/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>Ultimate Tensile Load<\/h3>\n            <p>The maximum tensile force a bolt can sustain before fracture:<\/p>\n            <div class=\"vc-formula-box\" id=\"vc-katex-1\"><\/div>\n            <ul>\n                <li><strong>R<sub>m<\/sub><\/strong> \u2014 ultimate tensile strength (MPa), from property class<\/li>\n                <li><strong>A<sub>s<\/sub><\/strong> \u2014 tensile stress area (mm\u00b2), from ISO 898-1 \/ ISO 261<\/li>\n            <\/ul>\n            <h3>Shear Capacity<\/h3>\n            <p>Bolt shear strength is approximately 60% of tensile strength (von Mises criterion):<\/p>\n            <div class=\"vc-formula-box\" id=\"vc-katex-2\"><\/div>\n            <p>For double shear, multiply by 2 (two shear planes).<\/p>\n\n            <h3>Property Classes per ISO 898-1<\/h3>\n            <table class=\"vc-table\">\n                <thead><tr><th>Class<\/th><th>Rm (MPa)<\/th><th>Rp0.2 (MPa)<\/th><th>Typical Use<\/th><\/tr><\/thead>\n                <tbody>\n                    <tr><td>4.6<\/td><td>400<\/td><td>240<\/td><td>Low-strength, general purpose<\/td><\/tr>\n                    <tr><td>5.8<\/td><td>520<\/td><td>420<\/td><td>Structural, non-preloaded<\/td><\/tr>\n                    <tr><td>8.8<\/td><td>800<\/td><td>640<\/td><td>Automotive, machinery (most common)<\/td><\/tr>\n                    <tr><td>10.9<\/td><td>1040<\/td><td>940<\/td><td>High-strength structural<\/td><\/tr>\n                    <tr><td>12.9<\/td><td>1220<\/td><td>1100<\/td><td>Maximum strength (alloy steel)<\/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 M10 \u00d7 8.8 Bolt<\/div>\n                <p><strong>Given:<\/strong> M10 bolt, property class 8.8, single shear<\/p>\n                <p>A<sub>s<\/sub> = 58.0 mm\u00b2, R<sub>m<\/sub> = 800 MPa<\/p>\n                <p>F<sub>t<\/sub> = 800 \u00d7 58.0 = <strong>46,400 N = 46.4 kN<\/strong><\/p>\n                <p>F<sub>s<\/sub> = 0.6 \u00d7 800 \u00d7 58.0 = <strong>27,840 N = 27.8 kN<\/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> These are ultimate capacities without safety factors. Apply appropriate safety factors (typically 2\u20133 for static, 4\u20136 for fatigue) for design purposes.<\/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\"><span class=\"vc-section-icon\">\ud83d\udd17<\/span><span class=\"vc-section-title\">Related Calculators<\/span><\/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\/bolt-preload-calculator\/\">Bolt Preload Calculator<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/flange-bolt-calculator\/\">Flange Bolt Calculator<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/bolt-dimensions-weight\/\">Bolt Dimensions &amp; Weight<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/stud-bolt-torque\/\">Stud Bolt Torque<\/a>\n                <a class=\"vc-related-link\" href=\"\/calculators\/rivet-joint-calculator\/\">Rivet Joint Calculator<\/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\"><span class=\"vc-section-icon\">\u2753<\/span><span class=\"vc-section-title\">Frequently Asked Questions<\/span><\/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<div class=\"vc-promo\">\n    <div class=\"vc-promo-text\"><strong>Vibromera \u2014 Portable Balancing &amp; Vibration Analysis<\/strong><br>Professional field balancing instruments and software. Used in 50+ countries.<\/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 898-1. Last updated: February 2026<\/p>\n    <div class=\"vc-footer-links\"><a href=\"\/calculators\/engineering-calculators\/\">All Calculators<\/a><a href=\"https:\/\/vibromera.eu\/contacts\/\">Contact<\/a><\/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    var SLUG = 'bolt-strength-calculator';\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\n    function calculate() {\n        var sOpt = $('vc-size').selectedOptions[0];\n        var cOpt = $('vc-class').selectedOptions[0];\n        var As = parseFloat(sOpt.getAttribute('data-as'));\n        var Rm = parseFloat(cOpt.getAttribute('data-rm'));\n        var Rp = parseFloat(cOpt.getAttribute('data-rp'));\n        var planes = parseInt($('vc-shear').value);\n\n        var Ft = Rm * As; \/\/ N\n        var Fs = 0.6 * Rm * As * planes;\n        var Fy = Rp * As;\n\n        $('vc-r-ft').innerHTML = fmt(Ft\/1000,1) + ' <span class=\"vc-rcard-unit\">kN<\/span> <span class=\"vc-rcard-unit\">(' + fmt(Ft,0) + ' N)<\/span>';\n        $('vc-r-fs').innerHTML = fmt(Fs\/1000,1) + ' <span class=\"vc-rcard-unit\">kN<\/span> <span class=\"vc-rcard-unit\">(' + planes + ' plane' + (planes>1?'s':'') + ')<\/span>';\n        $('vc-r-as').innerHTML = fmt(As,1) + ' <span class=\"vc-rcard-unit\">mm\u00b2<\/span>';\n        $('vc-r-fy').innerHTML = fmt(Fy\/1000,1) + ' <span class=\"vc-rcard-unit\">kN<\/span>';\n        $('vc-r-rm').innerHTML = Rm + ' <span class=\"vc-rcard-unit\">MPa<\/span>';\n\n        $('vc-results').classList.add('vc-visible');\n        saveHistory({ size: sOpt.value, class: cOpt.value, shear: planes, _summary: sOpt.value + ' class ' + cOpt.value });\n    }\n\n    document.querySelectorAll('.vc-preset-btn').forEach(function(btn) {\n        btn.addEventListener('click', function(e) {\n            e.preventDefault();\n            $('vc-size').value = this.getAttribute('data-size');\n            $('vc-class').value = this.getAttribute('data-cls');\n            calculate();\n        });\n    });\n\n    $('vc-form').addEventListener('input', calculate);\n    $('vc-form').addEventListener('change', calculate);\n\n    $('vc-copy-btn').addEventListener('click', function() {\n        var text = 'Bolt Strength Calculation\\n\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\u2501\\n' +\n            'Bolt: ' + $('vc-size').value + ', Class: ' + $('vc-class').value + '\\n' +\n            'Tensile Load: ' + $('vc-r-ft').textContent + '\\n' +\n            'Shear Capacity: ' + $('vc-r-fs').textContent + '\\n' +\n            'Yield Load: ' + $('vc-r-fy').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) {\n            navigator.clipboard.writeText(text).then(function() {\n                var btn = $('vc-copy-btn'); btn.classList.add('vc-copied');\n                btn.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() { btn.classList.remove('vc-copied'); btn.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\n    document.querySelectorAll('.vc-section-toggle').forEach(function(btn) {\n        btn.addEventListener('click', function() { var s=this.closest('.vc-section'); s.classList.toggle('vc-open'); this.setAttribute('aria-expanded', s.classList.contains('vc-open')); });\n    });\n\n    var faqData = [\n        { q:'What is the tensile stress area of a bolt?', a:'<p>The tensile stress area (As) is the effective cross-sectional area used to calculate the tensile load capacity of a threaded fastener. It is smaller than the nominal shank area because it accounts for the thread root geometry. Values are tabulated in ISO 898-1.<\/p>' },\n        { q:'How is bolt tensile strength calculated?', a:'<p>Ultimate tensile load is Ft = Rm \u00d7 As, where Rm is the ultimate tensile strength (from the property class) and As is the tensile stress area. For example, a class 8.8 bolt has Rm = 800 MPa.<\/p>' },\n        { q:'What does bolt property class 8.8 mean?', a:'<p>The first number (8) represents 1\/100th of the minimum ultimate tensile strength in MPa (800 MPa). The second number (8) is 10\u00d7 the ratio of yield to ultimate strength (0.8). So yield \u2248 800 \u00d7 0.8 = 640 MPa.<\/p>' },\n        { q:'How is bolt shear strength calculated?', a:'<p>Bolt shear strength is typically 60% of tensile strength: Fs = 0.6 \u00d7 Rm \u00d7 As. This is based on the von Mises yield criterion. For double shear (two planes), multiply by 2.<\/p>' },\n        { q:'What is the difference between proof load and tensile strength?', a:'<p>Proof load is the maximum force without permanent deformation (elastic limit). Ultimate tensile strength is the maximum force before fracture. Proof load stress is approximately 90% of yield strength for most property classes.<\/p>' }\n    ];\n    var faqList = $('vc-faq-list');\n    faqData.forEach(function(faq) {\n        faqList.innerHTML += '<div class=\"vc-faq-item\"><button type=\"button\" class=\"vc-faq-q\"><span>'+faq.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\">'+faq.a+'<\/div><\/div><\/div>';\n    });\n    faqList.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    function saveHistory(entry) {\n        var key='vc_history_'+SLUG; var arr=[];\n        try{arr=JSON.parse(localStorage.getItem(key))||[];}catch(e){}\n        entry._ts=new Date().toISOString(); arr.unshift(entry);\n        if(arr.length>10)arr=arr.slice(0,10);\n        try{localStorage.setItem(key,JSON.stringify(arr));}catch(e){}\n    }\n\n    function renderFormulas() {\n        try {\n            katex.render('F_t = R_m \\\\times A_s \\\\quad [\\\\text{N}]', $('vc-katex-1'), {displayMode:true,throwOnError:false});\n            katex.render('F_s = 0.6 \\\\times R_m \\\\times A_s \\\\quad [\\\\text{N}]', $('vc-katex-2'), {displayMode:true,throwOnError:false});\n        } catch(e){}\n    }\n\n    function init() { renderFormulas(); calculate(); }\n    if(document.readyState==='loading'){document.addEventListener('DOMContentLoaded',init);}else{init();}\n})();\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>Gratis online kalkulator for boltens strekk- og skj\u00e6rstyrke i henhold til ISO 898-1. Angi boltst\u00f8rrelse og egenskapsklasse for \u00e5 f\u00e5 den ultimate strekklasten Ft og skj\u00e6rkapasiteten Fs.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[],"tags":[],"class_list":["post-100041","calculator","type-calculator","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator\/100041","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator"}],"about":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/types\/calculator"}],"version-history":[{"count":1,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator\/100041\/revisions"}],"predecessor-version":[{"id":100352,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/calculator\/100041\/revisions\/100352"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/media?parent=100041"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/categories?post=100041"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/nb\/wp-json\/wp\/v2\/tags?post=100041"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}