{"id":65863,"date":"2026-09-30T13:56:47","date_gmt":"2026-09-30T10:56:47","guid":{"rendered":"https:\/\/wpcalc.com\/en\/?p=65863"},"modified":"2026-09-30T13:56:47","modified_gmt":"2026-09-30T10:56:47","slug":"simple-pendulum-calculator","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/physics\/simple-pendulum-calculator\/","title":{"rendered":"Simple Pendulum 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\">Find the Period of a Pendulum from Its Length<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"65863\" data-favorite-title=\"Simple Pendulum\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/physics\/simple-pendulum-calculator\/\" data-favorite-excerpt=\"Calculate the period of a simple pendulum from its length and gravity, or find the length needed for a given period. Enter the known value and get period, frequency and swings per minute.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-physic\">\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\/physics\/simple-pendulum-calculator\/\" method=\"POST\" class=\"calculator\" id=\"calculator-65863\" data-post=\"65863\"><fieldset class=\"fieldset-input is-1\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field is-single\" id=\"input-1\"><label for=\"field-1\">Solve using<\/label><div class=\"grid grid-cols-1\"><select id=\"field-1\" name=\"solve_using\"><option value=\"length\" selected>Pendulum length (L)<\/option><option value=\"period\">Oscillation period (T)<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><div class=\"field is-single has-term\" id=\"input-2\"><label for=\"field-2\">Pendulum length (L)<\/label><div class=\"term\">L<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"pendulum_length_l\" id=\"field-2\" aria-describedby=\"calc-info-2\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"e.g. 1\" min=\"0\" value=\"1\"\/><div class=\"grid grid-cols-1\"><select id=\"field-3\" name=\"unit\" aria-label=\"Unit\"><option value=\"m\" selected>m<\/option><option value=\"cm\">cm<\/option><option value=\"ft\">ft<\/option><option value=\"in\">in<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-2\">Distance from the pivot to the centre of the bob.<\/small><\/div><div class=\"field is-single has-term\" id=\"input-3\" hidden><label for=\"field-4\">Oscillation period (T)<\/label><div class=\"term\">T<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><input type=\"text\" name=\"oscillation_period_t\" id=\"field-4\" aria-describedby=\"calc-unit-4 calc-info-4\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"e.g. 2\" min=\"0\" value=\"2\"\/><div class=\"unit\" id=\"calc-unit-4\">s<\/div><small id=\"calc-info-4\">Time for one complete back-and-forth swing.<\/small><\/div><div class=\"field is-single has-term\" id=\"input-4\"><label for=\"field-5\">Mass of the bob (m) \u2014 optional<\/label><div class=\"term\">m<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"mass_of_the_bob_m_optional\" id=\"field-5\" aria-describedby=\"calc-info-5\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"e.g. 0.5\" min=\"0\" value=\"0.5\"\/><div class=\"grid grid-cols-1\"><select id=\"field-6\" name=\"unit\" aria-label=\"Unit\"><option value=\"kg\" selected>kg<\/option><option value=\"g\">g<\/option><option value=\"lb\">lb<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-5\">Optional: the mass does not change the period, it is only used to report it with your result.<\/small><\/div><div class=\"field is-single has-term\" id=\"input-5\"><label for=\"field-7\">Gravity (g)<\/label><div class=\"term\">g<\/div>  <div class=\"absolute bottom-0 left-16 top-8 w-2 h-0.5 bg-blue-500\"><\/div><div class=\"field-group\"><input type=\"text\" name=\"gravity_g\" id=\"field-7\" aria-describedby=\"calc-info-7\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"e.g. 9.81\" min=\"0\" value=\"9.81\"\/><div class=\"grid grid-cols-1\"><select id=\"field-8\" name=\"unit\" aria-label=\"Unit\"><option value=\"m\/s2\" selected>m\/s\u00b2<\/option><option value=\"ft\/s2\">ft\/s\u00b2<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-7\">9.81 m\/s\u00b2 on Earth, 1.62 m\/s\u00b2 on the Moon, 3.72 m\/s\u00b2 on Mars.<\/small><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"65863\">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> Pendulum Results<\/h3><div class=\"result-box\"><div class=\"field-result is-column\" id=\"output-1\"><span class=\"field-title\"><span>Period, frequency and pendulum length<\/span><\/span><span class=\"field-value\" id=\"result-1\"><\/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-2\"><span class=\"field-title\"><span>Formulas used<\/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><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=\"65863\" 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>Simple Pendulum 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\">\n\\[ T = 2\\pi\\sqrt{\\frac{L}{g}} \\qquad L = g\\left(\\frac{T}{2\\pi}\\right)^2 \\qquad f = \\frac{1}{T} \\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(T\\) \u2014 period of one full oscillation (s)<\/li>\n<li>\\(L\\) \u2014 length of the pendulum, from the pivot to the centre of the bob (m)<\/li>\n<li>\\(g\\) \u2014 gravitational acceleration (m\/s\u00b2, 9.81 on Earth)<\/li>\n<li>\\(f\\) \u2014 frequency in hertz (Hz), the number of swings per second<\/li>\n<\/ul>\n<p>The first formula gives the period from the length; the second is the same equation rearranged to find the length required for a desired period. Notice that the mass of the bob does not appear at all \u2014 it has no effect on the period of an ideal pendulum.<\/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>Simple Pendulum \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> a pendulum with a 1 m string swings on Earth, where \\(g = 9.81\\ \\text{m\/s}^2\\). What is its period?<\/p>\n<p>\\[ T = 2\\pi\\sqrt{\\frac{L}{g}} = 2\\pi\\sqrt{\\frac{1}{9.81}} = 2\\pi \\times 0.3193 \\approx 2.006\\ \\text{s} \\]<\/p>\n<p><strong>Result:<\/strong> the pendulum completes one full back-and-forth swing every 2.006 s, which corresponds to a frequency of \\(f = 1\/T \\approx 0.4985\\ \\text{Hz}\\), or about 29.9 swings per minute.<\/p>\n<p>Working in the opposite direction: to build a pendulum with a period of exactly 2 s on Earth you would need a length of \\(L = 9.81\\,(2\/2\\pi)^2 \\approx 0.994\\ \\text{m}\\).<\/p>\n<p>\n\r\n<\/section>\n<h2>How to Use the Calculator<\/h2>\n<ol>\n<li>In the <strong>Solve using<\/strong> dropdown, choose <em>Pendulum length (L)<\/em> if you know the length and want the period, or <em>Oscillation period (T)<\/em> if you want to find the length needed for a target period.<\/li>\n<li>Enter the known value: either <strong>Pendulum length (L)<\/strong> with its unit (m, cm, ft or in), or <strong>Oscillation period (T)<\/strong> in seconds. The calculator automatically shows only the relevant field.<\/li>\n<li>Optionally enter the <strong>Mass of the bob (m)<\/strong> in kg, g or lb. The mass does not change the period; it is only echoed back in the results so you have a complete record of your pendulum.<\/li>\n<li>Check <strong>Gravity (g)<\/strong>. The default 9.81 m\/s\u00b2 is standard for Earth; enter 1.62 for the Moon or 3.72 for Mars to see how the same pendulum behaves elsewhere. You can also switch the unit to ft\/s\u00b2.<\/li>\n<li>Read the results: the period in seconds, the frequency in Hz, the angular frequency \\(\\omega\\), swings per minute, and the length converted into m, cm, ft and in.<\/li>\n<\/ol>\n<h2>What Is a Simple Pendulum?<\/h2>\n<p>A simple pendulum is an idealized system: a point mass (the bob) hanging from a weightless, inextensible string attached to a fixed pivot. When the bob is pulled aside and released, it swings back and forth under gravity. Each complete cycle \u2014 out to one side, back through the middle, to the other side, and back again \u2014 is one oscillation, and its duration is the period \\(T\\).<\/p>\n<p>The key insight of the pendulum formula is what it does <em>not<\/em> contain. There is no mass term and no amplitude term. A 10 g bob and a 10 kg bob on a 1 m string swing with exactly the same period, and a small swing and a slightly larger small swing take the same time. This is why pendulums became the timekeeping heart of mechanical clocks for centuries: their tick is remarkably steady as the spring winds down and the amplitude gradually shrinks.<\/p>\n<p>The period grows with the square root of length, so quadrupling the length only doubles the period. It also shrinks with stronger gravity \u2014 the same 1 m pendulum that takes about 2 s on Earth would swing in a brisker 4.94 s period only under far weaker gravity: on the Moon, its period stretches to roughly 4.93 s because \\(g\\) there is just 1.62 m\/s\u00b2. If you want to explore the energy side of the motion \u2014 how potential energy at the top of the swing converts into kinetic energy at the bottom \u2014 try the <a href=\"https:\/\/wpcalc.com\/en\/physics\/conservation-of-energy-calculator\/\">Conservation of Energy<\/a> and <a href=\"https:\/\/wpcalc.com\/en\/physics\/kinetic-energy\/\">Kinetic Energy<\/a> calculators.<\/p>\n<h2>Assumptions and Limitations<\/h2>\n<ul>\n<li><strong>Small amplitudes only.<\/strong> The formula assumes the swing angle stays below roughly 15\u00b0 from vertical. At 15\u00b0 the true period is already about 0.5% longer than the formula predicts; at 60\u00b0 the error grows past 18%. For a rough rule, keep amplitudes small for clock-like accuracy.<\/li>\n<li><strong>Ideal string and pivot.<\/strong> The string is treated as massless and perfectly flexible, and the pivot as frictionless. In reality, a heavy string, a stiff rod, or pivot friction all shift the period slightly.<\/li>\n<li><strong>No air resistance or damping.<\/strong> Real pendulums lose a little energy each swing, which mainly reduces the amplitude over time; the period changes very little at first.<\/li>\n<li><strong>Point-mass bob.<\/strong> \\(L\\) is measured to the centre of mass of the bob, not to its top or bottom edge.<\/li>\n<li><strong>Uniform gravity.<\/strong> \\(g\\) is treated as constant over the pendulum's range of motion. On Earth, \\(g\\) varies slightly with latitude and altitude (from about 9.78 to 9.83 m\/s\u00b2), which changes the period of a long pendulum by a measurable amount.<\/li>\n<\/ul>\n<h2>Typical Pendulum Periods on Earth (g = 9.81 m\/s\u00b2)<\/h2>\n<table>\n<thead>\n<tr>\n<th>Length L<\/th>\n<th>Period T<\/th>\n<th>Swings per minute<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>0.25 m<\/td>\n<td>1.00 s<\/td>\n<td>59.7<\/td>\n<\/tr>\n<tr>\n<td>0.5 m<\/td>\n<td>1.42 s<\/td>\n<td>42.3<\/td>\n<\/tr>\n<tr>\n<td>1 m<\/td>\n<td>2.01 s<\/td>\n<td>29.9<\/td>\n<\/tr>\n<tr>\n<td>1.5 m<\/td>\n<td>2.46 s<\/td>\n<td>24.4<\/td>\n<\/tr>\n<tr>\n<td>2 m<\/td>\n<td>2.84 s<\/td>\n<td>21.2<\/td>\n<\/tr>\n<tr>\n<td>4 m<\/td>\n<td>4.01 s<\/td>\n<td>14.9<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Practical Tips<\/h2>\n<p>To design a pendulum clock tick of exactly 1 s per half-swing (the classic \"seconds pendulum\"), aim for a full period of 2 s, which needs a length of about 0.994 m on Earth. Since the period scales with \\(\\sqrt{L}\\), fine adjustments to the length give even finer control of the timing: shortening the string by 1% shortens the period by only 0.5%.<\/p>\n<p>The pendulum is also a classic tool for measuring local gravity. Time 20 or more full swings with a stopwatch, divide to get \\(T\\), measure \\(L\\) carefully to the bob's centre, and rearrange the formula to \\(g = 4\\pi^2 L \/ T^2\\). Timing many swings instead of one spreads your reaction-time error over the whole set and makes the result far more accurate. For related mechanics problems, see the <a href=\"https:\/\/wpcalc.com\/en\/physics\/atwood-machine-calculator\/\">Atwood Machine<\/a> and <a href=\"https:\/\/wpcalc.com\/en\/physics\/tension-in-ropes-calculator\/\">Tension in Ropes<\/a> calculators.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Calculate the period of a simple pendulum from its length and gravity, or find the length needed for a given period. Enter the known value and get period, frequency and swings per minute.<\/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":[62],"tags":[73],"class_list":["post-65863","post","type-post","status-publish","format-standard","hentry","category-physics","tag-mechanics"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/65863","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=65863"}],"version-history":[{"count":1,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/65863\/revisions"}],"predecessor-version":[{"id":65936,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/65863\/revisions\/65936"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=65863"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=65863"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=65863"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}