{"id":9607,"date":"2026-10-19T13:00:08","date_gmt":"2026-10-19T16:00:08","guid":{"rendered":"https:\/\/simcalculo.com\/pt-br\/roof-pitch-calculator\/"},"modified":"2026-10-19T13:00:08","modified_gmt":"2026-10-19T16:00:08","slug":"roof-pitch-calculator","status":"publish","type":"page","link":"https:\/\/simcalculo.com\/en\/roof-pitch-calculator\/","title":{"rendered":"Roof Pitch Calculator"},"content":{"rendered":"\n<p class=\"en-intro\">Find your roof pitch from rise and run, or convert a known pitch, angle or percentage. Get the answer in X:12, degrees and percent, with a scale diagram and optional rafter measurements.<\/p>\n\n<section class=\"rp-tool\" data-roof-tool aria-label=\"Roof pitch calculator\">\n<form id=\"rp-form\" novalidate>\n<label for=\"rp-mode\">What do you know?<\/label><select id=\"rp-mode\" name=\"mode\"><option value=\"measure\">Rise and horizontal run<\/option><option value=\"pitch\">Pitch (X in 12)<\/option><option value=\"angle\">Angle in degrees<\/option><option value=\"percent\">Slope percentage<\/option><\/select>\n<div data-mode=\"measure\" class=\"rp-grid\"><div><label for=\"rp-rise\">Vertical rise<\/label><div class=\"rp-input\"><input id=\"rp-rise\" name=\"rise\" inputmode=\"decimal\" autocomplete=\"off\" aria-describedby=\"rp-input-help\"><select name=\"riseUnit\" aria-label=\"Rise unit\"><option value=\"in\">in<\/option><option value=\"ft\">ft<\/option><option value=\"mm\">mm<\/option><option value=\"cm\">cm<\/option><option value=\"m\">m<\/option><\/select><\/div><\/div><div><label for=\"rp-run\">Horizontal run<\/label><div class=\"rp-input\"><input id=\"rp-run\" name=\"run\" inputmode=\"decimal\" autocomplete=\"off\" aria-describedby=\"rp-run-help\"><select name=\"runUnit\" aria-label=\"Run unit\"><option>in<\/option><option>ft<\/option><option>mm<\/option><option>cm<\/option><option>m<\/option><\/select><\/div><small id=\"rp-run-help\">Level distance, not the sloping length or full roof span.<\/small><\/div><\/div>\n<div data-mode=\"pitch\" hidden><label for=\"rp-pitch\">Rise per 12 horizontal units<\/label><div class=\"rp-input\"><input id=\"rp-pitch\" name=\"pitch\" inputmode=\"decimal\" autocomplete=\"off\"><span>in 12<\/span><\/div><\/div>\n<div data-mode=\"angle\" hidden><label for=\"rp-angle\">Roof angle<\/label><div class=\"rp-input\"><input id=\"rp-angle\" name=\"angle\" inputmode=\"decimal\" autocomplete=\"off\"><span>degrees<\/span><\/div><\/div>\n<div data-mode=\"percent\" hidden><label for=\"rp-percent\">Slope<\/label><div class=\"rp-input\"><input id=\"rp-percent\" name=\"percent\" inputmode=\"decimal\" autocomplete=\"off\"><span>%<\/span><\/div><\/div>\n<p id=\"rp-input-help\" class=\"rp-help\">Use a decimal point (6.5). Measurements also accept fractions, such as 6 1\/2. Rise and run may use different units.<\/p>\n<label class=\"rp-check\"><input type=\"checkbox\" name=\"dimensions\"> Estimate common rafter length and roof area<\/label>\n<div data-dimensions hidden class=\"rp-dimensions\"><p>Use the <strong>full horizontal run from the wall to the ridge<\/strong>. For a symmetrical gable roof, this is half the building span.<\/p><div class=\"rp-grid\"><div><label for=\"rp-dunit\">Dimension unit<\/label><select id=\"rp-dunit\" name=\"dimensionUnit\"><option value=\"ft\">Feet (decimal)<\/option><option value=\"m\">Meters<\/option><option value=\"in\">Inches<\/option><option value=\"cm\">Centimeters<\/option><option value=\"mm\">Millimeters<\/option><\/select><\/div><div><label for=\"rp-roofrun\">Full roof run<\/label><input id=\"rp-roofrun\" name=\"roofRun\" inputmode=\"decimal\" autocomplete=\"off\"><\/div><div><label for=\"rp-overhang\">Horizontal eave overhang<\/label><input id=\"rp-overhang\" name=\"overhang\" inputmode=\"decimal\" value=\"0\" autocomplete=\"off\"><\/div><div><label for=\"rp-rooflength\">Roof length along ridge (optional)<\/label><input id=\"rp-rooflength\" name=\"roofLength\" inputmode=\"decimal\" autocomplete=\"off\"><small>Include gable overhangs in this length, if needed.<\/small><\/div><div><label for=\"rp-sides\">Equal roof planes for area<\/label><select id=\"rp-sides\" name=\"sides\"><option value=\"2\">2 \u2014 symmetrical gable roof<\/option><option value=\"1\">1 \u2014 single roof plane<\/option><\/select><\/div><\/div><\/div>\n<p class=\"rp-error\" role=\"alert\" data-error hidden><\/p><div class=\"rp-actions\"><button type=\"submit\" class=\"rp-primary\">Calculate roof pitch<\/button><button type=\"button\" data-example>Use example<\/button><button type=\"reset\">Clear<\/button><\/div>\n<\/form><p data-status role=\"status\" aria-live=\"polite\" class=\"rp-help\"><\/p>\n<section data-result hidden tabindex=\"-1\" aria-label=\"Roof pitch result\"><div class=\"rp-answer\"><span>YOUR ROOF PITCH<\/span><h2 data-answer><\/h2><p data-answer-detail><\/p><\/div><div class=\"rp-result-grid\"><div><dl class=\"rp-metrics\"><div><dt>Angle<\/dt><dd data-angle><\/dd><\/div><div><dt>Slope<\/dt><dd data-percent><\/dd><\/div><div><dt>Length \/ area multiplier<\/dt><dd data-factor><\/dd><\/div><\/dl><p data-measured class=\"rp-help\"><\/p><p data-flat class=\"rp-note\" hidden>A 0:12 result describes a horizontal plane. It does not assess drainage or roofing suitability.<\/p><\/div><figure class=\"rp-diagram\"><svg viewBox=\"0 0 480 310\" role=\"img\" aria-labelledby=\"rp-svg-title\"><title id=\"rp-svg-title\">Roof rise and horizontal run<\/title><path data-fill fill=\"#ede7fb\"\/><path data-base fill=\"none\" stroke=\"#71809b\" stroke-width=\"2\" stroke-dasharray=\"5 5\"\/><path data-roof fill=\"none\" stroke=\"#59329b\" stroke-width=\"6\" stroke-linecap=\"round\"\/><text data-run-label text-anchor=\"middle\"\/><text data-rise-label\/><text data-angle-label\/><\/svg><figcaption>Rise is vertical. Run is horizontal. The slope is drawn to scale.<\/figcaption><\/figure><\/div>\n<div data-dimension-results hidden><h3>Estimated roof dimensions<\/h3><dl class=\"rp-dimension-metrics\"><\/dl><p class=\"rp-help\">Geometric lengths only. Ridge-board thickness, birdsmouth cuts, timber sizing and structural allowances are not included. Area excludes waste and overlaps.<\/p><\/div>\n<details class=\"rp-working\"><summary>Show the calculation<\/summary><div data-working><\/div><\/details><div class=\"rp-actions rp-export\"><button type=\"button\" data-copy>Copy result<\/button><button type=\"button\" data-csv>Download CSV<\/button><button type=\"button\" data-print>Print result<\/button><\/div><\/section>\n<\/section>\n\n\n\n<article class=\"en-editorial\">\n<h2>How to calculate roof pitch<\/h2>\n<ol><li>Measure a level <strong>horizontal run<\/strong> under the roof slope.<\/li><li>Measure the <strong>vertical rise<\/strong> across that same horizontal distance.<\/li><li>Enter both measurements and their units. A 12-inch level is convenient, but any positive run works.<\/li><li>Select <strong>Calculate roof pitch<\/strong> to see the X:12 ratio, angle, percentage and multiplier.<\/li><\/ol>\n<p>For example, a roof that rises 6 inches over a horizontal distance of 12 inches has a <strong>6:12 pitch, a 26.57\u00b0 angle and a 50% slope<\/strong>. Six inches of rise over one foot of run gives exactly the same answer.<\/p>\n<h2>Roof pitch formulas<\/h2>\n<p>This tool uses \u201cpitch\u201d in the common X:12 sense: vertical rise per 12 units of horizontal run. Older references sometimes use pitch to mean rise divided by the full span; that is a different ratio.<\/p>\n<ul><li><code>Slope ratio = rise \u00f7 run<\/code><\/li><li><code>Pitch in 12 = (rise \u00f7 run) \u00d7 12<\/code><\/li><li><code>Angle = atan(rise \u00f7 run) \u00d7 180 \u00f7 \u03c0<\/code><\/li><li><code>Slope percentage = (rise \u00f7 run) \u00d7 100<\/code><\/li><li><code>Rafter multiplier = \u221a(1 + (rise \u00f7 run)\u00b2)<\/code><\/li><\/ul>\n<p>Measurements are converted to the same unit before calculation. Results are rounded for display; calculations use unrounded values.<\/p>\n<h2>Common roof pitches and angles<\/h2>\n<table><caption>Geometric conversions, not roofing-material recommendations<\/caption><thead><tr><th scope=\"col\">Pitch<\/th><th scope=\"col\">Angle<\/th><th scope=\"col\">Slope<\/th><\/tr><\/thead><tbody>\n<tr><td>1:12<\/td><td>4.76\u00b0<\/td><td>8.33%<\/td><\/tr><tr><td>2:12<\/td><td>9.46\u00b0<\/td><td>16.67%<\/td><\/tr><tr><td>3:12<\/td><td>14.04\u00b0<\/td><td>25%<\/td><\/tr><tr><td>4:12<\/td><td>18.43\u00b0<\/td><td>33.33%<\/td><\/tr><tr><td>5:12<\/td><td>22.62\u00b0<\/td><td>41.67%<\/td><\/tr><tr><td>6:12<\/td><td>26.57\u00b0<\/td><td>50%<\/td><\/tr><tr><td>7:12<\/td><td>30.26\u00b0<\/td><td>58.33%<\/td><\/tr><tr><td>8:12<\/td><td>33.69\u00b0<\/td><td>66.67%<\/td><\/tr><tr><td>9:12<\/td><td>36.87\u00b0<\/td><td>75%<\/td><\/tr><tr><td>10:12<\/td><td>39.81\u00b0<\/td><td>83.33%<\/td><\/tr><tr><td>12:12<\/td><td>45\u00b0<\/td><td>100%<\/td><\/tr><tr><td>18:12<\/td><td>56.31\u00b0<\/td><td>150%<\/td><\/tr><tr><td>24:12<\/td><td>63.43\u00b0<\/td><td>200%<\/td><\/tr><\/tbody><\/table>\n<h2>Estimate common rafter length and roof area<\/h2>\n<p>Once the pitch is known, enable the dimension estimate and enter the <strong>full horizontal run from the wall to the ridge<\/strong>. On a symmetrical gable roof, run is half the horizontal building span. Do not enter the full span as the run.<\/p>\n<p>For a 6:12 roof with a 10-foot run, the rise is 5 feet and the common rafter\u2019s geometric length is <strong>11.1803 feet<\/strong> before overhang. A 1-foot horizontal eave overhang increases the geometric sloping length to <strong>12.2984 feet<\/strong>.<\/p>\n<p>For area, also enter the roof length along the ridge. The calculator multiplies the sloping length by this roof length and by one or two equal roof planes. The two-plane option assumes a symmetrical gable roof with matching slopes and runs. It does not model hips, valleys, dormers or irregular roof sections. No waste factor, roofing overlap or trim allowance is added.<\/p>\n<h2>What this result can tell you<\/h2>\n<p>This is a geometry calculator. It does not determine a safe roof pitch, a minimum pitch for a particular covering, timber sizes, loads, code compliance or cut dimensions. Roofing suitability depends on the specific product instructions, assembly and applicable local requirements.<\/p>\n<p>Rafter lengths exclude ridge-board thickness and birdsmouth adjustments. A multiplier applied to a horizontal footprint gives a sloped area only when that footprint belongs to the matching uniform roof plane. Do not use a diagram or a rounded result as a construction drawing.<\/p>\n<h2>Calculation reference<\/h2>\n<p>The rise\/run, pitch conversion and common-rafter geometry follow the right-triangle methods illustrated in the <a href=\"https:\/\/www.johnsonlevel.com\/Content\/files\/manuals\/CALC-1500Manual.pdf\" target=\"_blank\" rel=\"noopener\">Johnson Level CALC-1500 instruction manual<\/a>, pages 16\u201317. This calculator is independently developed by SimC\u00e1lculo.<\/p>\n<\/article>\n\n","protected":false},"excerpt":{"rendered":"<p>Find your roof pitch from rise and run, or convert a known pitch, angle or percentage. Get the answer in X:12, degrees and percent,&hellip;<\/p>\n","protected":false},"author":0,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-9607","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/simcalculo.com\/pt-br\/wp-json\/wp\/v2\/pages\/9607","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/simcalculo.com\/pt-br\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/simcalculo.com\/pt-br\/wp-json\/wp\/v2\/types\/page"}],"replies":[{"embeddable":true,"href":"https:\/\/simcalculo.com\/pt-br\/wp-json\/wp\/v2\/comments?post=9607"}],"version-history":[{"count":0,"href":"https:\/\/simcalculo.com\/pt-br\/wp-json\/wp\/v2\/pages\/9607\/revisions"}],"wp:attachment":[{"href":"https:\/\/simcalculo.com\/pt-br\/wp-json\/wp\/v2\/media?parent=9607"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}