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Roof Pitch to Angle Calculator

Convert a roof pitch (rise per 12 in of run) into its equivalent angle in degrees and slope percent.

Computed in your browser — nothing you enter is uploaded. Figures are presented in United States units and terminology, and each formula’s basis is cited under regulatory standards below.

Last verified 2026-08-25 · v1.0.0

Market
Imperial · sales tax

Roof angle

26.57 degrees

High confidence
Slope percent
50 %

For the dimensions entered, expect a roof angle of 26.6 degrees. Set for United States. The market selector changes the units and the trade terminology; any standard behind the formula is cited under sources.

Add the equipment this sizes

This result is a specification — 26.57 degrees — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — a confirmed fix gets a permanent check of its own, so the same mistake cannot come back.

Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.

Regulatory standards & verification citations

  • Roofing pitch is conventionally expressed as rise per 12 in of run (e.g. '6/12'); angle in degrees = arctangent(rise / 12)

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Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

Why is roof pitch expressed as X/12 instead of degrees?
It's a long-standing North American roofing and carpentry convention tied to the framing square (a common layout tool marked in inches) — '6/12' tells a framer directly how to set the square, which is faster on the job site than working in degrees.
What pitch is considered 'low slope' vs 'steep'?
Roughly under 4/12 is often called low-slope (needing different roofing materials/methods), 4/12 to 9/12 is a common standard range, and above 9/12 is generally considered steep, sometimes requiring roof harnesses for safe installation.
Does roof pitch affect how much material I need?
Yes — a steeper pitch means more actual roof surface area for the same footprint, since the shingles/material cover the sloped surface, not the flat plan area. Check the Roofing Shingle Calculator, which accounts for this.