From this site

One project, every trade

Each calculator adds its lines to a single estimate — consolidated BOM, schedule and cash-flow included.

Open My Project →

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 for United States against IRC 2024, and every formula 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 against IRC 2024. The market selector changes both the units and the code cited.

Add the equipment this sizes

This result is a specification — 26.565 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 — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

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)

Your workspace

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.