Roof Pitch Calculator

Convert between roof pitch, degrees, and percentage. Calculate rise and run.

Input Mode

Rise (per 12 inches of run)

Area Multiplier: multiply your floor footprint by this number to get actual roof surface area.

DIY difficulty

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›Working at height is the #1 cause of serious DIY injuries
›Improper flashing causes leaks that damage the structure
›Most municipalities require licensed contractors for roofing permits

How to use the roof pitch calculator

Enter your pitch in X:12 format — a 6:12 pitch rises 6 inches for every 12 inches of horizontal run.
Or enter degrees if you measured the angle directly, or percentage if you're working from engineering drawings.
Read the converted values: the calculator shows all three formats plus the roof area multiplier.
Use the multiplier to convert your flat (footprint) area to actual roof surface area for ordering shingles or metal roofing.

Common uses

Converting pitch to degrees for rafter cuts and templates
Calculating actual roof area for shingle and underlayment orders
Verifying slope meets building code for your roofing material

Frequently asked questions

What is a 4:12 roof pitch?

A 4:12 pitch rises 4 inches for every 12 inches of horizontal run. That's a 18.4° angle and a fairly gentle slope — common on ranch-style homes.

What's the minimum roof pitch for shingles?

Most asphalt shingle manufacturers require at least a 4:12 pitch. Low-slope roofs (2:12 to 4:12) need special low-slope shingles or a different roofing system entirely.

How do I measure my existing roof pitch?

Hold a level horizontally against the roof surface. Measure 12 inches out from the wall (the run), then measure the vertical distance up to the underside of the level (the rise). That rise/12 is your pitch.

What is the most common residential roof pitch in the US?

The most common pitch is 4:12 to 6:12. Ranch homes are often 3:12–4:12; colonials and capes typically run 8:12–12:12. Anything above 12:12 is considered a steep roof.

How do I find my roof pitch without going on the roof?

From the attic, hold a level horizontally at the underside of a rafter. Measure 12 inches along the level, then measure vertically up to the rafter. That vertical measurement in inches is your pitch (rise).

Common mistakes to avoid

✕Using flat footprint instead of actual roof area — a 6:12 pitch roof has ~12% more actual surface than its footprint.
✕Not calculating valleys, dormers, and hips separately — the pitch multiplier applies to simple gable sections only.
✕Ordering low-slope shingles without checking minimum pitch — standard architectural shingles require at least 4:12.
✕Buying shingles from different production runs — shingle color varies between batches. Order all material at once.

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Not sure whether to DIY this project?

Read our project-by-project guide on when to hire a contractor vs. do it yourself.

Read the guide →

About this calculator

Enter pitch as X:12, an angle in degrees, or a percentage to instantly get all other values. Also calculates the roof area multiplier factor for material estimates.

All results are estimates. Verify quantities with your local supplier and confirm measurements before purchasing materials. Requirements vary by region and project type.

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