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Roofing

Roof Pitch Calculator USA 2026

Convert roof rise-over-run into a pitch multiplier and angle in degrees, so you can size shingles and underlayment.

Reviewed by BuildMate Editorial Team Construction Researchers Updated March 2026 2 min read Fact-checked

Used by

250,000+ homeowners

Avg. time

~15 seconds

Updated

2026

Accuracy

Pro estimation

Works on: Desktop Tablet Mobile No registration required
Unit system

Enter your measurements

Results

Pitch

6/12

Pitch multiplier

1.118

Angle

26.6°

Calculation steps
  1. 1.Multiplier = √(6² + 12²) ÷ 12 = √180 ÷ 12 = 1.118
  2. 2.Angle = atan(6/12) = 26.57°

Includes a standard waste allowance. Verify with your supplier before ordering.

Stored on this device — no account needed.

What this calculator does

Converts roof footprint and pitch into the total roof area, number of shingle bundles and underlayment rolls you'll need.

When to use it

  • Estimating a re-roof or new-build shingle order.
  • Sizing ice-and-water shield and drip edge.
  • Comparing shingle vs. metal cost per square.

Common mistakes

  • Using floor area instead of the pitched roof area.
  • Forgetting the starter course and ridge cap bundles.
  • Ignoring valley and hip waste — always add 10%.

Pro tips

  • 3 bundles = 1 square (100 sq ft) for architectural shingles.
  • Always replace flashing when re-roofing.
  • Check with your local code for ice-and-water shield requirements.
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Disclaimer: Estimates based on 2026 RSMeans USA data. Actual quantities vary by site conditions, waste and installer practices. Verify with your supplier or contractor before ordering.

How it works

  1. 1Enter rise per 12" of run (e.g. 6 for a 6/12 pitch).
  2. 2We output the pitch multiplier and roof angle.

Formula

Multiplier = √(rise² + 12²) ÷ 12 → Angle = atan(rise ÷ 12)

Worked example

6/12 pitch → √(36+144)/12 = 1.118 multiplier, 26.6° angle.

Frequently asked questions

What's a walkable pitch?

Up to 6/12 is safely walkable; steeper needs roof jacks.

Standard pitch multipliers?

3/12=1.031, 4/12=1.054, 6/12=1.118, 8/12=1.202, 12/12=1.414.

Is the Roof Pitch Calculator free to use?

Yes — every BuildMate calculator is 100% free, requires no signup and works offline once the page has loaded.

How accurate are these estimates?

Formulas follow 2026 industry standards (RSMeans, ICC and manufacturer specs). Real-world results vary by site conditions, waste and installer practices — always get 2–3 written quotes from licensed pros before committing.

Can I save my calculation?

Yes. Hit the Save button after you run an estimate — it's stored on this device (no account needed) and you can access it anytime from the Saved drawer.

Can I compare two projects side-by-side?

Yes. Add estimates to Compare and open the Compare drawer to see them side-by-side, then use Download PDF or Email to share the comparison.

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