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Geometry Basics

Roof Pitch Calculator

Enter roof rise and run to calculate pitch, angle, and a roof area multiplier.

Last updated: May 2026

Unit system Switch between U.S. customary and metric units. Your choice is remembered on other calculators.

Roof slope measurements

Pitch is commonly shown as inches of rise per 12 inches of run. Measure rise and run on the same unit scale.

Visual guide

Which measurement goes where?

Rise is measured vertically. Run is measured horizontally. Roof pitch is commonly expressed as inches of rise per 12 inches of run.

in
in

Buying and sizing notes

How to use this estimate

What this includes

  • The required inputs shown on this page
  • common planning assumptions
  • optional advanced adjustments where provided

What it does not include

  • site-specific professional design
  • local code approval
  • manufacturer-specific requirements
  • installation quality

Common mistakes

  • Leaving a required input at the default when your situation is different
  • ignoring product labels or ratings
  • treating the estimate as an exact final answer

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