Roof Pitch Measurement Diagram

Visual guide to understanding how roof pitch is measured — rise vertically, run horizontally.

Diagram showing how roof pitch is measured: the vertical rise over a horizontal run of 12 inches, with the angle formed at the eave — Roof pitch = rise ÷ run (per 12 inches of horizontal distance)

What Is Roof Pitch?

Roof pitch describes the steepness of a roof as a ratio of rise over run. In the US, run is standardized at 12 inches, so a 6/12 pitch means the roof rises 6 inches for every 12 inches of horizontal distance.

How to Read the Diagram

Rise (blue, vertical) — the vertical height gained over the run distance
Run (green, horizontal) — always 12 inches in standard US notation
Angle — the angle formed between the roof surface and the horizontal

Common Roof Pitches

Pitch	Rise (inches)	Angle (degrees)	Typical Use
3/12	3	14°	Low-slope / shed
4/12	4	18°	Ranch homes
6/12	6	27°	Standard residential
8/12	8	34°	Steeper residential
12/12	12	45°	Steep / A-frame

Use the roof pitch calculator to convert between pitch, angle, and rafter length.

Source

International Residential Code (IRC) — Roofing

Use the Calculator

This diagram is part of the Roof Pitch Calculator.

Open Roof Pitch Calculator →