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DatumSpot

Roof Pitch Converter

Convert a roof slope between rise-in-12 (like 6:12), angle in degrees, and percent grade.

Rise per 12" of run. Accepts 6, 7.5, or a ratio like 6:12 or 6/16.

Pitch (rise-in-12)6:12
Angle26.6°
Grade (slope)50%

Pitch, angle, and grade

Roof slope is usually written as rise-in-12 — a 6:12 roof climbs 6" of rise for every 12" of horizontal run. That same slope can be expressed as an angle from horizontal or a percent grade:

  • Angle = atan(rise ÷ run) — a 6:12 roof is about 26.6°.
  • Grade = rise ÷ run × 100 — a 6:12 roof is a 50% grade.
  • A 12:12 roof is exactly 45° and 100%.

Enter a pitch as a single number (6, 7.5) or a ratio (6:12, even an off-12 run like 6/16), or switch the input to degrees or percent to convert the other way.

Frequently asked questions

What does a 6:12 roof pitch mean?

The roof rises 6 inches vertically for every 12 inches of horizontal run. That works out to about 26.6° from horizontal and a 50% grade.

How do I convert roof pitch to degrees?

Take the arctangent of rise divided by run. For x-in-12 that is atan(x ÷ 12): a 4:12 roof is about 18.4°, 6:12 is about 26.6°, and 12:12 is exactly 45°.

What is the difference between pitch, angle, and grade?

Pitch is the rise-in-12 ratio (like 6:12), angle is that slope in degrees, and grade is rise ÷ run as a percent. A 6:12 roof is 26.6° and 50%; a 12:12 roof is 45° and 100%.

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