Roof Cost Calculator › Guides › Roof pitch multiplier chart (0/12 to 12/12)
Multiply the flat footprint of your roof by the pitch multiplier to get the real sloped area. A chart for 0/12 to 12/12 with angles and a 2,000 sq ft example.
Pitch is the rise in inches per 12 inches of horizontal run. The sloped area is the flat (plan) area times the pitch multiplier = √(1 + (rise ÷ 12)²). This is plain geometry (Pythagoras), values are rounded to three decimals.
| Pitch | Angle | Multiplier | 2,000 sq ft footprint becomes |
|---|---|---|---|
| 0/12 | 0.0° | 1.000 | 2,000 |
| 1/12 | 4.8° | 1.003 | 2,007 |
| 2/12 | 9.5° | 1.014 | 2,028 |
| 3/12 | 14.0° | 1.031 | 2,062 |
| 4/12 | 18.4° | 1.054 | 2,108 |
| 5/12 | 22.6° | 1.083 | 2,167 |
| 6/12 | 26.6° | 1.118 | 2,236 |
| 7/12 | 30.3° | 1.158 | 2,315 |
| 8/12 | 33.7° | 1.202 | 2,404 |
| 9/12 | 36.9° | 1.250 | 2,500 |
| 10/12 | 39.8° | 1.302 | 2,603 |
| 11/12 | 42.5° | 1.357 | 2,713 |
| 12/12 | 45.0° | 1.414 | 2,828 |
Use the footprint including overhangs. Add dormers and other features separately, then add a waste allowance before ordering materials. Our calculator's adjusted area works the same way.
Measure from inside the attic, or use a pitch app on a ladder at the gable end. Do not walk on a steep roof without fall protection.
Only if every plane has the same pitch. Work out planes with different pitches separately.
Last checked: 29 October 2026.