Conversion

Roof Pitch to Degrees Conversion Chart

A complete reference table for converting roof pitch (x:12 ratio) to degrees, percentage slope, and pitch factor — plus the formula to convert any pitch you encounter.

The conversion formula

Roof pitch in the US is expressed as x:12 — the number of inches of rise per 12 inches of run. To convert to degrees:

Degrees = arctan(x ÷ 12) × (180 ÷ π)

To convert degrees back to x:12 pitch:

x = tan(degrees) × 12

To convert x:12 to percentage slope:

% slope = (x ÷ 12) × 100

Complete conversion table

Pitch (x:12)	Degrees	% slope	Pitch factor	Category
1:12	4.76°	8.3%	1.003	Flat
2:12	9.46°	16.7%	1.014	Low slope
3:12	14.04°	25.0%	1.031	Low slope
4:12	18.43°	33.3%	1.054	Conventional
5:12	22.62°	41.7%	1.083	Conventional
6:12	26.57°	50.0%	1.118	Conventional ★
7:12	30.26°	58.3%	1.158	Conventional
8:12	33.69°	66.7%	1.202	Conventional
9:12	36.87°	75.0%	1.250	Conventional
10:12	39.81°	83.3%	1.302	Steep
11:12	42.51°	91.7%	1.357	Steep
12:12	45.00°	100.0%	1.414	Steep
14:12	49.40°	116.7%	1.537	Very steep
16:12	53.13°	133.3%	1.667	Very steep

★ 6:12 is the most common residential pitch in the US. Pitch factor = √((x/12)² + 1) — multiply your flat roof footprint by this number to get the true sloped surface area for material ordering.

Worked examples

Example 1 — x:12 to degrees

8:12 pitch → arctan(8 ÷ 12) = arctan(0.667) = 33.69°

Example 2 — degrees to x:12

30° → tan(30°) × 12 = 0.577 × 12 = 6.93:12 ≈ 7:12

Example 3 — pitch factor for material ordering

6:12 pitch, 2,000 sq ft footprint → 2,000 × 1.118 = 2,236 sq ft of roofing material

Roofing material by pitch

Pitch range	Compatible materials
0:12 – 2:12	TPO, EPDM, PVC membrane only
2:12 – 4:12	Modified bitumen, some metal panels
4:12 – 9:12	Asphalt shingles, metal, clay/concrete tile, wood shakes
10:12 – 12:12	All of above — safety equipment required for installation
Over 12:12	Metal, slate, specialty systems — structural engineer recommended

Minimum pitch for standard asphalt shingles is 2:12 with double underlayment, 4:12 for standard installation per most manufacturer warranties. Always check the specific manufacturer's requirements before specifying materials.

Convert any pitch instantly

Enter rise and run, degrees, or x:12 ratio — get all conversions, rafter length, and true roof area in one step.

Use the Roof Pitch Calculator →

FAQ

How do I convert roof pitch to degrees?

Use arctan(rise ÷ 12) × (180 ÷ π). For a 6:12 pitch: arctan(6 ÷ 12) = arctan(0.5) = 26.57°. Most scientific calculators have an arctan (tan⁻¹) button. The roof pitch calculator on this site handles the conversion instantly.

What is a 4:12 pitch in degrees?

A 4:12 pitch equals 18.43°. Use arctan(4 ÷ 12) = arctan(0.333) = 18.43°. This is a low-slope conventional pitch commonly used on ranch-style homes and low-profile additions.

What is a 6:12 pitch in degrees?

A 6:12 pitch equals 26.57°. This is the most common residential roof pitch in the US — it sheds water well, supports all standard roofing materials, and is safe to walk on without special equipment.

How do I convert degrees back to x:12 pitch?

Use tan(degrees) × 12. For 30°: tan(30°) = 0.577 × 12 = 6.93, so approximately 7:12. This is exact: a 30° roof is a 6.928:12 pitch.

What angle is a 12:12 pitch?

A 12:12 pitch is exactly 45° — the roof rises as much as it runs horizontally. This is the steepest common residential pitch. Above 12:12 produces angles greater than 45°, which are considered very steep or specialty pitches.