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Roof Pitch Chart: Pitch to Degrees Conversion
Quick answer: To convert roof pitch to degrees, take the arctangent of rise ÷ 12. A 6/12 pitch = arctan(6/12) = 26.6°, which is a 50% slope.
Roof pitch is written as rise-over-run (like 6/12), but you often need it as an angle in degrees, a percentage slope, or a pitch multiplier for estimating roof area. This chart gives all four for every common pitch.
Full roof pitch conversion chart
Every common roof pitch converted to degrees, slope percentage, and rafter multiplier. Low slopes (under 3:12) are listed in half-pitch increments because that is the range where small differences change what roofing material you are allowed to use.
| Pitch (rise/12) | Angle (degrees) | Slope (%) | Rafter multiplier |
|---|---|---|---|
| 0.5/12 | 2.39° | 4.2% | 1.001 |
| 1/12 | 4.76° | 8.3% | 1.003 |
| 1.5/12 | 7.13° | 12.5% | 1.008 |
| 2/12 | 9.46° | 16.7% | 1.014 |
| 2.5/12 | 11.77° | 20.8% | 1.021 |
| 3/12 | 14.04° | 25.0% | 1.031 |
| 3.5/12 | 16.26° | 29.2% | 1.042 |
| 4/12 | 18.43° | 33.3% | 1.054 |
| 4.5/12 | 20.56° | 37.5% | 1.068 |
| 5/12 | 22.62° | 41.7% | 1.083 |
| 5.5/12 | 24.62° | 45.8% | 1.100 |
| 6/12 | 26.57° | 50.0% | 1.118 |
| 6.5/12 | 28.44° | 54.2% | 1.137 |
| 7/12 | 30.26° | 58.3% | 1.158 |
| 7.5/12 | 32.01° | 62.5% | 1.179 |
| 8/12 | 33.69° | 66.7% | 1.202 |
| 9/12 | 36.87° | 75.0% | 1.250 |
| 10/12 | 39.81° | 83.3% | 1.302 |
| 11/12 | 42.51° | 91.7% | 1.357 |
| 12/12 | 45.00° | 100.0% | 1.414 |
| 13/12 | 47.29° | 108.3% | 1.474 |
| 14/12 | 49.40° | 116.7% | 1.537 |
| 15/12 | 51.34° | 125.0% | 1.601 |
| 16/12 | 53.13° | 133.3% | 1.667 |
| 18/12 | 56.31° | 150.0% | 1.803 |
| 20/12 | 59.04° | 166.7% | 1.944 |
| 24/12 | 63.43° | 200.0% | 2.236 |
Angle = arctan(rise ÷ 12). Multiplier = √(rise² + 12²) ÷ 12. Values are exact to the decimal shown, not rounded estimates.
Reverse chart: degrees to roof pitch
If you measured an angle with a phone level or a digital inclinometer and need the pitch, work from this direction instead.
| Angle | Exact pitch | Nearest standard pitch |
|---|---|---|
| 5° | 1.05/12 | 1/12 |
| 10° | 2.12/12 | 2/12 |
| 15° | 3.22/12 | 3/12 |
| 20° | 4.37/12 | 4.5/12 |
| 25° | 5.60/12 | 5.5/12 |
| 30° | 6.93/12 | 7/12 |
| 35° | 8.40/12 | 8.5/12 |
| 40° | 10.07/12 | 10/12 |
| 45° | 12.00/12 | 12/12 |
| 50° | 14.30/12 | 14.5/12 |
| 55° | 17.14/12 | 17/12 |
| 60° | 20.78/12 | 21/12 |
Roofs are framed to whole and half pitches, so a measured 27° almost certainly means a 6:12 roof that has settled slightly — not a 6.1:12 roof.
What the pitch multiplier is for
This is the column most people actually need, and the one most charts leave out.
The footprint of your roof is not its surface area. A roof covering a 40 × 30 ft footprint has 1,200 sq ft of ground beneath it, but the sloped surface you have to buy shingles for is larger — and the steeper the roof, the larger it gets.
Roof surface area = footprint area × pitch multiplier.
So that same 1,200 sq ft footprint needs:
- 4:12 pitch → 1,200 × 1.054 = 1,265 sq ft of roofing
- 6:12 pitch → 1,200 × 1.118 = 1,342 sq ft
- 9:12 pitch → 1,200 × 1.250 = 1,500 sq ft
- 12:12 pitch → 1,200 × 1.414 = 1,697 sq ft
Ordering off the footprint instead of the sloped area is the single most common way people end up short on a roofing order — and at 12:12 it is a 41% shortfall.
Pitch categories and what they mean for materials
Pitch is not just a number; it determines what you are permitted to install.
- Flat / low slope (under 2:12) — shingles are not permitted. Requires a membrane system such as TPO, EPDM, or modified bitumen.
- Low slope (2:12 to 4:12) — asphalt shingles are allowed from 2:12 but require a doubled underlayment below 4:12 under IRC R905.2.2. Check this before ordering.
- Conventional (4:12 to 9:12) — the standard residential range. All common roofing materials apply, and the roof is generally walkable.
- Steep (above 9:12) — no longer safely walkable; requires roof jacks or staging, which raises labour cost significantly. Above 12:12 many roofers price as a specialty job.
Local codes amend these thresholds. Confirm with your building department before buying material for anything under 4:12.
How the conversion works
Pitch is rise over run. The angle is the arctangent of that ratio: for 6/12, arctan(6÷12) = arctan(0.5) = 26.57°. The percentage slope is just rise ÷ run × 100 (6/12 = 50%). The pitch multiplier is the length of the sloped surface per unit of horizontal run — the square root of (rise² + run²) ÷ run.
Measure your own pitch
To find your pitch, hold a level horizontally against the roof, measure 12 inches along it, then measure straight down to the roof surface — that drop in inches is your rise over 12. Or use the tool:
Looking for something slightly different?
We keep four separate roof-pitch pages because people arrive with four different questions. If this is not the one you wanted:
- Roof Pitch Calculator — enter a rise and run and get pitch, degrees and the rafter multiplier.
- Slope Calculator — work in slope percentage, grade or 1:X ratio — also covers ADA ramps and drain pipe falls.
- Roof Pitch Guide — the long-form explainer: what pitch is, three ways to measure it, and why it changes your material order.
Frequently asked questions
What is 6/12 pitch in degrees?
26.57°, with a pitch multiplier of 1.118.
What is 4/12 pitch in degrees?
18.43°, multiplier 1.054.
What does the pitch multiplier do?
It converts flat footprint area into true sloped roof area — multiply footprint by the multiplier for material estimates.