Roofing & Exterior
Convert one verified roof slope into equivalent X/12 pitch, rise-to-run ratio, angle, percent slope and pitch multiplier without mixing roof geometry with material purchasing.
Change the defaults to match your project and the product you plan to buy.
Carry the measurement forward
The visual is proportional for planning only; the numeric result is the source of truth.
Use this pitch in Roofing CalculatorProject result
Compare the same roof slope as X/12 pitch, ratio, angle, percent slope and multiplier, then carry the pitch into the Roofing Calculator.
At a glance
Planning estimate only. Verify product coverage, package size, supplier specifications and project requirements before purchasing.
Budget scenario
Use a current supplier subtotal or reuse a priced calculator result, then add optional delivery, tax and contingency. Home Measure Lab does not fetch or guess live prices.
Enter a current supplier subtotal or reuse a priced calculator result.
Budget values are local planning inputs, not live quotes. Verify tax treatment, delivery, labor and supplier pricing before purchasing.
Choose the right tool
You need to convert one verified roof inclination between X/12 pitch, rise/run ratio, degrees, slope percent and pitch multiplier.
Use Roof Area for simple-gable surface geometry or Roofing Calculator for material quantities; this tool does not select a roof system or minimum permitted slope.
Methodology
rise ÷ horizontal run
For X/12 pitch, divide X by 12.
atan(rise ÷ run)
Convert the arctangent from radians to degrees.
(rise ÷ run) × 100
A 6/12 roof has a 50% slope.
√(1 + (rise ÷ run)²)
Converts horizontal plan length/area into sloped length/area when the geometry model is appropriate.
Use a pitch value from construction documents, a trustworthy measurement record, safe ground/attic geometry or a qualified measurement source. For rise-and-run mode, both measurements must use the same unit and the run must be horizontal. Do not measure the sloped rafter length and enter it as run.
Pitch is only one geometric input. Roofing products can have manufacturer minimum slopes, special underlayment requirements and project-specific code or assembly requirements. Verify those requirements separately before selecting materials or installation details.
Reference
| Pitch | Angle | Slope | Multiplier |
|---|---|---|---|
| 1/12 | 4.76° | 8.3% | 1.0035 |
| 2/12 | 9.46° | 16.7% | 1.0138 |
| 3/12 | 14.04° | 25.0% | 1.0308 |
| 4/12 | 18.43° | 33.3% | 1.0541 |
| 5/12 | 22.62° | 41.7% | 1.0833 |
| 6/12 | 26.57° | 50.0% | 1.1180 |
| 7/12 | 30.26° | 58.3% | 1.1577 |
| 8/12 | 33.69° | 66.7% | 1.2019 |
| 9/12 | 36.87° | 75.0% | 1.2500 |
| 10/12 | 39.81° | 83.3% | 1.3017 |
| 11/12 | 42.51° | 91.7% | 1.3566 |
| 12/12 | 45.00° | 100.0% | 1.4142 |
| 13/12 | 47.29° | 108.3% | 1.4743 |
| 14/12 | 49.40° | 116.7% | 1.5366 |
| 15/12 | 51.34° | 125.0% | 1.6008 |
| 16/12 | 53.13° | 133.3% | 1.6667 |
| 17/12 | 54.78° | 141.7% | 1.7341 |
| 18/12 | 56.31° | 150.0% | 1.8028 |
Questions
A 6/12 pitch is about 26.565 degrees because atan(6 ÷ 12) ≈ 26.565°.
They describe the same inclination in different formats. Pitch is commonly written X/12, while slope may be expressed as a ratio, percentage or angle.
Yes for a compatible simple plan geometry. Use Roof Area Calculator for a simple gable footprint, and use measured roof planes for complex roofs.
No. Use safer existing measurements, plans, ground/attic methods where appropriate, or qualified measurement when roof access would create a fall hazard.
Estimate simple-gable roof square footage and roofing squares from horizontal footprint, overhang and roof pitch before material-specific waste or packaging.
Open calculator → Roofing & ExteriorEstimate simple-gable or measured roof area, roofing squares, shingle bundles, underlayment rolls, starter, ridge cap, drip edge and roofing nails with editable product coverage.
Open calculator → Roofing & ExteriorEstimate roofing squares and shingle bundles from measured roof area, waste allowance and actual bundle coverage.
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