Roof Pitch & Slope Converter
Translate between architectural pitch (rise in 12), degrees, and percent grade. Built for PEMB roof notes, structural models, and drainage conversations that mix units.
Slope Converter
Type in ANY field below. The others update instantly.
Pitch, Degrees, and Percent Grade
Architects write “4:12,” engineers model degrees, and civil notes say “2%.” They describe the same triangle: tan(θ) = rise/run. Enter any one field and the others update so roof notes, Tekla work points, and gutter fall all stay consistent.
How to use this converter
- Type architectural pitch as the rise on 12 (e.g., 0.5 for ½:12, 4 for 4:12).
- Or enter degrees or percent grade — the remaining fields recalculate immediately.
- Use Reset when switching between roof and ramp problems so stale values do not linger.
Steel building slopes
PEMB roofs often run ¼:12 to 1:12. Screw-down PBR commonly sits near ½:12–1:12; standing seam can go flatter when clips allow thermal movement. A 4:12 pitch shows up on agricultural and architectural metal buildings. Low-slope roofs still need positive drainage — converting to percent helps check that gutters and crickets meet the 1–2% intent on civil drawings.
FAQ
Is pitch always over 12?
U.S. architectural pitch is rise per 12 inches of run. Some shops say “1/4 on 12,” which is 0.25 in the pitch field here.
Does percent grade equal pitch × 100 / 12?
Yes for small slopes: percent = (rise/run) × 100 = (pitch/12) × 100. Degrees use arctangent of that ratio.
Can I use this for stairs or ramps?
Yes for geometric conversion. Code compliance (IBC ramp slopes, stair angles) still needs the applicable building code limits.
Why so many decimals on pitch from degrees?
Trig conversion is exact; detailing often rounds pitch to 1/8 or 1/4 on 12. Round to match your drawing standard after converting.