Roof pitch calculator and chart

A 6:12 roof pitch is 26.6 degrees, a 50.0 percent slope, and a pitch multiplier of 1.1180. The chart below converts every pitch from 1:12 to 24:12 the same way, so you can read the angle and the multiplier without doing the trigonometry.

This chart uses the roofing rise-to-run convention. A 4:12 slope rises 4 inches for every 12 inches of horizontal run; it is the same ratio often written 4/12. The colon form matches the app's X:12 display. In stricter framing terminology, pitch can refer to rise over the full span, so confirm which convention a specification uses.

Roof pitch calculator

Enter the rise and the run and this works out the pitch, the angle in degrees, the percent slope, the pitch multiplier, and the rafter length for that run. Any units work as long as both boxes use the same ones, because every result comes from the ratio.

Roof pitch to degrees conversion chart

How to convert roof pitch to degrees

Take the arctangent of rise divided by run. For a 4:12 pitch that is arctan(4 / 12), which is 18.4 degrees. The run is always 12, so only the rise changes.

Two useful anchors: a 12:12 roof is 45 degrees because it rises as much as it runs, and a 6:12 roof is 26.6 degrees. Neither is a substitute for measuring the roof you are working on.

What the pitch multiplier is for

The pitch multiplier, also called the roof pitch factor or slope factor, converts the horizontal projected area of a roof plane into sloped surface area. Include overhangs in that projected area, and calculate each different pitch separately.

A roof plane with 2,000 square feet of horizontal projected area at 6:12 has about 2,236 square feet of sloped surface: 2,000 multiplied by 1.1180. At 12:12 it has about 2,828 square feet. Add waste and other material allowances separately.

Reading pitch off a roof instead of a chart

A chart converts a known rise and run; it does not measure the roof. For field reference, Pitch Please Direct Mode reads device inclination with the phone resting along a safely accessible slope. Camera Mode saves a roof photo with a fixed guide and the phone's sensor reading; it does not calculate roof geometry from the image.

Choose Imperial X:12 pitch with degrees or International percent slope with degrees in Settings. The app displays the selected system, one at a time. Pitch Please includes built-in calibration and keeps captures in an on-device Saved Pictures archive. Measurement and saved-picture work runs offline without an account. Verify consequential measurements independently.

See how the Pitch Please roof pitch app works, or read the detail on Camera Mode documentation and alignment limits.

Frequently asked questions

What is a 6:12 roof pitch in degrees?

A 6:12 roof pitch is 26.6 degrees. It rises 6 inches for every 12 inches of horizontal run, which is a 50.0 percent slope, and its pitch multiplier is 1.1180.

What is a roof pitch multiplier?

The pitch multiplier converts horizontal projected roof-plane area into sloped surface area. At 6:12, 2,000 square feet times 1.1180 is about 2,236 square feet. Include overhangs, calculate different pitches separately, and add waste and other allowances separately.

How do I convert roof pitch to degrees?

Take the arctangent of the rise divided by the run. For a 4:12 pitch that is arctan(4/12), which is 18.4 degrees. The chart on this page lists every pitch from 1:12 to 24:12 already converted.

What counts as a steep-slope roof?

On this site, "steep pitch" describes slopes above 8:12. Exactly 8:12 is outside that description. This is a description for homeowners and roofers, not a material, code, or fall-protection threshold. Follow the applicable manufacturer instructions, building code, and safety requirements. A 12:12 roof is 45 degrees; pitches above 12:12 rise more than they run.

Can I measure roof pitch with my phone instead of reading a chart?

Pitch Please Direct Mode reads device inclination through contact with a safely accessible slope. Camera Mode keeps a fixed guide and device reading with a roof photo; it does not calculate roof geometry from the image. Choose X:12 with degrees or percent slope with degrees. Check calibration and verify consequential measurements independently.