Pitch Converter
Convert roof pitch between x/12, degrees, and slope percent instantly.
Estimates only — verify with local code and the product label.
How this works
Roof pitch is a slope, and any slope can be written three common ways: as x/12 (the roofing-industry standard — a roof rises x inches for every 12 inches it runs horizontally), as an angle in degrees, or as a percent grade. All three describe the exact same slope, so converting between them is plain trigonometry with no rounding assumptions or waste factors involved, unlike most of the other calculators here.
The math: for an x/12 pitch, the angle in degrees is atan(x / 12) converted from radians, and the percent grade is (x / 12) × 100. Going the other direction works the same way in reverse — from an angle, rise = tan(angle) × 12; from a percent grade, rise = (percent / 100) × 12.
This matters on a job site more often than it seems: pitch gauges read in x/12, some laser tools and specs read in degrees, and grading/drainage numbers are usually given in percent. Being able to move between them quickly avoids re-deriving the trig by hand or guessing. It's also useful context for the roofing and gutter tools on this site, both of which ask for a pitch or slope input in a specific format.
Frequently asked
What's a 'normal' roof pitch?
Most residential roofs in Minnesota run 4/12 to 8/12. Lower than 4/12 needs different underlayment and flashing details; steeper than 8/12 gets harder and slower to walk safely.
Is 45 degrees the same as a 12/12 pitch?
Yes exactly — a 12/12 pitch rises 12" for every 12" of run, a 1:1 slope, which is a 45° angle and a 100% grade.
Questions about a project? Contact us.