About FramersMath

FramersMath started as a single-page calculator built for a home addition: rafters, stairs and stud layout, in the feet-inch-fraction format you actually read off a tape. It turned out to be useful enough to share.

The goal is simple: fast, free framing calculators that work on a phone on the jobsite. No accounts, no app to install, and no clutter around the numbers.

How the math is checked

Every calculator runs on the same small, shared math library. Before each update, an automated test suite checks it against known-good values, including the common rafter, hip/valley and jack-difference tables stamped on a steel framing square, standard stair layouts, and feet-inch-fraction rounding at 1/8", 1/16" and 1/32".

Use it as a tool, not a stamp

These are layout calculators. They don't replace engineered plans, span tables or your local building department. Always verify measurements and check local code before cutting. See the terms & disclaimer.

Suggestions

Found a bug, or want a calculator that isn't here yet (deck joists, concrete, sheathing, drywall)? Get in touch.