About RiseRun
A small, focused tool that does one job: the arithmetic behind a stair layout.
Built for the measure-twice moment
RiseRun started as a scratch calculation for a set of basement stairs where the numbers refused to divide evenly. It's meant for that moment before you cut a stringer — checking that a riser count actually fits the rise you've got, and seeing the resulting pitch before it's committed to lumber.
It doesn't store your project, send it anywhere, or track what you calculate. Everything runs in your browser, so you can use it offline once the pages have loaded.
Open the calculator