Free stair calculator
Calculate stair rise, tread run, total run and angle from a finished-floor rise. This web demo uses the same StructCalc core stair logic as the Android app, so the numbers match the mobile workflow.
Need this on site?
Get the full StructCalc Android app for offline stair, rafter, square check and jobsite layout calculators.
Free on Google Play Download StructCalcStart with the finished-floor to finished-floor rise. StructCalc divides that rise by its target stair rise, then returns three nearby layout options: fewer steps, the ideal layout and more steps. Each option gives tread rise, tread run, stair angle and total run.
The standard mount option treats the top floor as the final step. Flush mount includes the extra run because the top tread lands flush with the upper level. That distinction matters when you are checking available floor space or marking a stair opening.
For a total rise of 2800 mm, the calculator returns a set of practical stair layout options. You can compare the total run and angle before committing to a stringer layout. On site, that makes it easier to check whether the stair fits the available opening and whether the rise and run feel reasonable.
StructCalc for Android includes stair, rafter, baluster, raked wall, square check and measurement tools with a faster jobsite workflow. Use the web demo for a quick number, then use the mobile app when you need the full calculator set offline.
Get StructCalc on Google Play