Staircase Calculator

About this calculator

Given the total rise (floor-to-floor height) and either a target step count or a preferred riser height, this calculator works out the actual number of steps and the real riser height per step, since the total rise rarely divides evenly and building codes typically require every riser in a staircase to be the same height for safety.

DIY builders, carpenters, and contractors use it when framing a new staircase or replacing one, and it's also used to check whether a planned staircase meets typical code guidelines for comfortable, safe riser height (commonly in the 15–20 cm / 6–8 inch range) and tread depth. The calculator also derives the stringer angle and total run, which are needed to cut the stringers (the diagonal support boards) to the correct length.