One riser even a half-inch taller or shorter than the rest is a documented cause of trips on stairs — people's feet learn the rhythm of a staircase after the first two or three steps and stop consciously checking each one.
Stair rise and run calculator, with uniform steps
Enter the total floor-to-floor rise, and this calculator finds the number of steps that divides that height evenly — so every riser comes out exactly the same height, rounded to a step count near the comfortable 7.5" target rather than picking an arbitrary riser height first.
How many stairs do I need
The step count is a direct output, not something you have to back into by trial and error — along with the resulting riser height, the total horizontal run the staircase will take up, and the stair's angle in degrees.
Stair riser height calculator, checked against code
The result is checked against the US IRC's typical residential limits — a maximum 7¾" riser and a minimum 10" tread — with a clear pass/fail note, since a comfortable-looking staircase on paper can still fail inspection.
