Stair Calculator
Enter one number — the total floor-to-floor rise — and get the whole stair: an exact, uniform riser height (the thing hand charts botch), tread count, total run, stringer length and count, and the incline angle. Accepts tape-measure input like 8' 7-3/8" and answers the same way.
Planning tool — results are estimates for quoting and ordering, not engineering or building-code advice.
Common questions
How does it choose the number of risers?
It divides your total rise by a comfortable target riser height (default 7"), rounds to the nearest whole count, then nudges the count so the resulting riser lands in the comfortable 4-3/4"–8" band. Every riser comes out exactly equal.
What do the comfort hints mean?
They check the classic comfort rules: riser height band, 2×riser + run between 24" and 25", and an incline between 30° and 37°. They're guidance for a walkable stair, not building-code advice — always verify against your local code.
Can I type feet and inches?
Yes — type it the way you'd say it: 8' 7-3/8", 103.375, even 6½. The calculator reads feet-inch-fractions and plain decimals.
Related: Stairkey for general contracting · Free estimate template
More free calculators
All 14 are free, feet-and-inches in, no sign-up. Pick the next one for the job.
Stairs & framing
Concrete & site work
Finishes & materials
This solves one measurement. The Takeoff Builder prices the whole job.
Walk the rooms, enter dimensions, and formula-driven scope turns measurements into quantities, prices, and the estimate itself — from $20/mo, capped, no surprise bills.