Lay out code-friendly stairs: enter your total rise to get the number of risers, exact riser height, tread count, total run, and stringer length. Keeps every step even — the thing inspectors check first.
How to use this calculator
- Measure the total rise — finished floor to finished floor (or ground to deck surface) in inches.
- Set your target riser height (7.5 in is comfortable; most codes max at 7¾ in).
- Set tread depth — 11 inches is standard and code-friendly.
The math behind it
Risers = total rise ÷ target riser height, rounded up — then actual riser height = total rise ÷ risers, so every step is identical. Treads = risers − 1. Total run = treads × tread depth. Stringer length = √(rise² + run²).
FAQs
What is the standard riser height?
Most US residential codes allow a maximum riser of 7¾ inches and require a minimum tread depth of 10 inches. Comfortable stairs land around 7–7.5 in risers with 11 in treads.
Why do my risers need to be even?
Uneven risers are a trip hazard and a code violation — codes typically limit variation to ⅜ inch between the tallest and shortest riser in a flight. This calculator divides the rise evenly by design.