Construction
Stair Calculator
Enter your total floor-to-floor rise. We calculate equal-spaced risers and treads, plus stringer length — and warn you if it falls outside residential code.
Enter total rise to begin.
IRC residential code limits
- Max riser: 7.75"
- Min tread depth: 10"
- Variation between risers (or treads): no more than 3/8"
- Most jurisdictions follow IRC; check your local code anyway.
FAQ
Why is one tread typically not included in the run count? +
The top tread is the landing/floor above. So if you have 14 risers, you have 13 treads.
What's a comfortable rise/run combination? +
2 × riser + tread ≈ 25"–26" feels natural. So a 7" riser pairs well with an 11"-12" tread.