Key takeaways
- Every riser should be the same height to within about three-eighths of an inch.
- The International Residential Code generally allows a maximum riser of about seven and three-quarter inches and a minimum tread of ten inches.
- Headroom of about six feet eight inches is generally required.
Rise and run
Rise is the height of one step and run is the depth of the tread. The total rise is the height from finished floor to finished floor, and dividing it by a comfortable riser height tells you how many steps you need. Then the total run is the number of treads multiplied by the tread depth.
A comfortable stair often has a riser around seven inches and a tread around eleven, but the space may decide.
Code basics
The International Residential Code, adopted with local changes, generally sets a maximum riser of seven and three-quarter inches, a minimum tread of ten inches, headroom of about six feet eight inches and handrails on stairs of several risers. Guards are typically needed at open sides where there is a drop.
Local codes vary, so we confirm the rules at your address and the permit office decides.
Planning and building
Stairs need space. A set of stairs for a nine-foot rise needs around twelve or thirteen treads and a long run, so many plans include a landing or a turn. We lay out the stringers, cut them precisely and check each step before the treads go on.
Our Stair Calculator gives you a first look at riser height, tread depth, run and code checks.
Related services
Quick answers
Why do stairs feel awkward when risers differ?
People learn the rhythm of a stair in a few steps, and a riser that is even a half inch different can trip them. Good stairs keep every riser within a tiny tolerance.
Do deck stairs need handrails?
Codes generally require handrails on stairs with several risers, and guards where the drop is tall. Rules vary by place.
Ready to talk it through? Get a free estimate or call 615-431-3789.