Stair Calculator
Calculate stair riser count, actual rise, total run, stringer length, tread boards, fasteners and material cost.
Default project preview
13 risers
Actual riser height
7.38 in
Treads
12
Required run
126 in
Stringers
4
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Risers = round up (total rise ÷ target riser). Actual rise = total rise ÷ risers. Treads = risers − 1. Required run = treads × tread depth. Stringer length = √(rise² + run²).
FAQ
Stair Calculator questions
Why must every riser be equal?+
Unequal risers create a serious trip hazard and are restricted by building codes. Final construction measurements must be precise.
Does this approve a stair for code compliance?+
No. It is a planning calculator. Local rules govern geometry, landings, guards, handrails, headroom and structure.
Why can required run exceed available run?+
The chosen tread depth multiplied by the number of treads may need more horizontal space than entered. The design must then change.