Stair Stringer Calculator
Rise, run and stringer length for stairs.
Enter your values
ⓘ Live results
Results
- Number of steps
- 14
- Actual riser height
- 7.71 in
- Actual tread depth
- 9.43 in
- Stringer length
- 14.21 ft (170.6 in)
- Stair angle
- 39.3°
Quick answer
The calculator divides total rise by a target riser height to find the number of steps, then sizes the stringer.
steps = round(total rise / target riser); stringer length = sqrt(rise^2 + run^2)
How to use the Stair Stringer Calculator
- 1Measure the total rise from finished floor to finished floor.
- 2Measure or plan the total horizontal run available.
- 3Set a target riser height (code max is usually 7.75 in) and get exact steps and stringer length.
Worked example
Using the values the calculator loads with:
Inputs
- Total rise108 in
- Total run132 in
- Target riser height7.5 in
Results
- Number of steps14
- Actual riser height7.71 in
- Actual tread depth9.43 in
- Stringer length14.21 ft (170.6 in)
- Stair angle39.3°
Frequently asked questions
What riser height is code?
Most residential codes cap risers at 7.75 in with a minimum tread of 10 in, but always check local code.
Why round the number of steps?
You need a whole number of equal steps; the calculator adjusts riser height slightly to keep them even.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.