Risers--
Actual riser height--
Total run--
Stair Stringer Calculator
Estimate stair rise, run, number of risers, tread count, and total horizontal run. Use it as a layout check before cutting stringers.
Updated May 2026No signup requiredBuilt for mobile
How to use this calculator
Enter the real measurements or counts you have now, run the calculator, then round the result in the practical direction before buying supplies or making a plan.
Formula or calculation method
Risers = round(total rise / desired riser height)
Actual riser height = total rise / risers
Tread count = risers - 1
Total run = tread count x tread depth + landing
Practical examples
Example 1
A 48 inch rise with a 7 inch target riser rounds to 7 risers at about 6.86 inches each.
Example 2
With 6 treads at 10 inches each, the stair run is about 60 inches before any landing.
Useful assumptions
- This calculator gives a planning layout, not code approval.
- Check local building rules for riser height, tread depth, handrails, and landings.
- Measure total rise from finished surface to finished surface.
Common mistakes
- Cutting before checking local stair rules
- Forgetting that tread count is usually one less than riser count
- Using uneven riser heights
- Ignoring landing and nosing details
FAQ
Stair Stringer Calculator questions
How many stringers do stairs need?
That depends on stair width, tread material, and code requirements. Many residential stairs use multiple stringers spaced evenly.
What is total rise?
Total rise is the vertical distance from the lower finished surface to the upper finished surface.
Why is tread count different from riser count?
Most stairs have one fewer tread than risers because the top floor or deck acts as the final landing.
Can I use this for code approval?
No. Use it for planning, then verify local requirements before building.
Should all risers be equal?
Yes. Uneven risers are a common trip hazard.