About Stair & Stringer Calculator
Balance a measured total rise across equal risers and derive the matching stair run.
Inputs and calculations stay in your browser and require no signup.
How the calculation works
Planning calculation
Risers round up from total rise ÷ maximum riser; treads are one fewer; the stringer is the right-triangle hypotenuse.
How to use this calculator
- 1Enter measured project dimensions and quantities.
- 2Adjust material, spacing, waste or density assumptions to match the project.
- 3Review the live planning quantities.
- 4Round purchasing quantities appropriately and confirm field conditions.
Understanding the result
Actual riser height is recalculated so every riser is equal after choosing a whole riser count.
Results use the units shown beside each field and output.
Important limitations
- Planning only; no universal code-compliance claim is made.
- Verify local limits, headroom, landings, nosing, guards, handrails and stringer strength.
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Frequently asked questions
Why are there fewer treads than risers?
A typical stair flight ends at the upper floor, leaving one fewer horizontal tread.
Are all risers equal?
The tool divides total rise evenly across the calculated whole number of risers.
Does it guarantee code compliance?
No. Requirements vary by jurisdiction and configuration.
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