Stair Calculator
Calculate stair rise, run, number of steps, and stringer length from total rise and desired step dimensions.
Stair Dimensions
Vertical height from bottom floor to top landing.
Typical range: 6–8 in (15–20 cm).
Typical minimum: 10 in (25.4 cm). 11–12 in is comfortable.
Results
Enter dimensions and press Calculate
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Number of Steps
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Actual Rise / Step
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Run / Step
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Total Run
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Stringer Length
Stair Diagram
Diagram updates after you calculate.
Summary
Calculate stair rise, run, number of steps, and stringer length from total rise and desired step dimensions.
How it works
- Enter the total rise — the vertical height from floor to floor (or top of landing).
- Enter your desired riser height (typically 6–8 inches or 15–20 cm).
- Enter your desired tread depth (run), typically 10–12 inches or 25–30 cm.
- The calculator finds the ideal number of steps and adjusts the actual rise to fit evenly.
- Results include individual rise, run, stringer length, total run, and a step-by-step summary.
Use cases
- Planning deck stairs for a backyard project.
- Designing interior staircases to meet building code requirements.
- Estimating stringer lumber length before purchasing materials.
- Verifying rise-to-run ratios comply with residential code (7-11 rule).
- Calculating outdoor concrete steps from a porch to grade.
- Double-checking stair geometry before pouring footings.
Frequently Asked Questions
Last updated: 2026-05-23 ·
Reviewed by Nham Vu