Calculator guide
Size equal stair risers and treads from total floor-to-floor rise. Use the explicitly labelled inputs below; rates, dimensions, and costs are assumptions, not live quotes.
Formula or method
Riser count = ceiling(total rise ÷ target riser height). Actual riser height = total rise ÷ riser count. Tread count is one fewer than riser count.
How to use this calculator
- Set Total rise (in). The interface starts with 108; replace it with the value for your scenario.
- Set Target riser height (in). The interface starts with 7.5; replace it with the value for your scenario.
- Set Tread depth (in). The interface starts with 10; replace it with the value for your scenario.
- Compare the result with the worked example, then vary one assumption at a time so you can see what changes.
Worked example
Enter Total rise = 108 in; Target riser height = 7.5 in; Tread depth = 10 in. With those assumptions, the calculator gives Risers: 15; Actual riser height: 7.2 in; Treads: 14; Total stair run: 11.67 ft. These outputs are calculated from the same implementation as the interactive tool.
Understanding the result
In this example, Risers is 15. Actual riser height is 7.2 in. Verify measurements, manufacturer coverage, packaging, local code, and site conditions. Quantity and budget estimates do not certify structural or electrical safety.
Limitations and assumptions
- Verify measurements, manufacturer coverage, packaging, local code, and site conditions. Quantity and budget estimates do not certify structural or electrical safety.
- The worked example demonstrates the stated assumptions, not a recommendation about your personal circumstances.
Frequently asked questions
Which inputs should I check first?
For Stair Calculator, check Total rise, Target riser height, Tread depth. Keep the displayed units and select options consistent; do not treat default values as recommendations.
Why might my result differ from another tool?
Compare the other tool's stair calculator method, input units, rounding and assumptions. A matching title does not guarantee that both tools answer the same question.
Does a linked reference certify this result?
No. A reference can explain a formula or provide background for Stair Calculator, but it does not endorse this website, validate personal inputs or establish professional suitability.
Sources
Educational and planning information only. Sources are attributed background or formula references, not endorsements. Verify consequential decisions with an appropriate qualified professional.