Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Riser height
7.714
Number of risers
14
Number of treads
13
Total run (in)
136.5
Stringer length (ft)
14.50
Stair angle (degrees)
36.3
Code check
Meets typical code
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter total rise (floor to floor) (in).
- 2Enter target riser height (in).
- 3Enter tread depth (in).
- 4Read your riser height on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
Most residential codes cap risers at 7.75 inches and require treads of at least 10 inches. This divides your total rise into equal risers and checks the result against those limits.
Worked example
Using the values the calculator loads with:
Inputs
- Total rise (floor to floor): 108 in
- Target riser height: 7.5 in
- Tread depth: 10.5 in
Results
- Riser height: 7.714
- Number of risers: 14
- Number of treads: 13
- Total run (in): 136.5
- Stringer length (ft): 14.5
- Stair angle (degrees): 36.3
- Code check: Meets typical code
What each field means
Inputs
- Total rise (floor to floor) (in)
- The total rise (floor to floor) used in the calculation, measured in in. Starts at 108 in so you have a working example on load.
- Target riser height (in)
- The target riser height used in the calculation, measured in in. Starts at 7.5 in so you have a working example on load. Accepted range: 4–8.25 in.
- Tread depth (in)
- The tread depth used in the calculation, measured in in. Starts at 10.5 in so you have a working example on load. Accepted range: 9–14 in.
Results
- Riser height
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Number of risers
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Number of treads
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total run (in)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Stringer length (ft)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Stair angle (degrees)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Code check
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the stair calculator work?
Most residential codes cap risers at 7.75 inches and require treads of at least 10 inches. This divides your total rise into equal risers and checks the result against those limits. The underlying maths is: Risers = round(Total rise ÷ Target riser). Riser height = Total rise ÷ Risers. Run = Treads × Tread depth.
What do I need to enter?
3 values: total rise (floor to floor), target riser height, and tread depth. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the riser height result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Stair Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/stair
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/stair" target="_blank" rel="noopener">Stair Calculator — RevenueLab</a> (2026).</p>
Source: [Stair Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/stair) (2026).