108 in total rise
- Actual riser
- 7.7142857143 in
- Treads
- 13
- Total run
- 130 in
- Angle
- 37.6476206401 deg
Stair rules are safety critical and local. Check code, landings, headroom, handrails, and uniformity before building.
Stair Calculator
Use this free stair calculator to estimate riser count, actual riser height, tread count, total run, and stair angle for a simple stair layout.
Inputs explained Result checks Example values Runs in your browser
Formula steps
- Divide total rise by the target riser height and round to a whole riser count.
- Divide total rise by that riser count to get the actual riser height.
- Use one fewer tread than risers for a typical straight stair run.
How to use the Stair Calculator
- Enter total rise, target riser height, and tread depth in inches.
- Press Calculate stair layout to see risers, treads, run, and angle.
- Use the result for rough layout conversation only.
- Check local code for uniformity, handrails, headroom, landings, and finished surfaces.
What people use it for
Estimate a simple straight stair layout.
Find actual riser height after rounding to a whole step count.
Estimate total horizontal run.
Check the stair angle for planning conversation.
Quick examples
Basement rise
108 in rise, 7.5 in target riser, 10 in tread14 risers
Deck rise
36 in rise, 7 in target riser, 11 in treadSimple stair estimate
Tall rise
144 in rise, 7.75 in target riser, 10.5 in treadRiser and run estimate
Need the guide or a nearby tool?
Need a slower walkthrough, a related calculator, or the full library? These links keep you close to the task you started.
- How to use the Stair Calculator See slower examples, input meanings, formula notes, result limits, and mistakes to avoid.
- Calculators Browse related calculators and utilities in the same category.
- Calculator and utility guides Find more guides that use real tool inputs and example numbers.
- All free tools Search every live tool, converter, calculator, AI helper, and browser utility.
Frequently asked questions
Plain-language answers about when to use the tool, what it does with your inputs, what to double-check, and how privacy works.
When should I use the Stair Calculator?
Use it when your task matches one of these common needs: Estimate a simple straight stair layout. Find actual riser height after rounding to a whole step count. It works best when you already know the measurements, amounts, units, or options the page asks for.
What is the Stair Calculator doing with my inputs?
In plain language: The calculator divides total rise by target riser height, rounds to a whole riser count, then calculates actual riser height and run from tread depth. The examples on the page are there so you can compare your inputs with a worked example before copying the answer.
What do the main Stair Calculator inputs mean?
Total rise: the vertical distance from the lower finished floor to the upper finished floor. Target riser: the step height you are aiming for before the calculator rounds to a whole number of risers. Tread depth: the horizontal walking depth of each tread used to estimate total run and angle.
How should I read the Stair Calculator answer?
Read the headline answer, then check the supporting lines and examples to understand how the calculator got there. If one input changes, rerun the tool and compare the new answer instead of guessing.
What should I double-check before trusting the answer?
Stairs are safety critical. Check local building code, uniformity, headroom, landings, handrails, and professional requirements before building. Also check the unit, scale, mode, and result limit because small input changes can change the answer.
Why can stair math not replace building code?
Stairs affect safety every time someone uses them. Code rules can cover riser limits, tread depth, uniformity, landings, headroom, handrails, guardrails, and local inspection requirements.
Does the site save what I enter?
No. The calculator runs in your browser tab. Your recent answers stay only on the page while you use it, and they are not sent to a server.