Stair Calculator
Enter the total rise to get the number of steps, exact riser height, tread count, and total run — flagged against common code limits.
Stair run
Measure the total vertical height between finished floors. Common residential code: riser ≤ 7-3/4", tread ≥ 10".
Your stairs
Within common residential limits — always confirm local code.
How to lay out stairs
Divide the total rise by a target riser (~7.5") and round to whole risers, then divide the total rise by that count for the exact riser height. Treads equal risers minus one; total run is treads × tread depth. Keep risers ≤ 7-3/4" and treads ≥ 10".
Capture floor-to-floor heights from a scan
ProBuildCalc turns your iPhone's LiDAR scanner into a job-site measuring kit — walk the space and it captures the square footage, material takeoff, and a blueprint automatically. No tape measure, no graph paper.
Stair calculator FAQ
- How many steps do I need?
- Divide the total floor-to-floor rise by a comfortable riser height of about 7 to 7.5 inches and round to the nearest whole number. A 108-inch rise divided by 7.5 is about 14 risers.
- What is the maximum riser height?
- The widely adopted residential limit is a maximum riser of 7-3/4 inches and a minimum tread depth of 10 inches, with no more than 3/8 inch variation between steps. Always confirm your local code.
- What's the difference between rise and run?
- Rise is the vertical height of each step (and the total rise is floor to floor); run is the horizontal tread depth. Total run is the tread depth times the number of treads, which is the number of steps minus one.
- How do I find the riser height exactly?
- Once you fix the number of risers, divide the total rise by that number. Fourteen risers over a 108-inch rise gives 7.71 inches per riser — every riser should be equal.