How many steps do I need?

Divide the total floor-to-floor rise by a comfortable riser height (about 7–7.75 inches) and round to the nearest whole number. Enter your rise above for the exact count.

What is a comfortable stair riser height?

Most codes cap risers around 7.75 inches; 7–7.5 inches feels comfortable, with a tread depth of 10–11 inches.

The stringer is the sloped board that supports the treads. Its length is the diagonal from the bottom to the top of the stairs, so you can buy a board long enough.

Stair Calculator

Work out a staircase from the total rise. Enter the floor-to-floor height and a target riser to get the number of steps, the exact riser height, the total run, and the stringer length.

Stair calculator

Total rise is the finished floor-to-floor height. A comfortable riser is about 7–7.75 in and a tread 10–11 in — always check your local building code.

How to use it

Measure the total rise (finished floor to finished floor) in inches.
Set a target riser (7–7.5 in is comfortable) and a tread depth (10–11 in).
Read off the step count, riser height, run, and stringer length.

How it's calculated

We divide the total rise by your target riser and round to whole steps, then compute the exact riser (rise ÷ steps), the run (treads × tread depth, where treads = steps − 1), and the stringer as the diagonal (hypotenuse) of the rise and run.

Frequently asked questions

How many steps do I need?: Divide the total floor-to-floor rise by a comfortable riser height (about 7–7.75 inches) and round to the nearest whole number. Enter your rise above for the exact count.
What is a comfortable stair riser height?: Most codes cap risers around 7.75 inches; 7–7.5 inches feels comfortable, with a tread depth of 10–11 inches.
What is a stringer?: The stringer is the sloped board that supports the treads. Its length is the diagonal from the bottom to the top of the stairs, so you can buy a board long enough.

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<iframe id="hmc-stair-calculator" src="https://howmanycalc.com/embed/stair-calculator/" title="Stair calculator by HowManyCalc" width="100%" height="520" style="border:1px solid #e4e8ec;border-radius:12px;max-width:680px" loading="lazy"></iframe>
<p style="font:12px sans-serif">Stair calculator by <a href="https://howmanycalc.com/stair-calculator/">HowManyCalc</a></p>
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Last updated June 2026.