Stair Calculator
Calculate stair steps, riser height, tread depth, stringer length and angle with this free online stair calculator, including building code checks.
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How to use Stair Calculator
- 1Choose inches or centimetres
- 2Enter the total rise from floor to floor, your target riser height and the tread depth (or the total run)
- 3Read the number of steps, actual riser height, total run, stringer length, angle and code checks
Frequently asked questions
How many steps do I need for 9 feet?▾
A 108 inch rise with a target riser of 7.5 inches needs 15 risers of 7.2 inches and 14 treads. With 10.5 inch treads the total run is 147 inches.
What is the maximum riser height for stairs?▾
The US International Residential Code allows a maximum riser height of 7.75 inches and a minimum tread depth of 10 inches for residential stairs.
What is the 2R + T rule?▾
Twice the riser height plus the tread depth should be about 24 to 25 inches (61 to 64 cm). Stairs within that range feel natural to walk on.
Embed Stair Calculator on your website▾
Paste this snippet into your page. The embedded tool runs in your visitor's browser and shows a small “Powered by clkr.work” link.