Calculators / Home and DIY

Stair calculator

Enter the floor-to-floor height. The calculator picks the fewest steps that keep each riser at or below your maximum, then sizes the treads with the step rule.

cm
cm
cm
Risers (steps)15
Riser height18.0cm
Tread depth27.0cm
Total run (treads = risers − 1)378cm

How it is calculated

Risers = height ÷ maximum riser, rounded up. Riser = height ÷ risers. Tread = step length − 2 × riser (Blondel step rule, 60–65 cm). Local building rules set the legal limits; check them before you build.

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