About the Stair Calculator
Enter the total floor-to-floor rise and a target riser height to get the number of steps, the exact (equal) riser height, and the total horizontal run. Includes a comfort check against the standard stair rule.
How it’s calculated
Steps = round(total rise ÷ target riser). Actual riser = total rise ÷ steps. Total run = (steps − 1) × tread depth.
Example calculation
A 108 in total rise with a 7.5 in target riser gives 14 steps at about 7.71 in each.
Frequently asked questions
What riser height is comfortable?
Around 7–7.75 inches, kept equal across all steps. The '2 × riser + tread ≈ 24–25 in' rule is a comfort guideline. Building codes set legal limits — always check yours.
Why must risers be equal?
Uneven risers are a trip hazard and usually violate code. Dividing the total rise into equal steps is the whole point of the calculation.
This is a general material estimate for planning only. Actual quantities vary with waste, offcuts, site conditions, product coverage, and technique. Confirm measurements and coverage rates before ordering, follow local building codes, and round up — running short mid-project is costly.