How this calculation works
Rounding the number of risers up keeps the resulting equal riser height at or below the entered maximum. The number of treads depends on landing and staircase configuration.
Risers = ceiling(total rise ÷ maximum riser); actual height = total rise ÷ risersA worked example
A total rise of 280 cm with a maximum 18 cm riser gives 16 risers, each 17.5 cm.
Good to know
Not a building-code compliance or structural design check. Confirm local riser/tread, landing, headroom and handrail requirements.
Rounding the count up makes individual steps smaller
A 280 cm rise divided by an 18 cm maximum gives about 15.56. Using 15 risers would exceed that chosen maximum, so the tool rounds up to 16. Dividing the total evenly then gives 17.5 cm per riser.
The maximum input is a design constraint you supply, not a statement of the legal limit in your location. The result simply finds a whole count consistent with that entered bound.
A riser count is not a complete staircase
Tread depth, number of treads, landing arrangements, available run, headroom, handrails and uniformity requirements all matter. A staircase joining two levels may use the upper floor as the final walking surface, so tread count is not automatically identical to riser count.
Confirm all relevant local rules and project dimensions before construction. This geometric estimate should support, rather than replace, an appropriate design review.
A few questions, answered
Why is the calculated riser below my maximum?
The count must be a whole number. Rounding it up reduces each equal riser so the entered maximum is not exceeded.
Does it choose a legal stair dimension?
No. You supply the maximum and must verify applicable requirements independently.