🪜 Stair Stringer Calculator

Size a straight staircase: enter the total rise and your preferred riser height, and get the number of steps, the tread depth, total run and the stair angle — checked against the comfortable 2×rise + going rule.

Comfort & the rule of thumb

A comfortable stair keeps risers between about 6½" and 7¾" and satisfies 2 × riser + tread ≈ 24–25" (ideally 25"). Number of treads is always one fewer than the number of risers. Always confirm against local building regulations — the UK requires a maximum pitch of 42° and a minimum going of 220 mm for domestic stairs.