Rise, going and pitch of a stair, checked against the rules STAIR
The number of risers is the only real choice, and each choice fixes the rise. Every one that fits is listed, with the going it allows. How many stairs for a 9-foot ceiling.
The stair
The rise is finished floor to finished floor, with the floor coverings in. The going is measured nosing to nosing, on plan. There is one tread fewer than there are risers, because the top step is the landing.
Every number of risers that fits
The working
The limits are the published figures: Approved Document K (2013) table 1.1 for England, with 2R + G between 550 and 700 mm as its normal relationship and 42° as the steepest private stair; IRC R311.7.5 and IBC 1011.5.2 for the United States. Headroom (2.0 m in England, 6 ft 8 in under the IRC), handrails, guarding, landings and tapered or winding treads are not checked here, and building control is the authority.
How it works
STAIR works out a straight flight from the floor-to-floor height: every whole number of risers whose height is inside the limits, the going each allows, the pitch, the total run and 2R + G. It checks against Approved Document K for England and the IRC and IBC for the United States, and says what it does not check. The measurements stay in this tab.
Doing this often? Foundry, the Engineering Suite's drawing half draws the stair to scale, with dimensions, and prints a PDF to scale or saves DXF. On its own, US$2 a month; with everything else, US$5 a month or US$48 a year. 7 days free.