Staircase calculator
Steps, riser height, flight length and whether you need a dog-leg — checked against dwelling comfort norms and the 2R + T stride rule. Give it your available straight run and it tells you if the flight fits.
- Riser 167 mm — Keep a dwelling riser at or under 190 mm — taller steps are what make a staircase feel like a ladder.
- Tread 250 mm — 250 mm is the minimum that takes an adult foot; 280–300 mm is comfortable.
- 2 × riser + tread = 583 mm — The stride rule: 550–700 mm walks naturally.
- Flight width 900 mm — Under 900 mm and a mattress or a fridge will not go up.
The staircase inside a real plan
In a Plot2Plan floor plan the staircase is a room the validator takes seriously: it must sit at the same position on every floor, join the floors for circulation, and its mumty on the terrace is height-exempt. This page sizes the flight itself; the plan decides where it goes.
Common questions
How many steps for a 10 ft (3 m) floor height?
Aiming at a 175 mm riser, 3 m of height needs 18 steps of about 167 mm each — split as a dog-leg of two flights of 9 with a mid-landing, since more than about 12 steps in one straight run tires people and most stair wells cannot take the 4.25 m straight-flight length anyway.
What is a comfortable riser and tread size?
For homes: riser 150–190 mm (under 175 feels gentle), tread at least 250 mm with 280–300 comfortable. The classic stride check is 2 × riser + tread = 550–700 mm — inside that band a flight walks naturally; outside it people stumble or shuffle.
How long does a staircase run?
Horizontal run = treads × tread depth, and treads are one fewer than risers. 18 risers with 250 mm treads run 4.25 m as a straight flight — or about 2.25 m per flight as a dog-leg, plus the landing. Give the calculator your available run and it checks the fit.
How wide should a house staircase be?
900 mm is the sensible minimum — narrower and furniture, mattresses and stretchers do not go up. 1,000–1,100 mm feels generous in a duplex. Keep headroom at least 2.1 m at every point of the climb.