Staircase calculator
Give it the floor-to-floor height and it works out the risers, the tread and the going — then checks them against the comfort rule and the NBC minimums.
Finished floor to finished floor — not ceiling height.
How the numbers are worked out
A staircase is fixed by one number you cannot change — the floor-to-floor height — and one you choose: how steep it is allowed to be. Everything else follows.
1. The number of risers
Risers must be equal, so the count is the height divided by the tallest riser you will accept, rounded up. The calculator starts from a comfortable 165 mm and takes the first whole number of risers that keeps the riser within the limit for the building type.
A flight always has one more riser than it has treads: the top riser lands you on the floor above, which is not a tread.
2. The comfort rule
The proportion that makes a stair feel right is old and empirical — two risers plus one tread should land between 550 and 700 mm, ideally near 630. Steep-and-shallow or shallow-and-deep both fail it, and both are unpleasant to use.
3. The regulation minimums
The National Building Code sets floors under all of it. These are the values the checks use:
| Building type | Max riser | Min tread | Min width |
|---|---|---|---|
| House / individual dwelling | 190 mm | 250 mm | 750 mm |
| Apartment block | 190 mm | 250 mm | 1,000 mm |
| Assembly / institutional / business | 150 mm | 300 mm | 1,500 mm |
Two more that the calculator flags but cannot decide for you: headroom must be at least 2,100 mm measured vertically from the nosing line, and a single flight should not run more than about 12 risers without a landing.
Common questions
What is the ideal riser height for a house?
Between 150 and 175 mm. The NBC allows up to 190 for a dwelling, but a stair at the limit is noticeably hard work, particularly going down. If the height divides awkwardly, add a riser rather than push towards 190.
How many steps for a 10-foot floor height?
3,048 mm needs 18 risers of 169 mm, or 19 of 160 mm for an easier climb. With a 250 mm tread, 18 risers give a total going of 4,250 mm — so a straight flight needs a run of about 4.3 m, which is usually why the stair turns.
What is the difference between tread and going?
The going is the horizontal distance from one riser face to the next. The tread is the board you stand on, which is usually the going plus a nosing overhang of 20–25 mm. Codes dimension the going; carpenters talk about the tread. This calculator uses them interchangeably, as most people do — set the going and add your nosing separately.
Must every riser be the same height?
Yes, and it matters more than any other rule here. People climb stairs without looking; a single riser out by even 10 mm is a trip. If the top step is short because of a floor finish, the whole flight has to be reset.
Building in Himachal?
The stair is one line in a sanction drawing. Trace your tatima and get the whole plot worked out — coverage, setbacks, height and parking, against the HP rules.
Trace your tatima → Read the HP rules →