Staircase Dimensions: Standard Step Height and Width for Safe Stairs
🇹🇷 This article describes regulations and processes specific to Turkey — requirements differ in other countries.
How tall should a stair riser be, and how wide should the tread be? The 2h+b formula, landing rules, and practical dimensions for a safe residential staircase.
A staircase leaves the smallest margin for error of any building element. Even a few millimeters of variation between steps can cause someone to trip, because the body memorizes a walking rhythm after the first two steps.
Basic dimensions
| Dimension | Inside a home | Shared staircase |
|---|---|---|
| Riser height (h) | 16–18 cm | 15–17 cm |
| Tread width (b) | 27–30 cm | 28–32 cm |
| Flight width | 90–100 cm | at least 120 cm |
| Headroom clearance | at least 220 cm | |
| Handrail height | 90–110 cm | |
The 2h + b formula
The golden rule for a comfortable staircase:
(2 × riser height) + tread width = 60–64 cm
Example: with a 17 cm riser and a 29 cm tread, (2×17)+29 = 63 cm — right in the middle of the range.
A staircase below this range feels "rushed"; above it, it feels "tiring."
Calculating the number of steps
For a home with a 285 cm floor-to-floor height:
- 285 ÷ 17 = 16.7 = 17 risers
- 285 ÷ 17 = 16.76 cm actual riser height
- Number of treads = number of risers − 1 = 16 treads
If the division doesn't come out even, don't dump the remainder onto the last step — spread the difference across all the risers equally. An uneven final step is the single most common cause of accidents.
If you'd like to try this calculation live for your own floor-to-floor height and preferred riser size, you can use our Staircase Step Calculator.
Landings and turns
- No more than 16–17 steps in an unbroken flight; add a landing after that.
- The landing's depth should be at least equal to the flight's width.
- On winder (pie-shaped) steps, the tread width measured 40 cm in from the narrow end must be at least 10 cm, and match a normal tread width along the walking line.
Common mistakes
- Not accounting for finish thickness — working off the raw screed measurement and throwing off the risers once the final flooring goes in.
- Letting the headroom clearance collide with the floor slab above.
- Leaving the handrail as an afterthought once the staircase is already built.
