Staircase Dimensions: Standard Step Height and Width for Safe Stairs

The information in this article applies to Turkey. 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

The regulation column comes from Turkey’s Planned Areas Zoning Regulation, Article 31^[1]. Even if a TSE standard gives a smaller value, Article 31 prevails (Article 31/1-c). The “our recommendation” column is our own view.

An earlier version of this article gave 16–18 cm for the riser inside a home and 90–100 cm for the flight width. We re-read the regulation and corrected it.

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 17 cm riser, however, only meets the regulation in a building with an elevator; without one the limit is 16 cm.

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

This 16.76 cm riser is fine in a building with an elevator. Without an elevator, the 16 cm limit requires 18 risers: 285 ÷ 18 = 15.83 cm.

If the division isn't even, don't leave the difference to the last step; spread it equally across all risers. A single step of a different height breaks the rhythm the walk has settled into.

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

• Article 31 sets no limit on steps per flight; our recommendation is at most 16–17 steps in one uninterrupted flight, then a landing.
• A landing is subject to the same minimum width as the flight (Article 31/1-a); we recommend its depth be at least the flight's width too.
• On winder steps the tread must be at least 10 cm at the narrowest edge and at least 27 cm at the middle of the step (Article 31/2-c).

Shared stairs and the stairwell

Besides the step dimensions, Article 31 also sets these requirements for where the stair sits in the building^[1]:

• Shared stairs that reach the roof or basement levels, and service stairs, follow the same dimensions and may not be made of timber (Art. 31/1-a).
• The stairwell must receive daylight directly from the facade, the roof or a light well, and the stairs must reach the roof and the basements (Art. 31/1-b).
• The space under a stair where the headroom is below 1.80 m must be closed off (Art. 31/6).
• In mixed-use buildings a separate stairwell is required for each use (Art. 31/5).
• Internal stairs to the attic rooms connected to a top-floor unit are exempt from the riser, tread and width conditions (Art. 31/3).
• When floors are added to a building built under the earlier regulations, the existing stair dimensions may be kept for the added floors (Art. 31/4).

The escape width required for fire safety is calculated separately under the Regulation on Fire Protection of Buildings; Article 31 sets 1.20 m as the lower limit, provided it is not less than that calculated width.

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.

Related dimensions

The stair decision usually depends on other decisions: the riser limit changes with whether the building has a lift (when a lift is required in an apartment building), and the floor height is set together with the ceiling height. For the doors the stair opens onto see door and window sizes, and for accessible routes the accessibility ramp calculator.