Minimum code requirements for safe stairs — international overview
A compact summary of the most consistent stair safety rules across international codes (IBC, IRC, BS, EU norms). Exact values vary, but the underlying principles remain the same.
Riser and tread rules
- Max riser height: 190–200 mm
- Min tread depth (going): 250–280 mm
- Open risers: gap usually limited to 100 mm
- Uniformity: variation within a flight usually ≤ 6–8 mm
These values define the basic comfort and safety envelope for most stair types.
Headroom
Minimum clear headroom is almost universally around 2.0–2.1 m. Anything under 1950 mm is typically non-compliant except for secondary spaces.
Handrails
- Height: 900–1000 mm above pitch line.
- Continuous for full flight, including around landings.
- Return to wall or newel post to avoid catching clothing.
- Grip size suitable for a closed hand (usually 30–50 mm diameter).
Width requirements
Residential private stairs: 800–900 mm common. Public/commercial stairs: 1100–1800 mm depending on occupancy and escape route requirements.
Landings
- No flight should rise more than 3.0–3.7 m without a landing.
- Landing width must be at least equal to stair width.
- Doors cannot swing over steps unless exceptionally permitted.
Ergonomic formula
Most codes refer to the common comfort ratio:
2 × rise + run ≈ 600–640 mm