UK Stair Code Requirements
The riser, going, headroom, width, handrail and guard limits for stairs in UK under Approved Document K — with how each compares to the US IRC, and the calculators that check them.
UK stair code at a glance
Stairs in UK are governed by Approved Document K. The limits below are the headline requirements — maximum riser, minimum going, headroom, width, handrail and guard heights — read straight from the same data the Stairs Calc stairs calculator checks against. Local authorities adopt and amend codes, so always confirm against your locally adopted edition before you build.
| Requirement | UK | US IRC (reference) | Reference |
|---|---|---|---|
| Maximum riser height | 8 11/16" | 7 11/16" | ADK 1.1 |
| Minimum riser height | 5 7/8" | — | ADK 1.1 |
| Minimum going (tread run) | 8 11/16" | 10" | ADK 1.1 |
| Minimum headroom | 6' 6 3/4" | 6' 8" | ADK 1.10 |
| Minimum guard height | 35 7/16" | 36" | ADK 3.3 |
| Baluster max sphere | 3 15/16" | 4 3/8" | ADK 3.3 |
| Handrail height | 35 7/16"–39 3/8" | 34"–38" | ADK 1.34 |
Edition referenced: Approved Document K.
How UK compares to other codes
The table below puts Approved Document K side by side with the US IRC and IBC, the UK, Canada, Australia, Germany and the wider international set. The UK row is highlighted. Switch the unit toggle in the header to read every limit in metric or imperial.
86 building codes across 6 regions. The 8 US/UK/EU codes are primary-source verified; international rows are indicative — confirm against your locally adopted code.
Swipe the table sideways to see all 11 metrics →
| Code | Max riser | Min riser | Min run (going) | Uniformity tolerance | Min headroom | Min width | Handrail height | Guard height | Guard trigger (drop) | Baluster max sphere | Max rise between landings |
|---|---|---|---|---|---|---|---|---|---|---|---|
| United States | |||||||||||
| US – Accessibility (ADA) | 7" | 4" | 11" | 3/8" | 6' 8" | 36" | 34"–38" | — | — | — | — |
| US – Commercial (IBC) | 7" | 4" | 11" | 3/8" | 6' 8" | 44" | 34"–38" | 42" | 30" | 4" | 12' |
| US – Residential (IRC) | 7 11/16" | — | 10" | 3/8" | 6' 8" | 36" | 34"–38" | 36" | 30" | 4 3/8" | 12' 7" |
| US – Workplace (OSHA) | 9 1/2" | — | 9 1/2" | — | 6' 8" | 22" | 30"–38" | 42" | — | — | — |
| Europe | |||||||||||
| Albania low confidence | 8 1/4" | 5 1/2" | 11 7/16" | — | 6' 2 13/16" | 35 7/16" | 35 7/16"–39 3/8" | 35 7/16" | — | — | 8' 3 3/16" |
| Austria high confidence | 7 1/16" | — | 10 5/8" | — | 6' 10 11/16" | 47 1/4" | 35 7/16"–43 5/16" | 39 3/8" | — | 4 3/4" | 11' 9 3/4" |
| Belarus medium confidence | 5 7/8" | — | 9 13/16" | — | 6' 6 3/4" | 35 7/16" | 35 7/16"–39 3/8" | 35 7/16" | — | 3 15/16" | 8' 10 5/16" |
| Belgium medium confidence | 7 1/16" | — | 7 7/8" | — | — | 31 1/2" | 35 7/16"–39 3/8" | 43 5/16" | — | 4 5/16" | — |
| Bosnia and Herzegovina low confidence | 7 1/2" | — | 9 13/16" | — | 7' 2 5/8" | 43 5/16" | 35 7/16"–39 3/8" | 39 3/8" | — | 4 3/4" | 11' 2 5/8" |
| Bulgaria medium confidence | 8 11/16" | — | 9 13/16" | — | 6' 6 3/4" | 47 1/4" | 35 7/16"–39 3/8" | 35 7/16" | — | 3 9/16" | 3' 11 1/4" |
| Croatia medium confidence | 7 1/2" | — | 9 13/16" | — | 6' 10 11/16" | 43 5/16" | 35 7/16"–35 7/16" | 39 3/8" | — | 5 1/2" | — |
| Cyprus high confidence | 7 1/16" | 5 5/16" | 11" | — | 6' 10 11/16" | 47 1/4" | 27 9/16"–35 7/16" | 43 5/16" | — | 3 15/16" | 10' 7 9/16" |
| Czechia high confidence | 7 1/2" | 5 7/8" | 8 1/4" | — | 6' 10 11/16" | 35 7/16" | 35 7/16"–47 1/4" | 39 3/8" | — | 4 3/4" | 10' 7 9/16" |
| Denmark medium confidence | 7 1/16" | — | 9 13/16" | — | 6' 10 11/16" | 39 3/8" | 31 1/2"–31 1/2" | 39 3/8" | — | 3 1/2" | — |
| Estonia low confidence | 6 5/16" | — | 10 5/8" | — | 6' 10 11/16" | 35 7/16" | 35 7/16"–35 7/16" | 39 3/8" | — | 4 5/16" | — |
| Finland high confidence | 7 1/2" | — | 9 13/16" | — | 6' 4 3/4" | 33 7/16" | 35 7/16"–39 3/8" | 35 7/16" | — | 3 15/16" | — |
| France medium confidence | 8 1/4" | 6 5/16" | 8 1/4" | — | 6' 2 13/16" | 27 9/16" | 31 1/2"–39 3/8" | 39 3/8" | — | 4 5/16" | 17' 2 11/16" |
| Germany (DIN 18065) | 7 7/8" | 5 1/2" | 9 1/16" | 3/16" | 6' 6 3/4" | 31 1/2" | 35 7/16"–43 5/16" | 35 7/16" | 39 3/8" | 4 5/16" | — |
| Greece high confidence | 7 1/16" | 5 1/8" | 9 13/16" | — | 7' 2 5/8" | 35 7/16" | 35 7/16"–39 3/8" | 39 3/8" | — | 5 7/8" | 11' 9 3/4" |
| Hungary high confidence | 7 7/8" | — | 10 1/4" | — | 6' 6 3/4" | 31 1/2" | 35 7/16"–39 3/8" | 37 3/8" | — | 4 3/4" | 9' 10 1/8" |
| Iceland high confidence | 7 1/16" | 4 3/4" | 9 7/16" | — | 6' 10 11/16" | 35 7/16" | 31 1/2"–35 7/16" | 35 7/16" | — | 3 1/2" | 10' 9 15/16" |
| Ireland high confidence | 8 11/16" | — | 8 11/16" | — | 6' 6 3/4" | 31 1/2" | 35 7/16"–39 3/8" | 35 7/16" | — | 3 15/16" | 11' 6 9/16" |
| Italy medium confidence | 6 7/8" | — | 11 13/16" | — | 6' 10 11/16" | 31 1/2" | 35 7/16"–39 3/8" | 39 3/8" | — | 3 15/16" | — |
| Latvia high confidence | 7 1/16" | 4 3/4" | 9 7/16" | — | — | 35 7/16" | 35 7/16"–39 3/8" | 43 5/16" | — | 4 3/4" | — |
| Lithuania high confidence | 7 7/8" | — | 9 13/16" | — | 6' 6 3/4" | 35 7/16" | 35 7/16"–39 3/8" | 35 7/16" | — | 4 3/4" | 10' 1/2" |
| Luxembourg medium confidence | 6 11/16" | — | 9 13/16" | — | 7' 2 5/8" | 47 1/4" | 35 7/16"–39 3/8" | 35 7/16" | — | 3 15/16" | — |
| Malta medium confidence | 8 11/16" | — | 8 11/16" | — | 6' 6 3/4" | 35 7/16" | 35 7/16"–39 3/8" | 35 7/16" | — | 3 15/16" | 25' 11 13/16" |
| Moldova high confidence | 5 7/8" | — | 9 13/16" | — | 6' 6 3/4" | 35 7/16" | 35 7/16"–39 3/8" | 47 1/4" | — | 3 15/16" | 8' 10 5/16" |
| Montenegro medium confidence | 7 1/16" | — | 11" | — | 7' 2 5/8" | 47 1/4" | 35 7/16"–39 3/8" | 43 5/16" | — | 3 15/16" | 7' 1 1/16" |
| Netherlands high confidence | 7 3/8" | — | 8 11/16" | — | 7' 6 9/16" | 31 1/2" | 31 1/2"–39 3/8" | 39 3/8" | — | 3 15/16" | 13' 1 1/2" |
| North Macedonia medium confidence | 7 1/16" | — | 11" | — | 6' 10 11/16" | 43 5/16" | 35 7/16"–39 3/8" | 39 3/8" | — | 3 15/16" | 10' 7 9/16" |
| Norway high confidence | 7 11/16" | — | 9 13/16" | — | 6' 6 3/4" | 31 1/2" | 27 9/16"–35 7/16" | 35 7/16" | — | 3 15/16" | 10' 9 15/16" |
| Poland high confidence | 7 1/2" | — | 9 13/16" | — | 6' 6 3/4" | 31 1/2" | 35 7/16"–39 3/8" | 35 7/16" | — | 4 3/4" | — |
| Portugal medium confidence | 7 5/8" | — | 9 13/16" | — | 7' 10 1/2" | 31 1/2" | 33 7/16"–35 7/16" | 43 5/16" | — | 3 9/16" | 7' 10 1/2" |
| Romania high confidence | 6 7/8" | — | 10 5/8" | — | 6' 6 3/4" | 37 3/8" | 35 7/16"–35 7/16" | 35 7/16" | — | 3 15/16" | — |
| Russia high confidence | 8 11/16" | 1 15/16" | 9 13/16" | — | 7' 2 5/8" | 41 5/16" | 35 7/16"–39 3/8" | 35 7/16" | — | 3 15/16" | 11' 6 9/16" |
| Serbia high confidence | 7 1/16" | — | 11" | — | 7' 2 5/8" | 47 1/4" | 35 7/16"–39 3/8" | 43 5/16" | — | 4 3/4" | 10' 1/2" |
| Slovakia high confidence | 7 7/8" | 5 7/8" | 8 1/4" | — | 6' 10 11/16" | 35 7/16" | 35 7/16"–47 1/4" | 39 3/8" | — | 4 3/4" | 10' 7 9/16" |
| Slovenia medium confidence | 7 1/2" | — | 9 13/16" | — | 6' 6 3/4" | 31 1/2" | 35 7/16"–39 3/8" | 39 3/8" | — | 4 3/4" | — |
| Spain high confidence | 7 7/8" | — | 8 11/16" | — | 6' 10 11/16" | 31 1/2" | 35 7/16"–43 5/16" | 35 7/16" | — | 3 15/16" | 10' 6" |
| Sweden high confidence | 7 7/8" | — | 9 13/16" | — | 6' 6 3/4" | 35 7/16" | 35 7/16"–39 3/8" | 35 7/16" | — | 3 15/16" | — |
| Switzerland medium confidence | 7 1/2" | — | 10 1/4" | — | 6' 10 11/16" | 35 7/16" | 33 7/16"–35 7/16" | 39 3/8" | — | 4 3/4" | — |
| Turkey high confidence | 7 1/16" | — | 10 5/8" | — | 6' 10 11/16" | 47 1/4" | 35 7/16"–39 3/8" | 43 5/16" | — | 3 15/16" | 9' 10 1/8" |
| UK (Part K) | 8 11/16" | 5 7/8" | 8 11/16" | — | 6' 6 3/4" | — | 35 7/16"–39 3/8" | 35 7/16" | 23 5/8" | 3 15/16" | — |
| Ukraine medium confidence | 7 7/8" | — | 7 1/16" | — | — | 41 5/16" | 35 7/16"–39 3/8" | 47 1/4" | — | — | — |
| Asia-Pacific | |||||||||||
| Afghanistan low confidence | 7 11/16" | — | 10" | — | 6' 8" | 36" | 34"–38" | 36" | — | 4" | 12' |
| Australia (NCC) | 7 1/2" | 4 1/2" | 9 7/16" | 3/8" | 6' 6 3/4" | — | 34 1/16"–43 5/16" | 39 3/8" | 39 3/8" | 4 15/16" | — |
| Bangladesh medium confidence | 9 1/16" | — | 13" | — | 7' 1" | 44 1/8" | 33 7/8"–37 13/16" | 41 5/16" | — | 3 15/16" | 12' |
| China high confidence | 6 7/8" | — | 10 1/4" | — | 7' 2 5/8" | 43 5/16" | 35 7/16"–39 3/8" | 47 1/4" | — | 4 5/16" | 10' 4" |
| India medium confidence | 7 1/2" | — | 9 13/16" | — | 7' 2 5/8" | 35 7/16" | 35 7/16"–39 3/8" | 35 7/16" | — | 3 15/16" | 7' 5 3/4" |
| Indonesia low confidence | 7 7/8" | — | 11" | — | 6' 6 3/4" | 47 1/4" | 34 1/16"–38" | 39 3/8" | — | 3 15/16" | — |
| Japan high confidence | 9 1/16" | — | 5 7/8" | — | 6' 10 11/16" | 29 1/2" | 35 7/16"–39 3/8" | 43 5/16" | — | 4 5/16" | 13' 1 1/2" |
| Malaysia high confidence | 7 1/16" | — | 10 1/16" | — | 6' 6 3/4" | — | 32 1/2"–35 7/16" | 39 3/8" | — | — | 13' 11 5/16" |
| Myanmar high confidence | 8" | 4" | 10" | — | 7' | 36" | 36"–39 3/8" | 36" | — | 4" | — |
| Nepal high confidence | 7 1/2" | — | 9 13/16" | — | 6' 6 3/4" | 35 7/16" | 35 7/16"–35 7/16" | 39 3/8" | — | — | — |
| Pakistan medium confidence | 7 1/16" | — | 9 1/16" | — | 6' 10 11/16" | 47 1/4" | 35 7/16"–39 3/8" | — | — | — | — |
| Philippines high confidence | 7 7/8" | — | 9 13/16" | — | 6' 6 3/4" | 29 1/2" | 31 1/2"–35 7/16" | 43 5/16" | — | — | 11' 9 3/4" |
| South Korea high confidence | 7 1/16" | — | 10 1/4" | — | 6' 10 11/16" | 47 1/4" | 33 7/16"–33 7/16" | 47 1/4" | — | 3 15/16" | 9' 10 1/8" |
| Thailand high confidence | 7 7/8" | — | 8 11/16" | — | 6' 2 13/16" | 31 1/2" | 35 7/16"–39 3/8" | — | — | — | 9' 10 1/8" |
| Uzbekistan medium confidence | 6 11/16" | 5 1/8" | 11" | — | — | 41 5/16" | 35 7/16"–39 3/8" | 35 7/16" | — | — | 10' 1/2" |
| Vietnam high confidence | 7 1/2" | 1 15/16" | 9 13/16" | — | 6' 6 3/4" | 27 9/16" | 35 7/16"–39 3/8" | 35 7/16" | — | 3 15/16" | — |
| Americas | |||||||||||
| Argentina high confidence | 7 1/16" | — | 9 1/16" | — | 6' 6 3/4" | 39 3/8" | 33 7/16"–39 3/8" | 33 7/16" | — | 4 3/4" | 12' 4 13/16" |
| Brazil medium confidence | 7 1/16" | 6 5/16" | 11" | — | 6' 10 11/16" | 47 1/4" | 27 9/16"–36 1/4" | 43 5/16" | — | 4 5/16" | 10' 6" |
| Canada (NBC) | 7 7/8" | 4 15/16" | 10 1/16" | 3/8" | 6' 4 3/4" | 33 7/8" | 34 1/16"–42 1/8" | 35 7/16" | 23 5/8" | 3 15/16" | 12' 1 11/16" |
| Colombia high confidence | 7 1/16" | 3 15/16" | 11" | — | 6' 6 3/4" | 29 1/2" | 27 9/16"–35 7/16" | — | — | — | 11' 5 13/16" |
| Mexico high confidence | 7 1/16" | 3 15/16" | 9 13/16" | — | — | 35 7/16" | 35 7/16"–39 3/8" | 35 7/16" | — | — | 8' 10 5/16" |
| Peru high confidence | 7 1/16" | — | 9 13/16" | — | 6' 10 11/16" | 35 7/16" | 33 7/16"–39 3/8" | 39 3/8" | — | 5 7/8" | 10' 1/2" |
| Venezuela medium confidence | 7 7/8" | 5 7/8" | 10 1/4" | — | — | 47 1/4" | 29 1/2"–35 7/16" | 35 7/16" | — | 5 7/8" | 7' 10 1/2" |
| Middle East | |||||||||||
| Iran medium confidence | 7 1/16" | 3 15/16" | 11" | — | 6' 8 11/16" | 43 5/16" | 33 7/16"–35 7/16" | 35 7/16" | — | 4 5/16" | 12' 1 11/16" |
| Iraq low confidence | 7 7/8" | — | 9 13/16" | — | — | — | 35 7/16"–39 3/8" | — | — | — | — |
| Saudi Arabia medium confidence | 7 7/8" | — | 9 13/16" | — | 6' 6 3/4" | 35 7/16" | 34 1/16"–38" | 42" | — | 3 15/16" | 12' |
| Yemen low confidence | 7 7/8" | — | 9 13/16" | — | 6' 6 3/4" | 35 7/16" | 34 1/16"–38" | 42" | — | 3 15/16" | 12' |
| Africa | |||||||||||
| Algeria low confidence | 6 5/16" | — | 12 5/8" | — | — | 31 1/2" | 35 7/16"–39 3/8" | 39 3/8" | — | 4 5/16" | — |
| Angola medium confidence | 7 5/8" | — | 9 13/16" | — | — | 31 1/2" | 35 7/16"–39 3/8" | — | — | — | — |
| DR Congo low confidence | 8 1/4" | 6 5/16" | 8 1/4" | — | 6' 2 13/16" | 27 9/16" | 35 7/16"–39 3/8" | 39 3/8" | — | 4 5/16" | — |
| Egypt high confidence | 6 11/16" | — | 10 5/8" | — | 6' 10 11/16" | 43 5/16" | 35 7/16"–47 1/4" | 35 7/16" | — | 5 7/8" | 7' 9 11/16" |
| Ethiopia low confidence | 7 7/8" | — | 9 13/16" | — | 7' 10 1/2" | — | 35 7/16"–39 3/8" | — | — | — | — |
| Ghana medium confidence | 7 1/2" | — | 9 13/16" | — | 6' 6 3/4" | 35 7/16" | 35 7/16"–39 3/8" | 39 3/8" | — | 3 15/16" | — |
| Kenya medium confidence | 7 1/2" | — | 9" | — | 6' 9" | 30" | 35 7/16"–39 3/8" | 33" | — | 5" | 10' |
| Morocco low confidence | 6 5/16" | — | 11" | — | — | 47 1/4" | 31 1/2"–39 3/8" | 35 7/16" | — | — | — |
| Mozambique medium confidence | 7 5/8" | — | 9 13/16" | — | — | 31 1/2" | 35 7/16"–39 3/8" | — | — | — | — |
| Nigeria high confidence | 7 1/16" | 3 15/16" | 11" | — | 6' 10 11/16" | 36" | 34"–38" | 43 5/16" | — | 5 7/8" | 9' 10 1/8" |
| South Africa medium confidence | 7 7/8" | — | 9 13/16" | — | 6' 10 11/16" | 29 1/2" | 33 7/16"–39 3/8" | 39 3/8" | — | 3 15/16" | 9' 10 1/8" |
| Sudan low confidence | 7 7/8" | — | 9 13/16" | — | — | — | 35 7/16"–39 3/8" | — | — | — | — |
| Tanzania low confidence | 7 1/2" | — | 9" | — | 6' 9" | 30" | 33"–39 3/8" | 33" | — | 5" | — |
| Uganda high confidence | 6 7/8" | — | 9 1/16" | — | 6' 10 11/16" | 35 7/16" | 33 1/16"–39 3/8" | 35 7/16" | — | 4 15/16" | 8' 7/16" |
IRC vs IBC at a glance
| Limit | IRC (residential) | IBC (commercial) |
|---|---|---|
| Max riser | 7¾″ | 7″ |
| Min tread/run | 10″ | 11″ |
| Min width | 36″ | 44″ |
| Guard height | 36″ | 42″ |
| Rise between landings | 12′-7″ | 12 ft |
Check a UK stair against Approved Document K
Every Stairs Calc calculator lets you select a jurisdiction and checks your dimensions live. Pick UK in the code panel to validate your riser, going and headroom against Approved Document K, then size the handrail and baluster spacing to its guard rules.
Calculators that honor UK code
Stairs Calculator Enter one measurement — your total rise — and get a complete, code‑compliant stair layout with a 3D diagram, stringer cut list, and printable template. Free, instant, in inches or millimeters. Stair Rise and Run Calculator Turn one total‑rise measurement into equal risers and runs that meet code — with the comfort rules (2R+T and Rise+Run) checked for you. Handrail Length Calculator Get the handrail length for your stairs — the sloped grip run plus the code-required top and bottom extensions — with mounting height and grip diameter checked against your building code. Baluster Spacing Calculator Enter your railing length and spindle width to get the number of balusters, the exact even gap and center‑to‑center spacing — checked against your code’s 4‑inch sphere rule.
Written by the Stairs Calc editorial team. Methodology and code references: see our methodology.
Built and maintained by builders, drafters and engineers who plan stairs for a living — every code limit is transcribed from the published standard and cited to its exact section.
Last reviewed 2026-06-20 against Approved Document K
Stairs Calc gives accurate geometry and checks it against published building-code limits, but results are estimates for planning. Codes are adopted and amended locally and change over time. Always confirm dimensions against your local adopted code and a licensed professional before you build.