Staircase Regulations UK: Rise, Going, Pitch and Number of Steps
A floor to floor height of 2,600 mm needs 14 risers of about 186 mm each, with 13 treads, if you want a comfortable rise of about 190 mm. For a private stair, Approved Document K allows a rise of up to 220 mm, a going of at least 220 mm and a pitch of up to 42 degrees, and the rise and going should satisfy 2 × rise + going = 550 to 700 mm. The stair calculator works out the steps for your own height and checks them against these limits.
Steps for each floor to floor height
With a preferred rise of about 190 mm and a going of 250 mm, and for the steepest rise the regulations allow:
| Floor to floor height | Risers at 190 mm (rise) | Pitch (250 mm going) | Length on plan | Risers at the 220 mm limit (rise) |
|---|---|---|---|---|
| 2,200 mm | 12 (183.3 mm) | 36.3° | 2.75 m | 10 (220.0 mm) |
| 2,300 mm | 13 (176.9 mm) | 35.3° | 3.00 m | 11 (209.1 mm) |
| 2,400 mm | 13 (184.6 mm) | 36.4° | 3.00 m | 11 (218.2 mm) |
| 2,500 mm | 14 (178.6 mm) | 35.5° | 3.25 m | 12 (208.3 mm) |
| 2,600 mm | 14 (185.7 mm) | 36.6° | 3.25 m | 12 (216.7 mm) |
| 2,700 mm | 15 (180.0 mm) | 35.8° | 3.50 m | 13 (207.7 mm) |
| 2,800 mm | 15 (186.7 mm) | 36.7° | 3.50 m | 13 (215.4 mm) |
| 3,000 mm | 16 (187.5 mm) | 36.9° | 3.75 m | 14 (214.3 mm) |
| 3,200 mm | 17 (188.2 mm) | 37.0° | 4.00 m | 15 (213.3 mm) |
The number of treads is one fewer than the risers, because the top riser lands on the upper floor.
How the going changes the pitch
For the 2,600 mm height with 14 risers of 185.7 mm:
| Going | Pitch | 2 × rise + going | Meets Part K? |
|---|---|---|---|
| 200 mm | 42.9° | 571 mm | No: the going is under 220 mm; the pitch is over 42° |
| 220 mm | 40.2° | 591 mm | Yes |
| 230 mm | 38.9° | 601 mm | Yes |
| 240 mm | 37.7° | 611 mm | Yes |
| 250 mm | 36.6° | 621 mm | Yes |
| 260 mm | 35.5° | 631 mm | Yes |
| 280 mm | 33.6° | 651 mm | Yes |
| 300 mm | 31.8° | 671 mm | Yes |
The Building Regulations for a private stair
- Rise: 220 mm at most. The rise is the height from one tread to the next.
- Going: 220 mm at least. The going is the depth of the tread, measured from the front of one tread to the next.
- Pitch: 42 degrees at most. A steeper stair is an accident risk.
- 2 × rise + going: between 550 mm and 700 mm, a comfortable stride.
- Uniformity: every riser the same height and every going the same depth in a flight, with only a small tolerance (up to 5 mm between adjacent steps).
- Headroom: 2.0 m of clear height above the pitch line.
- Handrail: on at least one side, 900 to 1,000 mm above the pitch line, and on both sides if the stair is 1 m wide or more.
- Guarding: at least 900 mm high on a stair and 1,100 mm on a landing where there is a drop, with no gap that a 100 mm sphere can pass through.
Other kinds of stair, such as a stair in a public or shared building, and loft conversion stairs, have other rules, and the regulations differ in Scotland, Wales and Northern Ireland. Building control checks a new stair, so talk to them before you start.
How to design a comfortable stair
- Choose the rise first, about 170 to 190 mm, and divide the height into whole steps.
- Choose a going of 250 to 280 mm if you have the room. A deeper going makes a gentler stair, but the stair is longer.
- Check the length on plan, the headroom and where the stair arrives on the upper floor: a stair that is too long may not fit.
- If the stair is too long for the space, a winder or a landing can turn it. Winders have their own rules for the going.
- Measure the height from finished floor to finished floor, including the floor coverings.
A stair that fits the regulations is the minimum. For a safe stair, choose a rise at the lower end, a good going, a handrail that is easy to grip and good lighting. This guide is general advice: your building control officer decides what is acceptable.
Frequently asked questions
What are the Building Regulations for stairs?
For a private stair in a house (Approved Document K, England): a maximum rise of 220 mm, a minimum going of 220 mm, a maximum pitch of 42 degrees, and 2 × rise + going between 550 and 700 mm, with 2.0 m of headroom, a handrail and guarding.
How many steps do I need for a staircase?
Divide the floor to floor height by the rise you want and round up. A height of 2,600 mm with a rise of about 190 mm gives 14 risers (13 treads) of 185.7 mm. At the maximum rise of 220 mm it is 12 risers.
What is the 2R + G rule for stairs?
Twice the rise plus the going should be between 550 and 700 mm. A rise of 186 mm and a going of 250 mm make 621 mm, which is comfortable.
What is the minimum going of a stair?
220 mm for a private stair. A going of 220 mm with a rise of 186 mm gives a pitch of 40.2°; the pitch limit of 42° is reached with a shorter going, such as 200 mm (42.9°).
How much headroom does a staircase need?
At least 2.0 m of clear headroom above the pitch line (the line through the front edges of the treads) for the whole flight. Loft conversions have a lower allowance in some cases: ask building control.
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and check the Building Regulations and any planning rules for anything structural or close to a boundary.