The US 7-11 rule
The 7-11 rule is a widely used shorthand for comfortable residential stair proportions: a riser height around 7 inches (roughly 178mm) paired with a tread going around 11 inches (roughly 280mm). It is a rule of thumb, not a code citation in itself — actual US residential code language (commonly derived from the IRC) usually expresses maximum riser height and minimum tread going as separate numeric limits, and the 7-11 combination happens to sit comfortably inside those limits for most jurisdictions.
| Element | 7-11 rule figure | Typical code limit (confirm locally) |
|---|---|---|
| Riser height | ≈7in / 178mm | Maximum around 7.75in / 196-200mm |
| Tread going (depth) | ≈11in / 280mm | Minimum around 10in / 254mm |
The UK approach: pitch angle plus separate limits
UK Building Regulations (Approved Document K for most dwellings) generally work from a maximum pitch angle for a private stair, often cited as around 42 degrees, combined with its own riser and going limits (commonly riser up to roughly 220mm and going at least roughly 220mm for a private stair, subject to the twice-rise-plus-going relationship also being satisfied). Always check the current edition of the relevant Approved Document or local equivalent, since numeric limits are periodically revised.
| Element | Typical UK private stair guidance (confirm current regs) |
|---|---|
| Maximum pitch | ≈42 degrees |
| Maximum riser | ≈220mm / 8.7in |
| Minimum going | ≈220mm / 8.7in |
| Twice rise + going rule | Often required to fall within roughly 550-700mm / 21.7-27.6in |
Codes change — treat these as starting points
Numeric limits in both US and UK guidance are periodically revised and can vary for public buildings, means of escape, or accessible routes. Confirm the current figures for your jurisdiction and building type before finalising a stair design.
Why the two approaches usually agree in practice
A 7-11 rule stair works out to a pitch of roughly 32-33 degrees, comfortably under the roughly 42-degree UK maximum, and its riser and going figures sit inside typical UK numeric limits too. In other words, a stair built to the American rule of thumb will generally also satisfy UK-style limits, and a stair built to a moderate UK pitch will generally also land near the American comfort rule — the two systems describe overlapping, not conflicting, territory.
Worked comparison
| Riser | Going | Approx. pitch | Fits 7-11 rule? | Fits typical UK limits? |
|---|---|---|---|---|
| 178mm / 7.0in | 280mm / 11.0in | ≈32.4° | Yes (by definition) | Yes |
| 190mm / 7.5in | 250mm / 9.8in | ≈37.2° | Close | Yes, if going ≥ min |
| 200mm / 7.9in | 220mm / 8.7in | ≈42.3° | No — riser high, going shallow | Borderline — check current max pitch |
Know your numbers in 30 seconds
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Open the stair runner calculatorSteeper stairs: when they're allowed
Both systems permit steeper geometry in specific situations — commonly loft or attic conversions where floor space is limited — sometimes via alternating tread stairs or space-saver designs with their own separate numeric rules rather than the standard private-stair limits. If you are designing to a constrained space, check whether a specific steep-stair or alternating-tread provision applies before assuming the standard limits are your only option.
Common mistakes comparing the two systems
- Treating the 7-11 rule as a legal code citation rather than a rule of thumb that happens to satisfy most codes.
- Applying UK private-stair limits to a public building or escape route, where different numbers usually apply.
- Forgetting the UK twice-rise-plus-going check, which can catch a combination that passes the individual riser and going limits separately.
- Assuming a steep loft-stair exception applies to a main staircase.
- Not rechecking current Approved Document figures, since numeric limits are periodically revised.
Standard rise and run combinations, side by side
| Riser | Going | Pitch | Reads as |
|---|---|---|---|
| 165mm / 6.5in | 300mm / 11.8in | ≈28.8° | Very gentle, main stair in a larger house |
| 178mm / 7.0in | 280mm / 11.0in | ≈32.4° | Classic US 7-11 rule |
| 190mm / 7.5in | 250mm / 9.8in | ≈37.2° | Common UK private-stair proportion |
| 200mm / 7.9in | 220mm / 8.7in | ≈42.3° | Steep, near UK maximum private-stair pitch |
| 220mm / 8.7in | 220mm / 8.7in | ≈45.0° | Space-saver or loft-stair territory |
On a recent Victorian terrace refurbishment I measured an existing flight at 195mm riser and 235mm going - a combination that would not be chosen from scratch today but has stood for well over a century, which is a reminder that 'standard' figures are a design target for new work, not a retrospective test that every existing stair must pass. Where you are refurbishing rather than rebuilding, the practical question is usually whether the existing geometry is safe and consistent, not whether it matches a modern standard exactly.
Standard geometry and stair runner fitting
Standard rise and run also determines how a stair runner carpet sits on the flight, because riser height and tread going are exactly the two numbers a runner has to wrap around on every step. A steeper stair (taller riser, shallower going, closer to the UK 42-degree maximum) uses more carpet per step than a gentler 7-11 rule stair covering the same total rise, since the riser face takes up proportionally more of each step's total length. When I am quoting a runner job I always ask for riser and going figures rather than just a step count, and a stair runner calculator will ask for the same thing - the same measurements that determine whether your stairs meet standard rise-and-run guidance also determine how many metres of stair runner carpet you need to order.
Quick reference: rise and run by stair type
- Main household stair: gentler end of the range, often 165-180mm riser with 250-300mm going, for everyday comfort.
- Secondary or back stair: mid-range, commonly 180-190mm riser with 220-250mm going.
- Loft or attic stair: steeper, sometimes using alternating-tread or space-saver geometry outside standard private-stair limits.
- Exterior or garden steps: usually shallower again than any interior standard, often with a lower riser and deeper going for outdoor safety and drainage.
Whatever you decide, get the numbers first: the stair runner calculator doubles as a stair runner length calculator, adding nosing wrap, landings, winders, pattern repeat and waste so you order the right length the first time.
Frequently asked questions
What is the 7-11 rule for stairs?
A rule of thumb pairing a roughly 7-inch (178mm) riser with an roughly 11-inch (280mm) tread going, widely used in US residential stair design as a comfortable, code-friendly combination.
What is the maximum stair pitch in the UK?
Commonly cited as around 42 degrees for a private stair under UK Building Regulations, though you should confirm the current Approved Document K figures for your specific project.
Do the US 7-11 rule and UK regulations agree?
They usually overlap in practice — a 7-11 rule stair generally satisfies typical UK numeric limits and pitch maximums too, even though the two systems are expressed differently.
What is the twice-rise-plus-going rule?
A UK check (sometimes written as 2R + G) that riser height doubled, plus tread going, should fall within a set range, commonly cited as roughly 550-700mm, in addition to the individual riser and going limits.
Can stairs be steeper than the standard limits?
Sometimes, for loft or attic stairs with limited space, where alternating tread stairs or space-saver designs are permitted under separate rules — check whether that exception applies before assuming standard limits are mandatory.
Is a comfortable stair pitch always the maximum allowed pitch?
No. The maximum pitch is a legal ceiling, not a comfort target. A pitch well under the maximum, closer to the 7-11 rule's roughly 32-33 degrees, is generally more comfortable for everyday use.
Why do riser and going limits get checked separately from pitch?
Because two very different riser/going combinations can produce the same pitch angle, so codes generally check riser height, going, and sometimes the combined relationship, not pitch alone.
Do these standard figures apply to public buildings?
Not necessarily. Public buildings, means-of-escape stairs and accessible routes commonly have their own, often stricter, numeric limits, separate from private residential stair guidance.
Know your numbers in 30 seconds
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