The riser height (usually just “the rise”) is the vertical distance between two consecutive treads on a staircase: how far you have to step up each time. Its horizontal counterpart is the going, the usable depth of a tread.
Rise and going together decide whether a staircase walks pleasantly or whether you feel it every day. Steps that are too high cost effort; steps that are too low force an unnatural rhythm.
How to calculate it
The rise follows from the total height to be climbed divided by the number of risers — and that number is always a whole number.
Worked example: a floor-to-floor height of 2,800 mm (finished floor level to finished floor level).
- 2,800 / 15 = 186.7 mm per riser — that works comfortably.
- 2,800 / 14 = 200 mm per riser — steeper, but still within the domestic limit.
A stair with 15 risers has 14 goings: the top “step” is the upper floor itself.
Watch out: always work to finished floor levels. Measuring up before the screed and floor finish are in place gives you an odd step at the top or bottom — a classic trip hazard.
Limits and rules of thumb
For a private stair in a dwelling, Approved Document K in England and Wales sets a maximum rise of 220 mm, a minimum going of 220 mm and a maximum pitch of 42 degrees. Other jurisdictions set their own values, so always check the code that applies to you.
Alongside that sits the classic step formula:
> 2 x rise + 1 x going = roughly 550 to 700 mm
A stair with a 185 mm rise and a 250 mm going gives 620 mm — comfortably in range.
Practical points
- All risers equal. The most dangerous thing on a staircase is a single odd step. Your foot expects a dimension and does not find it.
- Open or closed. An open stair without riser boards has additional requirements on the maximum size of the gap, particularly with young children in the house.
- Floor finish on the treads changes the first and last riser if it is not applied everywhere.
- Headroom. Adequate clear headroom must remain above the pitch line — with a steep stair you run out of it faster than you expect.
Related terms
- Going
- Walking line
- Open riser staircase
- Spiral staircase
Learn more about building terms in our knowledge base at fredsdiyplans.com.