Stair rise and going
A geometry check. Not Building Regulations approval.
Method
Worked case: 180 mm rise, 250 mm going is 35.8° and 2R+G = 610 mm.
Approved Document K has its own limits. This page only reports the geometry.
What to write beside the result
A review can only check this figure if the inputs sit next to it. Write the value, the unit and the assumption the form used. A diameter in millimetres and a diameter in metres are not the same reading. A force in kilonewtons divided as if it were newtons is a thousand-fold error.
The result is the arithmetic on this page. It is not a utilisation, not a selected product, and not a clause from a standard. If the number is going into a shared container, name the page, the date and the inputs. The file-name checker does not read the calculation.
Logic: how this figure is built.
How to read a stair geometry
The page reports the angle and the 2R+G figure for the rise and going you type. A 180 mm rise and a 250 mm going is about 35.8° and 610 mm. Approved Document K has its own limits for rise, going and pitch. This page does not apply them.
Rise is the vertical distance between consecutive treads. Going is the horizontal distance. A nosing projection is not the going. A tapered tread has a going that changes across the width. The page is a straight flight.
2R+G is a rule of thumb used to compare stairs. It is not the regulation. A stair can meet 2R+G and still fail a going limit, or the reverse.
Use it to check a modelled flight before a specification comparison. Headroom, handrail height and a landing are not on this page.
- Related: slope
- setting-out logic
Last checked 3 October 2026. See the common-calculations note and the disclaimer.