What is the pitch of a stair?
The pitch of a stair is the angle, in degrees, at which the flight rises from the horizontal: how steep the stair is. In Dutch it is called the stijgingshoek.
Do not confuse pitch with riser height. The rise is a dimension in millimetres, the vertical step from one tread to the next. The going is the horizontal depth of a step. The pitch is the result of both:
tan(pitch) = rise / going
Two stairs with the same rise can therefore have very different pitches, depending on the going.
Worked examples
- England. Approved Document K limits the pitch of a private stair to 42°, alongside limits on rise and going. A 220 mm rise needs a going of about 244 mm to stay within 42°.
- Netherlands. Dutch rules allow a maximum rise of 188 mm with a minimum going of 220 mm for a dwelling stair, about 40.5°.
- Comfortable stair. A 175 mm rise with a 250 mm going gives 35°.
A shallower stair is only easier up to a point. A very shallow stair breaks your natural stride.
Application
- Design with rise and going, then check the angle. Regulations govern the dimensions and the step formula (2 x rise + going) decides whether the stair walks well.
- Degrees to percent. 45° equals a 100% gradient (1:1). Ramps are usually described as a gradient or ratio rather than an angle.
- Space versus comfort. A lower pitch needs a longer flight and a bigger stairwell opening.
- Check an existing stair. Divide the total rise by the total horizontal run and take the arctangent for the average pitch.
Common mistake: assuming a low rise automatically gives a gentle stair. With a short going, the pitch stays steep.
Related terms
- Riser height
- Going depth
- Stair step formula
- Walking line on a stair
- Shallow staircase
- Roof pitch
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