Staircase calculator and Part K checker
Rise, going, pitch and the 2R+G rule for a private stair (Part K).
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A private stair in a house must meet Approved Document K: a rise between 150 and 220 mm, a going between 220 and 300 mm, a pitch no steeper than 42 degrees and twice the rise plus the going between 550 and 700 mm.
Enter your floor to floor height and tread depth and the calculator suggests riser counts and checks each rule. It is handy for loft conversions, where the stair is often the hardest part to fit.
Questions people ask
What is the maximum pitch for a stair in a house?
42 degrees for a private stair under Part K.
How much headroom does a loft stair need?
2.0 m normally, or 1.9 m at the centre of a loft conversion stair, reducing to 1.8 m at the side.
What is the 2R+G rule?
Twice the rise plus the going should fall between 550 and 700 mm. It keeps each step comfortable to climb.
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