Staircase Design & Rise/Going Calculator
Calculate the correct rise, going, and number of steps for any staircase. Ensures Building Regulations compliance for pitch, headroom, and step dimensions.
Staircase Design Guide
Building Regulations Part K
For private domestic stairs (Part K 2013): riser height: 150mm minimum, 220mm maximum. Going: 220mm minimum. Pitch: maximum 42°. The rule: 2 × rise + going should be between 550-700mm (the 'comfort formula'). For the optimum staircase: rise 170-175mm, going 250-260mm. 2×170+260 = 600mm — centre of the comfort zone. Headroom: minimum 2000mm measured vertically from the pitch line. Handrail: required on at least one side if stair is 1m or wider; both sides if over 1m. Height: 900mm minimum from pi
Calculating Step Dimensions
Finding the right number of steps: divide total rise by approximate desired riser (175mm). Round to nearest whole number. Actual riser = total rise / number of risers. Going = available going / (number of risers − 1). Note: number of goings = number of risers − 1 (there is always one fewer tread than riser). Example: 2600mm rise, 3200mm available going. At 175mm target riser: 2600/175 = 14.86 → try 15 risers. Actual riser: 2600/15 = 173.3mm ✓. Going: 3200/14 = 228.6mm — below the 220mm minimum ✓
Winders and Space-Saving Stairs
Space-saving options: space-saver (paddle) stairs: alternating deep and shallow treads. Maximum pitch 55°. Only suitable for access to single room (loft). Winders: triangular treads that turn the stair direction. Complex to construct — must maintain minimum going at centreline of the stair. Minimum 50mm going at the narrow end. Spiral stairs: compact, but limited accessibility. Must meet minimum 150mm going at inner edge. All spiral stairs require planning if used as primary access. Building Con
Stringer and Materials
Closed stringer: solid timber with housing for treads and risers. Traditional, clean look. Open stringer (cut stringer): timber with notches cut for each step — treads visible from the side. Contemporary look. Stringer length = √(total_rise² + total_going²). This is the hypotenuse of the stair triangle. Materials: domestic stairs — softwood (pine, spruce) is standard for painted finish. Hardwood (oak, ash) for natural finish — expensive but durable. Engineered oak: more stable than solid, less e
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