Staircase Rise & Going Calculator (UK Building Regs)

Staircase Design Guide (UK Building Regs Part K)

What do I need to know about Key Terms and Limits?

Staircase terminology: rise — the vertical height of each step. Going — the horizontal depth of each tread (front to back of usable step). Pitch — the angle of the staircase from horizontal. Total rise — floor-to-floor vertical height. UK Building Regulations Part K limits (private domestic stairs): maximum rise: 220mm per step. Minimum going: 220mm per step. Maximum pitch: 42°. Maximum 16 risers in a single flight (without a landing). Minimum headroom: 2000mm (2m) measured vertically. The relationship between rise and going is what determines whether a staircase feels comfortable and safe to use, rather than either measurement alone.

What do I need to know about The 2R + G Rule?

The most important comfort formula: 2 × Rise + Going should be between 550mm and 700mm. Ideal target: around 600-620mm. Why: this relates the step proportions to the natural human stride. Stairs that satisfy this rule feel comfortable to climb. Stairs that violate it feel awkward — either cramped (too little going) or stretched (too much going for the rise). Examples: rise 190mm, going 230mm: 2(190) + 230 = 610mm ✅ comfortable. Rise 220mm, going 220mm: 2(220) + 220 = 660mm — within the acceptable range, but steeper and less comfortable than a staircase closer to the lower end of the range.

What's the key thing to understand about Calculating Step Count?

Process: 1. Divide total rise by preferred individual rise to get number of risers. Total rise 2600mm ÷ 190mm = 13.7. Round to nearest whole number: 14 risers. 2. Recalculate exact rise: 2600 ÷ 14 = 185.7mm per riser. 3. Number of treads (goings) = risers minus 1 (the top step is the landing). 14 risers = 13 goings. 4. Going = available horizontal run ÷ number of goings. 3500mm ÷ 13 = 269mm per going. 5. Check 2R + G: 2(185.7) + 269 = 640mm — within range, comfortable. 6. Check pitch: arctan(rise/going) to confirm the resulting angle stays within the maximum 42° allowed under Part K.

What should I know about Other Requirements?

Headroom: minimum 2000mm vertical clearance above the pitch line. For loft conversions, often the tightest constraint. Reduced headroom (1900mm at edge) sometimes permitted for loft conversions under specific rules. Handrails: required on at least one side if stairs wider than 1000mm; both sides if wider than 1000mm. Handrail height: 900-1000mm above pitch line. Width: no minimum width in Part K for private stairs, but practically 600mm+ (800mm+ comfortable). Common stairs in flats: minimum 1000mm width, reflecting the higher traffic and shared-use nature of communal staircases compared to a private house.