Staircase Calculator
Design a comfortable, code-friendly staircase from the total height it must climb. Get the number of steps, the rise of each, and a check against the comfort rules builders use — so the stairs feel right underfoot.
How to use this calculator
- Enter the total height from finished floor to finished floor.
- Set your preferred rise (17–19 cm feels natural) and going (tread depth).
- Check the comfort rules — the calculator flags anything outside builder norms.
Formula used
The height must divide into equal risers — you can't have a different final step, so the rise adjusts to fit a whole number of steps. Comfort rules: 2×rise + going ≈ 60–66 cm, and rise × going ≈ 450 cm².
Example calculation
280 cm floor-to-floor at ~18 cm rise: 280 ÷ 18 = 15.6 → 16 steps, each 17.5 cm.
With a 25 cm going: 2×17.5 + 25 = 60 cm (comfortable ✓), and the run spans 15 treads × 25 = 375 cm.
What makes a staircase feel right
Comfortable stairs obey a relationship between rise and going that matches human stride: too steep (high rise, shallow going) and they're tiring and unsafe to descend; too shallow and they feel like a slope you keep mis-stepping on. The centuries-old "2R + G ≈ 63 cm" rule captures this — it's the horizontal distance a stride naturally covers as you climb.
The non-negotiable constraint is equal risers: because people build a subconscious rhythm on the first two steps, a final step of a different height is a genuine trip hazard, so the rise is always chosen to divide the total height evenly. Building codes then set hard limits — maximum rise, minimum going, headroom and handrail rules — that any real staircase must satisfy on top of the comfort math.
Why use this calculator?
- Get equal risers automatically from any floor-to-floor height.
- Comfort checks (2R+G and rise×going) flag awkward stairs before you cut wood.
- See the total run so you know if the staircase fits the space.
Frequently asked questions
What is a comfortable stair rise?
17–19 cm per step is the comfortable range for homes, with ~18 cm ideal. Below 15 cm feels shuffling; above 20 cm is tiring and, in most codes, not permitted for regular stairs.
What is the 2R + G rule?
A stair-comfort formula: twice the rise plus the going should total about 60–66 cm (the classic figure is 63). It matches the natural stride when climbing, balancing rise against tread depth.
Why must all steps be the same height?
People build a walking rhythm from the first steps, so an uneven final step is a common cause of falls. That's why the rise is derived by dividing the total height into equal risers, never left as a leftover.