Before any wood is cut, every staircase comes down to a handful of measurements: how tall each step is (rise), how deep it is (run), how steep the overall pitch sits, and how much clearance you have overhead. Get these right and the stair feels effortless; get them wrong and people trip on it daily.
1. Measure the total rise
The total rise is the finished-floor-to-finished-floor vertical distance. Include flooring on both levels — a 5 mm tile difference at the top changes every step below it. For a typical residential floor-to-floor of 2,800 mm, that 2,800 mm is your total rise.
2. Solve for the number of risers
Most codes cap individual riser height at 190–200 mm for residential stairs. Divide total rise by your target riser height and round up:
risers = ceil(total_rise / target_riser_height) risers = ceil(2800 / 180) = 16
Then divide back to get the actual riser height: 2,800 ÷ 16 = 175 mm per riser. Every riser must be identical — variation greater than ~5 mm is a trip hazard and a code failure.
3. Pick the tread (run) depth
Treads are usually 240–280 mm deep for residential stairs. A common comfort formula is 2 × rise + run ≈ 600–640 mm. With our 175 mm riser:
run = 620 - (2 × 175) = 270 mm
Number of treads is always one fewer than the number of risers — the top landing counts as the last step. 16 risers means 15 treads.
4. Calculate the total run (length)
total_run = treads × run total_run = 15 × 270 = 4,050 mm
That is the horizontal floor space the staircase will occupy. If you don't have 4 m of clear floor run, you'll need a landing and a turn (L-shape or U-shape) to fit the same vertical climb in less length.
5. Check the pitch
Pitch is the angle of the stair from horizontal. Residential stairs are most comfortable between 30° and 37°. Calculate it as:
pitch = atan(rise / run) pitch = atan(175 / 270) ≈ 32.9°
6. Verify headroom
From the nosing of any tread, measure straight up to the nearest ceiling, beam or floor opening above. Minimum residential headroom is typically 2,000 mm (2 m). When a stairwell opening is too short, either lengthen the opening or split the climb with a landing.
Quick reference — typical residential limits
- Riser height: 150–200 mm (175 mm is the sweet spot)
- Tread depth: 240–280 mm
- 2 × rise + run: 600–640 mm
- Pitch: 30°–37°
- Headroom: ≥ 2,000 mm
- Handrail height: 900–1,000 mm above the nosing
- Stair width: ≥ 900 mm for primary stairs
Local codes vary — always confirm against the regulations in your jurisdiction before construction.
Want us to run the numbers for you?
Send us your floor-to-floor height and available run, and we'll come back with a code-compliant layout and a quote.