About this calculator
Lay out a straight flight: the number of risers, exact riser height, total run, angle and stringer length, checked against the NCC rules for stairs in houses.
How it’s calculated
Risers = ceil(total rise ÷ maximum riser). Exact riser = total rise ÷ risers. Treads = risers − 1. Run = treads × tread depth. Stringer ≈ √(rise² + (run + one tread)²).
NCC Housing Provisions: riser 115–190 mm, going 240–355 mm, 2R + G between 550 and 700 mm, and 2 to 18 risers per flight. Open risers must not let a 125 mm sphere through.
Worked example
With these inputs:
- Total rise (floor to floor)
- 2600 mm
- Maximum riser height
- 190 mm
- Tread depth (going)
- 250 mm
- Nosing overhang
- 20 mm
- Stair width
- 900 mm
the result is:
- Risers
- 14 risers @ 186 mm
- Total run (going)
- 3.25 m
- Stair angle
- 36.6°
- Stringer length (approx.)
- 4.36 m
- 2R + G
- 621 mm
Tips from the trade
- Measure the total rise to the finished floor at both ends, not to the subfloor.
- Treat this as a layout check. Local code and the inspector have the final say.
- For stairs wider than 900 mm, add a middle stringer.
Common questions
How many steps for a 2.6 m rise?
2600 mm ÷ 190 mm = 13.7, so 14 risers at 185.7 mm. With 250 mm goings, 2R + G = 621 mm, inside the 550–700 mm range.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and the NCC and Australian Standards before ordering.