Stairs Calculator
Calculate stair rise, going, step count and stringer length for AU residential stairs.
Estimate only — not a substitute for a licensed tradesperson, a certified engineer, or sign-off from your local building surveyor. Verify against current standards and site conditions before ordering materials or starting work.
Result
- Number of risers
- 15
- Actual riser height (kept within 115-190mm)
- 180mm
- Number of goings
- 14
- Going used in calculation
- 250mm
- Total going (horizontal run)
- 3,500mm
- Stringer length
- 4,420.41mm
NCC Housing Provisions Table 11.2.2a (verified 2026-08-20 against both the NCC 2022 and NCC 2025 editions on ncc.abcb.gov.au - identical figures in both). NCC 2022 remains the legally operative edition in most states/territories until each jurisdiction adopts NCC 2025 on its own timeline (e.g. NSW and QLD both adopt 1 May 2027) - confirm which edition currently applies where you're building, and check for any state-specific variation, before relying on this.
What this is based on
NCC Housing Provisions · Table 11.2.2a
Sets the permitted riser and going dimensions for stairs other than spiral, and the 2R+G slope relationship, for Class 1a (private/domestic) stairways.
Checked against NCC 2022 and NCC 2025 on 2026-08-20 — figures identical in both, so this applies whichever edition your state is under.
Figures verified directly from Table 11.2.2a: riser 115-190mm, going 240-355mm, 2R+G 550-700mm (stairs other than spiral). Spiral stairs have their own row, and Table 11.2.2b sets different dimensions for stairways serving non-habitable rooms used infrequently - this calculator covers neither. Always confirm state-specific variations with your certifier.
NCC Housing Provisions · Part 11.2.2(1)(a)
Limits a single flight to not more than 18 and not fewer than 2 risers.
Checked against NCC 2022 and NCC 2025 on 2026-08-20 — figures identical in both, so this applies whichever edition your state is under.
NSW is currently under NCC 2022. Adoption dates differ by state and territory — check yours before relying on any figure.
We cite the clause and link to the publisher so you can read the source yourself. We do not reproduce the text or tables of the NCC or of any Australian Standard.