Stair Calculator Australia — Rise, Going & NCC ComplianceNCC
Stair dimensions
Measure vertically from finished floor level to finished floor level.
NCC minimum: 240 mm · Comfortable residential: 270–320 mm
NCC minimum for a private stair: 600 mm · Comfortable: 900–1000 mm
Typical: 19 mm (DAR pine), 32 mm (hardwood), 42 mm (feature hardwood)
Stair layout
Dimensions per step
Overall stair geometry
Timber required
✓ NCC Compliant
⚠ NCC Issues Found
This Australian stair calculator works out the number of risers, actual riser height, going (tread depth), total run, stringer length, and pitch angle for any staircase. It performs a live NCC (National Construction Code) compliance check against the key dimensional limits for private residential stairs: maximum riser height 190 mm, minimum going 240 mm, minimum stair width 600 mm, and the 2R+G comfort formula (target range 550–700 mm). The calculator divides your total rise evenly across the minimum number of steps required to stay within the 190 mm riser limit, then reports the actual riser height and flags any non-compliance clearly.
Frequently Asked Questions
What is the maximum riser height for stairs in Australia under the NCC?
The National Construction Code (NCC) Volume 2, Part 3.9.1 sets the maximum riser height for a private stairway (in a house) at 190 mm. The minimum riser height is 115 mm. These limits apply to all habitable building work in Australia. Commercial stairs (NCC Volume 1) follow similar but slightly different limits under AS 1657.
What is the minimum going (tread depth) for stairs in Australia?
The NCC specifies a minimum going of 240 mm for private residential stairs. The going is measured horizontally from the front edge (nosing) of one tread to the front edge of the next. A going of 270–300 mm is considered comfortable for most adults. Shallower goings force you to descend side-on and increase the risk of falls.
What is the 2R+G stair comfort formula?
The 2R+G formula — where R is the riser height and G is the going in millimetres — is an ergonomic guideline for comfortable stair proportions. A result between 550 mm and 700 mm is considered comfortable, with 600–650 mm being ideal. This formula originated in 17th-century French stair design and is widely referenced by Australian stair builders, although the NCC does not mandate a specific 2R+G value.
How do I measure total rise for a staircase?
Total rise is the vertical distance from finished floor level at the bottom of the stairs to finished floor level at the top. Measure this after floor finishes (tiles, floorboards, carpet) are in place, or calculate finished heights from your structural drawings. Getting this measurement wrong by even 5–10 mm results in inconsistent riser heights, which is a tripping hazard and an NCC non-compliance.
Do stairs require a handrail in Australia?
Under NCC Volume 2, a handrail is required on any stairway with 2 or more risers in a residential building. The handrail must be between 865 mm and 1000 mm above the nosing of each tread, and must be continuous from the top to the bottom riser. Balustrades are required where the floor level is more than 1 m above ground or the floor below.