Need Help With Water Ingress or Building Repairs?
If you're experiencing:
- Roof leaks
- Water ingress
- Rot or moisture damage
- Insurance-related repairs
- Mould or dampness issues
Aries Builders can assist with Emergency, Investigation, Reporting, Drying, Repairs, and Reinstatement works throughout Auckland.,
Straight Flight Stairs Calculator
Calculate riser and tread geometry for a straight stair flight — with automatic NZ Building Code compliance checking against NZBC D1 and NZS 3604.
How it works
1 Total rise
The vertical height from finished floor to finished floor, in millimetres.
2 Total run
The approximate horizontal space available for the stair. Used to confirm the layout fits.
3 Tread depth
The depth of one tread in mm. NZ minimum is 250 mm for private stairs.
4 Target riser
Your preferred riser height. The calculator rounds to the nearest whole number of risers and divides evenly. NZ maximum is 190 mm.
5 2R + T formula
The standard comfort check: twice the riser plus the tread should fall between 550–700 mm. This is what designers and building inspectors use.
6 Cumulative rise
Shows the exact height at each step — useful for setting out stringers and marking up on site.
Disclaimer
This calculator is for informational purposes only. While we strive for accuracy, the results provided should not be used as the sole basis for your construction decisions. Always consult a professional builder or engineer to ensure compliance with local building codes and regulations. Aries Builders is not responsible for any errors or discrepancies in the calculations.
Stair dimensions
