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Made in NZ · For NZ buildersStair calculator to NZBC D1/AS1
Riser, going, pitch, landings and headroom to NZBC D1/AS1 — then priced into the build, not worked out twice.
No credit card · Cancel anytime · Works offline on site · Flat NZD pricing
Stairs that pass D1/AS1
A timber stair has to fit the floor-to-floor height and still meet NZBC D1/AS1. For a main private stair, Table 6 sets a maximum riser of 190 mm, a minimum going of 280 mm and a maximum pitch of 37°; Table 7 limits one flight to 4.0 m of rise between landings (2.5 m on a common stair); and Table 1 needs 2 m of headroom above the pitch line. D1/AS1 has no minimum riser, no 2R+G rule and no minimum width for a stair inside a home — it calls 850 mm the practical minimum (900 mm on a common stair). Divide the total rise by the maximum riser, round up to whole equal risers, and check it all lands inside those limits.
Toolie works the riser and going split out for the floor-to-floor height, checks it against D1/AS1 Tables 6 and 7, works out the minimum stairwell opening for 2 m headroom and checks tread thickness and the notch/throat left in the stringer. It does not size the stringer (use BRANZ BU625 Table 3) and it does not draw the stair; the deck quote’s plan set includes a stair detail, and a deck quote prices the stair build off a real NZ pricebook.
- Equal risers from the floor-to-floor height
- Riser, going, pitch and landings checked to D1/AS1 Tables 6 + 7
- Minimum stairwell opening for 2 m headroom, tread thickness, notch and throat checks
- Stairs priced in a deck quote off a real NZ pricebook, with a stair detail in the plan set
- Works offline on site
It’s part of the quote, not a separate tool
In Toolie this isn’t a one-off calculator — it feeds the actual priced quote and the build programme. Describe the job or drop in a PDF plan and Toolie runs the take-off, applies NZ site intelligence and prices it off a real NZ pricebook.
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Common questions
What are the NZBC D1/AS1 limits for a private stair?
For a main private stair D1/AS1 Table 6 allows a riser up to 190 mm, a going of at least 280 mm and a pitch up to 37 degrees; Table 7 allows up to 4.0 m of rise between landings (2.5 m on a common stair); and Table 1 needs 2 m of headroom above the pitch line. There is no minimum riser, no 2R+G rule and no minimum width for a stair inside a home (850 mm is the practical minimum D1/AS1 suggests). Toolie checks your stair against these.
How do I work out the risers?
Divide the floor-to-floor height by the maximum riser for the stair type and round up to a whole number of equal risers, then check the going and pitch. Toolie does this for you and shows the next two riser counts.
Does it draw the stair?
The calculator itself does not draw. A deck quote's plan set includes a stair detail, and the stair is priced off a real NZ pricebook. It does not size the stringers; use BRANZ BU625.
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