New Zealand · Free cost calculator
Get an online estimate
You’re estimating a Extension / addition. Answer the questions below to see an indicative planning range on screen.
Extension / addition · estimate
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Your addition is mostly:
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Free
No cost, no obligation
Indicative
A planning range, not a quote
Private
Your project is not broadcast
Estimate methodology
A planning model, not a quote.
Bracen's rule-based model starts with a project-type baseline, then applies the scope, approximate size, finish level and New Zealand region supplied in your answers. The displayed range is 10 percent either side of the calculated midpoint. A budget you enter is compared separately and does not set the result.
Site access, ground conditions, design detail, engineering, council requirements, selections, exclusions and market availability can move a real price materially. The model was last reviewed in September 2026 and is maintained as Bracen editorial guidance, not an official price index or quantity-surveyor assessment.
For wider assumptions and regional context, read the New Zealand cost-to-build guide.