Can a builder charge more than the quote in NZ?
Short answer
It depends whether you have a fixed-price contract or a charge-up (cost-reactive) arrangement. A genuine fixed-price quote shouldn't change unless you approve a variation or the scope changes. Estimates and charge-up jobs can move with the actual labour and materials used. Always get the pricing basis in writing before work starts.
Key facts
- Fixed price: shouldn't change without an agreed variation
- Charge-up / estimate: can move with actual costs
- Variations must be agreed — ideally in writing — before the work
- Get the pricing basis in writing before you start
Quote vs estimate vs charge-up
A 'quote' usually implies a fixed price for a defined scope. An 'estimate' is an educated guess that can change. A 'charge-up' (or cost-reactive) job is billed on actual labour and materials, so the final figure isn't locked in. These mean very different things for your budget.
Variations — the usual culprit
Most price increases on fixed-price jobs come from variations — changes to the scope, or things found once work starts (especially in older homes). A good builder prices and gets sign-off on variations before doing them, not after.
Protect yourself
Make sure your contract states whether the price is fixed or charge-up, and sets out a clear variations process. For work of $30,000 or more this should be in your written contract.
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Sources: MBIE / Building Performance — residential building contracts. General information for NZ homeowners, not legal advice — building rules change and vary by council, so confirm critical details on the official source before acting. Last updated 2026-05.