Cost estimator
What a granny flat really costs
A builder’s price covers the building. The project also needs site works, services, approvals and council charges. Enter your lot and pick a design — the estimator shows which approval pathway applies and prices the whole project.
Indicative only — a guide to budgeting, not a quote or a cost estimate for finance or contract purposes. Construction rates include GST as published by their sources; Flat Grannys and PlanLand fees are shown ex GST. Council and certifier charges vary by council and are indexed annually. Rates are aligned with the PlanLand cost estimator.
Why the price per square metre isn’t the price
Builders quote a rate per square metre for the building itself. A granny flat project also needs the ground prepared, sewer, water and power run to the back of the block, separate meters, a deck, the survey, engineer, BASIX, the certifier and council charges — and a contingency for what the ground turns out to be.
On a typical 60 m² flat those items add a third or more to the builder’s number. The estimator shows each one so nothing surprises you after approval.
See the full breakdown in our granny flat cost guide for Sydney.
Can you build a granny flat on your block?
Send us the address. We check it against the NSW controls and tell you what fits, which pathway applies and what it will cost — free, within one business day.