cost data
Know what it costs
before you call anyone.
Melbourne builders will not quote you until you have drawings. Drawings cost money. So most people commit to a designer without any idea whether the project is a $200,000 job or a $600,000 one. That is the wrong way round.
Eight questions · No phone call · Full calculation shown
Not sure what you are allowed to build? Check the overlays on your address first — it takes a few seconds and fills in two of the questions.
Why this exists
Nobody publishes prices
The industry standard is "contact us for a quote." Homeowners spend months guessing, and the information asymmetry is not accidental.
We show the working
Every estimate breaks down line by line — the base rate, each site adjustment, professional fees, contingency. Including the parts that are our judgement rather than published data.
We tell you how we are paid
AE Index refers projects to a partner building company and earns a fee on work that proceeds. It is on the about page and in every report.
The order that saves money
Most people commission drawings, fall for them, and then discover a control they should have known about at the start. Both of these are free, and doing them in this order costs you nothing but saves the redesign.
What can you build?
Start typing your address. We will show the planning overlays and zone that apply, and what each one means for a renovation.
What will it cost?
An indicative range with every line of the calculation shown, plus a PDF report you can take to a builder. Arrive from step one and two questions are already answered.
Start an estimate →Costs by suburb
Eighteen Melbourne suburbs, each written separately. The differences between them are rarely what people expect.
Typical rear extension. Pre-1920 weatherboard, narrow blocks.
Brunswick 3056Typical rear extension. Solid brick, deep allotments.
Fitzroy 3065Typical rear extension — but only 30 m². Access is the cost.
Large period houses, extensive heritage.
Brighton 3186Biggest blocks. Salt drives specification.
Preston 3072Post-war brick veneer. Least expensive of the set.
Cost guides
The published basis
Square-metre rates come from the Archicentre Australia CostGuide 2026, an independently published Australian cost guide. Adjustments for location, site access, heritage overlay and building age are ours, and we label them as ours everywhere they appear. Read the full method on the Index.
Last updated 28 July 2026