Build a complete budget
Project costs can be affected by design complexity, site access, soil and services, demolition, permits, approvals, finishes and landscaping. Ask every provider what is included and excluded in writing.
Compare like with like
When comparing quotes, line up floor area, specification, site works, permits, utility connections, timelines and provisional sums. A lower headline figure may not represent the final project cost.
Typical cost ranges (Melbourne, 2026)
These are indicative ranges only. Actual costs vary widely by site, specification, and provider. Always get written quotes for your specific situation.
- Studio / one-room granny flat: $80,000 – $150,000
- One-bedroom granny flat: $120,000 – $220,000
- Two-bedroom granny flat: $180,000 – $350,000
- Secondary dwelling (full home): $250,000 – $500,000+
Key cost factors
- Site access and preparation: Excavation, retaining walls, and access for machinery can add $10,000–$50,000+.
- Soil conditions: Poor soil may require additional foundations, adding $5,000–$20,000.
- Services connection: Connecting to water, sewer, power, and internet can cost $5,000–$15,000.
- Permits and approvals: Building and planning permits typically cost $1,000–$5,000 depending on complexity.
- Finishes: Upgrading kitchens, bathrooms, and flooring can add $10,000–$40,000.
This guide provides general information only. Costs vary by property, council, and provider. Always obtain written quotes and verify current pricing before making decisions.