Guide
How much does a granny flat cost in Sydney?
Where the money goes
| 60 m², mid-range, level block | Low | High |
|---|---|---|
| Construction (60 m² × $2,400–3,000/m²) | $144,000 | $180,000 |
| Site works and separate services | $25,000 | $55,000 |
| Deck and landscaping | $17,000 | $45,000 |
| Design, survey, approvals and statutory charges | $12,968 | $42,138 |
| Contingency (10–15%) | $19,897 | $48,321 |
| Total project | $218,864 | $370,458 |
Four typical projects
| Project | Indicative total |
|---|---|
| Budget two-bed, level block The Doris, 54 m², detached, budget finish | $175k – $307k |
| Mid-range 60 m², level block Detached, mid-range finish, deck and landscaping | $219k – $370k |
| Mid-range 60 m², sloping block As above on a slope with reactive clay | $246k – $420k |
| Over a garage, premium Upper-level flat with garage below, premium finish | $377k – $611k |
Run your own numbers in the cost estimator.
Build rates per square metre
For a detached granny flat we use $2,000–$2,400/m² for a budget finish, $2,400–$3,000/m² mid-range and $3,000–$3,600/m² premium. Those rates cover the building only — slab to roof, fitted out — which is why a “from” price from a builder is never the project cost.
What design and approval cost
With Flat Grannys the design side is fixed: $450 + GST for a CDC approval set, $350 + GST to place it on your site survey (the survey itself is by others, typically $1,500–$3,500), and $1,800 + GST for the construction set. The certifier, BASIX, engineer, Long Service Levy and any council contributions are paid to others — see the fees page for typical amounts.
The costs people miss
- Services to the back of the block. Sewer, water and power runs plus separate meters are often $15–30k.
- Slope and soil. A sloping block or difficult access roughly doubles site works; reactive clay adds $80–140/m² to the slab.
- Council contributions. Some councils charge nothing for a granny flat; others charge up to about $20k.
- Two storeys. A flat over a garage adds the garage level, a stair and heavier engineering.
Is it worth it?
Sydney rental vacancy was 1.6% in June 2026 (SQM Research). A granny flat renting at $550 a week earns about $28,600 a year before costs — the estimator shows the gross yield for your numbers.
Indicative only — not a quote. Rates are aligned with the PlanLand cost estimator and reviewed quarterly.
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.