A 60 m² two-bedroom granny flat in Perth costs about $158,000–$237,000 all-in, built by a builder. That is roughly $3,290 per m², including GST, design, building permit, connections and basic landscaping on an easy block.
All-in, built by a builder, on an easy flat block. Includes GST, design, permits, connections and basic landscaping.
| Size | Budget | Standard | Premium |
|---|---|---|---|
| Studio, 30 m² | $89,000– | $98,000– | $115,000– |
| 1 bedroom, 45 m² | $116,000– | $129,000– | $153,000– |
| 2 bedrooms, 60 m² | $141,000– | $158,000– | $188,000– |
| 3 bedrooms, 70 m² | $158,000– | $177,000– | $211,000– |
The block matters more than the design. Add these on top of the table:
| Site issue | Adds about |
|---|---|
| Sloping block, more than about 1 m fall | $10,000–$35,000 |
| Sewer uphill or far away (pump needed) | $8,000–$16,000 |
| Tight side access (crane or hand work) | $5,000–$11,000 |
| Old shed or garage to remove | $4,000–$14,000 |
| Reactive clay soil (deeper footings) | $12,000–$25,000 |
| Second bathroom | $18,000–$28,000 |
About $158,000–$237,000 all-in for a standard finish on an easy block, or about $3,290 per m².
About $177,000–$262,000 all-in with a standard finish. 70 m² is the most WA allows without planning approval.
Not if it is 70 m² or less, on residential land and meets the R-Codes. You still need a building permit.
A new junction, long runs to the main or a sewer that sits uphill all add cost. Connections alone often run $7,500 to $19,000.
Yes, if you manage the trades: about $119,000–$185,000 all-in for 60 m², against $158,000–$237,000 turnkey.
Put this price and your expected rent into the rent and ROI calculator to see the yield and payback time.
Prices are all-in estimates including GST, from our cost calculator, which is built on 2026 builder price lists and cost guides. Checked 25 October 2026. Get at least two quotes after a site visit.