What a granny flat
costs in Perth.
A granny flat in Perth costs from $217,500 to build for the design alone on The Property Plug panel. Add real per suburb siteworks of about $20,636 to $37,107, and the home plus siteworks figure runs from roughly $238,136 to $343,107. Land is separate.
Last updated June 2026. Prices are indicative, exclude land, and are confirmed against your block before contract.
A real granny flat price is three figures, not one: the design base price, the siteworks for your block, and the land. Most quotes show only the design. The Property Plug shows the design plus real per suburb siteworks, so the build cost you see is the build cost you pay.
| Cost line | Typical range | What it covers |
|---|---|---|
| Design base price | $217,500 to $306,000 | The fixed-price build and inclusions for the chosen design |
| Siteworks | $20,636 to $37,107 | Earthworks, drainage, retaining and connections for your block |
| Home plus siteworks | $238,136 to $343,107 | The landed build cost, land excluded |
| Land | Varies by suburb | Purchased separately, or already owned for a backyard build |
For a backyard granny flat on a block you already own, the land line is effectively zero, which is exactly why the numbers work so well. You are adding a depreciable building to land you already hold.
IndicativeEstimate only, not a quote or an offer. Figures combine a home design starting price with the suburb siteworks and do not include land. Designs, builders, land and pricing change and are subject to availability. We confirm a fixed price with your matched builder on enquiry.
The same granny flat design lands at a different total in each suburb because siteworks differ block to block. Below is the Haven design, the most affordable on our panel, priced against real siteworks in five Perth corridors.
| Suburb | Design base | Siteworks | Home plus siteworks |
|---|---|---|---|
| Baldivis | $217,500 | $20,768 | $238,268 |
| Wellard | $217,500 | $20,916 | $238,416 |
| Alkimos | $217,500 | $26,822 | $244,322 |
| Byford | $217,500 | $30,201 | $247,701 |
| Gosnells | $217,500 | $25,218 | $242,718 |
We hold real siteworks for 102 Perth suburbs, so we can price any design against your exact corridor. See the full per suburb picture from any house and land hub.
- Fixed-price build contract for the chosen design
- Standard builder inclusions and fittings
- Structural works to the slab and frame
- Self contained kitchen, bathroom and living
- Siteworks for your specific block
- The land itself, unless building in your backyard
- Stamp duty and any finance or holding costs
- Upgrades beyond the standard inclusions
Allow around 8 months from contract to handover for the build itself, after design, approvals and siteworks. The WA ancillary dwelling rules page covers the 70m2 limit and permits that sit ahead of the build.
All 8 granny flat designs, cheapest build first. Open any design for full specs and a per suburb price.
How much does a granny flat cost to build in Perth?
On The Property Plug panel a granny flat build starts from $217,500 for the design alone. Add real per suburb siteworks of around $20,636 to $37,107, and the home plus siteworks figure runs from about $238,136 to $343,107. Land is purchased separately.
What is included in a granny flat price?
A base build price covers the design and the builder fixed-price inclusions. It does not include siteworks, which prepare the block, or the land itself. Our figures separate the design base price from real per suburb siteworks so you see the landed build cost, not a teaser.
Why do granny flat prices change by suburb?
Siteworks vary by block and suburb, covering earthworks, drainage, retaining and connections. Across Perth our siteworks data ranges from about $20,636 to $37,107, so the same design can land at different totals depending on where you build.
Is a granny flat cheaper than a full home?
Yes. With less floor area and almost no extra land cost on a block you already own, a granny flat from $217,500 build is a fraction of a full new home. That low cost on a high rent is what drives the dual income return.
Get a real granny flat price for your block
One request matches the full price list, your matched builder, and a siteworks figure for your exact suburb. Free to you.