How Much Does a Granny Flat Cost in Australia in 2026
A granny flat is the cheapest way to add a second dwelling to a block you already own — no land purchase, no stamp duty, no subdivision. That's why backyards from Blacktown to Broadmeadows are filling up with them.
The catch is that "granny flat cost" means three different numbers depending on who's quoting: the base build, the turnkey price, and the number you actually pay once the slab, the services and the council are done with you. Builders advertise the first one. You pay the third.
This guide separates all three. It covers granny flat price per square metre, two bedroom granny flat cost, state-by-state approval rules, and the site costs that almost never appear in an advertised price. If you want a ballpark before you ring a single builder, run your numbers through Leadkit's builder and renovation quote calculator first.
Last updated: August 2026
Key takeaways
- A granny flat costs $95,000–$300,000 turnkey in Australia in 2026, or roughly $2,300–$3,500 per square metre for a site-built secondary dwelling.
- A two bedroom granny flat (50–60 m²) costs $140,000–$210,000 turnkey in most metro areas, and $180,000–$260,000 in Sydney where site costs and trade rates are highest.
- Granny flats cost more per m² than a full house because one kitchen, one bathroom and a full set of service connections are spread across 60 m² instead of 200 m².
- Site costs are the budget killer: slab and site prep ($6,500–$25,000), water and sewer connection ($5,000–$10,000), electrical supply and metering ($3,000–$7,000) and council approval ($3,000–$5,500) are usually excluded from a "base build" price.
- NSW caps a secondary dwelling at 60 m² internal on a lot of at least 450 m², and a Complying Development Certificate can be approved in as little as 20 days instead of a months-long DA.
- The cheapest lever is keeping the build under the state size cap, on flat ground, close to the existing sewer line. The most expensive one is a sloping block with no truck access.
This is a price indication only. Your tradie will confirm the final price after assessing the job.
Table of contents
- How much does a granny flat cost in Australia in 2026?
- What is the granny flat price per square metre?
- How much does a two bedroom granny flat cost?
- What is the granny flat build cost in NSW?
- How much does a granny flat cost in each city?
- What site costs are excluded from a turnkey price?
- What does council approval cost, and do you need a DA or a CDC?
- What drives secondary dwelling cost up or down?
- Is a granny flat worth it financially?
- How to compare granny flat quotes properly
- FAQ
- Get a granny flat estimate now
How much does a granny flat cost in Australia in 2026?
A granny flat costs $95,000–$300,000 in Australia in 2026 for a turnkey, site-built secondary dwelling, with most two-bedroom builds landing between $140,000 and $210,000. Studio conversions of an existing garage start lower; three-bedroom builds on difficult sites go higher.
| Granny flat type | Typical size | Turnkey cost (inc. GST) | Cost per m² |
|---|---|---|---|
| Garage or shed conversion | 30–50 m² | $60,000–$130,000 | $1,800–$2,800 |
| Studio / one-bedroom, site-built | 35–45 m² | $95,000–$150,000 | $2,700–$3,400 |
| Two-bedroom, modular or prefab | 50–60 m² | $120,000–$180,000 | $2,200–$3,000 |
| Two-bedroom, site-built | 50–60 m² | $140,000–$210,000 | $2,600–$3,500 |
| Three-bedroom (where the state cap allows) | 60–90 m² | $180,000–$300,000 | $2,800–$3,600 |
| Attached secondary dwelling / extension-style | 50–60 m² | $180,000–$260,000 | $3,300–$4,300 |
| Second-storey addition over a garage | 45–60 m² | $200,000–$320,000 | $3,800–$5,000 |
This is a price indication only. Your tradie will confirm the final price after assessing the job.
Methodology note: these ranges are anchored to the default rates configured in Leadkit's builder and renovation quote calculator, cross-checked against advertised turnkey pricing from Australian granny flat builders. That calculator is Leadkit's own tool — not neutral third-party data — and it prices new floor area at a default of $4,000/m² for an attached extension and $3,200/m² for new project-home-standard construction, before finish tier, access and approval adjustments. A detached granny flat normally sits between those two figures per square metre.
Across the 202 calculators in Leadkit's library, 31 ask a site-access question before they'll produce a number, and 53 apply a minimum job fee. That's not a design quirk — it's what Australian pricing actually looks like. Access and fixed costs move small-build numbers more than the finishes do.
Want a ballpark in 60 seconds? Use the free builder and renovation quote tool — enter your floor area, finish tier and site access and you'll get an instant estimate. Results are an indication only; your builder confirms the final price after a site visit.
What is the granny flat price per square metre?
Granny flat price per square metre in Australia is $2,300–$3,500/m² for a standard site-built secondary dwelling in 2026, rising to $4,000–$5,000/m² for attached or second-storey work. Medium-spec brick veneer sits near the bottom of that band; high-spec finishes push toward the top.
That's noticeably dearer per metre than a new house, and homeowners are constantly caught out by it. A 200 m² project home might build at $2,000–$2,800/m². A 60 m² granny flat with the same finishes costs more per metre for one simple reason: fixed costs don't shrink with floor area.
A granny flat still needs:
- one kitchen, with the same cabinetry run, benchtop and appliance package
- one full bathroom, with waterproofing, tiling and fixtures
- one hot water unit, one switchboard, one meter
- one set of water, sewer and electrical connections back to the street or the main house
- one slab, one roof, one full set of external walls
Spread $85,000 of that fixed content over 60 m² and it's $1,400/m² before a single square metre of "living area" is built. Spread it over 200 m² and it's $425/m².
The practical consequence: the per-metre rate falls as the build gets bigger. A 35 m² studio often runs $3,200–$3,400/m² while a 90 m² three-bedroom lands at $2,800–$3,000/m². If you're weighing 50 m² against 60 m², the extra 10 m² is usually the cheapest floor space you'll ever buy — you're only paying for slab, frame, roof and lining, not another kitchen.
How much does a two bedroom granny flat cost?
A two bedroom granny flat costs $140,000–$210,000 turnkey in most Australian metro areas in 2026, based on a 50–60 m² site-built design. In Sydney, where trade rates and site costs run hardest, the same build typically lands at $180,000–$260,000.
Here's how a 60 m² two-bedroom build usually splits up:
| Line item | Typical share | Indicative cost |
|---|---|---|
| Base build (frame, roof, lining, windows, doors) | 45–55% | $70,000–$105,000 |
| Kitchen and bathroom (supply and install) | 12–18% | $20,000–$35,000 |
| Slab and site preparation | 6–12% | $9,000–$25,000 |
| Services — water, sewer, electrical, gas | 6–10% | $9,000–$18,000 |
| Design, engineering, certification and council | 5–8% | $8,000–$16,000 |
| Driveway, paths, fencing and landscaping | 4–10% | $6,000–$20,000 |
| Builder's margin and project management | 12–18% | included above |
This is a price indication only. Your tradie will confirm the final price after assessing the job.
The two-bedroom format dominates the market because it's the sweet spot: it fits inside the 60 m² cap that applies in NSW and Victoria, it rents to a couple or a small family rather than a single tenant, and it doesn't need a second bathroom.
One thing worth knowing before you brief a builder: the second bedroom itself is cheap. Adding a 9 m² bedroom to a one-bedroom design typically adds $22,000–$32,000 — mostly slab, frame, roof and lining. It's the bathroom, not the bedroom, that carries the cost.
What is the granny flat build cost in NSW?
Granny flat build cost in NSW runs $150,000–$260,000 turnkey for a two-bedroom 60 m² secondary dwelling in 2026, with Western Sydney builds typically quoted at $180,000–$260,000. NSW is the most mature granny flat market in the country — and also the most tightly specified.
Under the NSW Housing SEPP administered by the Department of Planning, a secondary dwelling in NSW must generally meet these rules:
- maximum 60 m² internal floor area (unless the local planning instrument allows more)
- minimum lot size 450 m²
- minimum lot width 12 m at the building line
- maximum building height 8.5 m
- 3 m minimum rear setback, and 0.9 m side setback under 4.5 m in height
- only one secondary dwelling per lot, on the same title as the principal dwelling
NSW also allows you to rent a granny flat to anyone — not just family — which is why it's treated as an investment product there in a way it isn't in some other states.
Two NSW-specific costs to budget for:
Home Building Compensation Fund (HBCF) cover. Any residential building work over $20,000 in NSW requires the builder to take out HBCF insurance, and the premium is passed on to you. Check the builder's licence and insurance status through NSW Fair Trading before you sign anything — an unlicensed "builder" quoting $30,000 under the going rate is not a bargain.
BASIX certificate. NSW requires a BASIX certificate — the sustainability assessment covering water, thermal comfort and energy — for a new secondary dwelling. Budget $300–$600, and expect it to dictate your glazing spec and hot water system rather than the other way around.
The other states are meaningfully different:
- Victoria allows a small second dwelling up to 60 m² without a planning permit on most lots of 300 m² or more, though a building permit is still mandatory. It can be rented but not subdivided or sold separately. See Planning Victoria for the current provisions.
- Queensland calls it a secondary dwelling; the old family-only occupancy restriction was removed in 2022, so it can generally be rented to anyone subject to council approval.
- Western Australia allows ancillary dwellings up to 70 m² on most residential lots without a planning permit under the R-Codes, with no minimum lot size. A building permit is always required.
- South Australia and Tasmania treat them as ancillary accommodation with council-specific conditions — check with the council before you commission drawings.
How much does a granny flat cost in each city?
Granny flat costs vary by roughly 40% between the cheapest and dearest Australian capitals, driven almost entirely by trade labour rates and council charges rather than materials. Materials are broadly national; labour is not.
| City | Two-bedroom 60 m² turnkey | Notes |
|---|---|---|
| Sydney | $180,000–$260,000 | Highest trade rates; tight blocks, frequent access premiums |
| Melbourne | $160,000–$260,000 | Strong builder competition since the small second dwelling reforms |
| Brisbane | $130,000–$200,000 | Timber-frame on stumps common; cyclone-region spec adds cost north of the city |
| Perth | $120,000–$190,000 | Double-brick standard; ancillary dwellings up to 70 m² permitted |
| Adelaide | $120,000–$180,000 | Lowest metro labour rates of the mainland capitals |
| Gold Coast | $140,000–$220,000 | Site access and soil classification drive the spread |
| Regional NSW / VIC / QLD | Add 10–20% | Travel, accommodation and thinner trade availability |
This is a price indication only. Your tradie will confirm the final price after assessing the job.
The regional premium surprises people who assume country building is cheaper. It isn't, for a 60 m² job. A builder two hours from the depot is pricing travel time for every trade that visits — and a granny flat needs a plumber, an electrician, a concreter, a framer, a roofer, a plasterer, a tiler and a painter to each make several trips.
What site costs are excluded from a turnkey price?
Site costs — slab, excavation, service connections, drainage and driveway — typically add $25,000–$60,000 to an advertised granny flat "base price", and they're the single biggest source of budget blowout in Australia. Advertised prices assume a flat, cleared, easy-access block with services at the boundary. Very few blocks are that.
The slab
A granny flat sits on either a waffle pod slab, a conventional raft slab, or timber bearers on stumps. For a 60 m² engineered slab, working from the default rates in Leadkit's concrete slab cost calculator — $300/m³ for concrete supply and place, $35 per lineal metre of formwork, $45/m³ for excavation and a $600 pump fee — a 6 m × 10 m slab at 150 mm works out to roughly $6,500–$9,000 on flat, cleared ground.
Add a sloping site and that changes fast. Cut-and-fill, retaining and a drop-edge beam can double it. Reactive clay soils (an H1 or H2 site classification) mean a deeper, more heavily reinforced slab again.
Services
| Site cost item | Indicative cost | What triggers it |
|---|---|---|
| Site clearing, tree removal, levelling | $3,000–$15,000 | Trees, sheds, old paving in the build zone |
| Excavation and cut-and-fill | $5,000–$25,000 | Slope over about 1 m across the pad |
| Slab (60 m², engineered) | $6,500–$9,000 | Standard on flat, cleared ground |
| Water and sewer connection | $5,000–$10,000 | Distance to the point of connection; sewer depth |
| Sewer junction / boundary trap | $2,500–$6,000 | Where no existing junction is available |
| Electrical supply, trenching and metering | $3,000–$7,000 | Separate meter, underground run from the switchboard |
| Stormwater and drainage | $2,000–$8,000 | Council-required detention or absorption trench |
| Driveway, path and crossover | $5,000–$20,000 | Separate vehicle access to the secondary dwelling |
| Fencing and landscaping | $3,000–$15,000 | Privacy screening between dwellings |
This is a price indication only. Your tradie will confirm the final price after assessing the job.
Two terms worth knowing when you read a quote:
- Point of connection — where your new dwelling ties into the existing water, sewer or power infrastructure. The further it is, and the deeper the sewer, the more you pay. A granny flat 4 m from the existing sewer junction is a cheap connection; one 25 m away across a driveway is not.
- Provisional sum (PS) and prime cost (PC) items — allowances in the contract for work that hasn't been fully priced yet, like excavation or floor coverings. They're legitimate, but a quote stacked with them isn't really a fixed price. Ask how each allowance was calculated.
Electrical fitout is another line that quietly adds up. Using the default rates in Leadkit's electrical quote calculator — $180 per power point, $110 per downlight, $280 for a safety switch — a modest 60 m² fitout with 14 GPOs, 16 downlights and a new RCD-protected board runs about $5,000–$6,500 before the supply trenching.
What does council approval cost, and do you need a DA or a CDC?
Council approval for a granny flat costs $3,000–$5,500 in most of Australia once certification, lodgement and planning fees are counted, and takes anywhere from 20 days to five months depending on the pathway. There are two pathways, and the one you qualify for matters more to your timeline than to your budget.
Complying Development Certificate (CDC) — a fast-track approval issued by a private certifier or council when the design meets every rule in the relevant code. In NSW, a compliant secondary dwelling on a lot of 450 m² or more can be approved in as little as 20 days. This is the pathway most granny flat builders design to, and it's why standard designs are so standard.
Development Application (DA) — the full council assessment, needed when anything falls outside the code: heritage overlays, flood or bushfire zones, undersized or oddly-shaped lots, tree removal, or a design over the size cap. Expect three to five months, sometimes longer, and higher consultant costs.
Leadkit's builder renovation calculator carries a default council DA and approvals allowance of $5,500 for exactly this reason — it covers the application, the building permit and a planning consultant's time, and it's the figure most homeowners forget entirely.
Around it, budget for the professional documentation:
| Approval-related cost | Indicative cost |
|---|---|
| Site survey / contour and detail survey | $800–$2,500 |
| Building designer or draftsperson | $2,500–$6,000 |
| Architect (if engaged instead) | 5–15% of build cost |
| Engineering (slab and frame design) | $1,500–$3,500 |
| BASIX / energy rating certificate | $300–$600 |
| Soil / geotechnical test and classification | $600–$1,200 |
| Council or certifier lodgement fees | $1,500–$4,000 |
| Section 7.11 / 7.12 developer contributions (NSW, if applicable) | $0–$25,000 |
This is a price indication only. Your tradie will confirm the final price after assessing the job.
That last line is the one that catches investors. Some NSW councils levy local infrastructure contributions on a new secondary dwelling; many waive them entirely for granny flats. It's a five-figure swing that depends purely on your council, so ring them before you commit. If you're weighing up a designer versus an architect, our guide to architect fees in Australia breaks down what each percentage actually buys,, and our land survey cost guide covers what a contour and detail survey should run.
What drives secondary dwelling cost up or down?
Secondary dwelling cost is driven by five things in order of impact: site conditions, floor area, finish tier, access, and timeline. Everything else is noise.
Site conditions (up to +40%). Slope, soil classification, rock, tree roots and distance to services. A flat, sandy, cleared block with the sewer at the boundary is the cheapest granny flat site in the country. A clay block with a 1.5 m fall and a mature gum in the middle is the dearest.
Floor area (the biggest lever you control). Because the fixed content dominates, going from 50 m² to 60 m² usually adds far less per metre than the headline rate suggests. Going over the state cap, though, throws you out of the CDC pathway and into a DA — which costs months, not just money.
Finish tier (−15% to +100%). Leadkit's builder renovation calculator applies multipliers of 0.85 for builder's standard, 1.0 for mid-range, 1.4 for premium and 2.0 for luxury or architect-designed. On a $150,000 build that's a spread of roughly $127,000 to $300,000 for the same footprint. Stone benchtops, custom joinery and imported tapware are lovely; they are also where granny flat budgets go to die.
Site access (+10% to +30%). The calculator's default multipliers are 1.1 for tight access, 1.25 where no truck can get in, and 1.3 for lift-dependent sites. Backyard builds behind an existing house are the textbook tight-access job — every cubic metre of concrete gets pumped over the roof, and every sheet of plasterboard is carried down the side path by hand.
Timeline (+15% for urgent). Priority scheduling and overtime carry a default 15% premium. If you can give a builder a six-month window instead of a six-week one, you'll usually get a better price.
Operator note: across the quote calculators configured on Leadkit, the variables that builders and renovators most often adjust away from the defaults are site access and minimum job fee — a fair signal that access and small-job overheads are what Australian builders find hardest to price generically. Materials rates get edited far less often.
Is a granny flat worth it financially?
A granny flat typically adds more to a property's sale value than it costs to build, and returns 5–10% gross rental yield on the build cost in metro areas — but the numbers only work if your site costs stay contained. That's the whole argument in one sentence.
Run it properly:
- Build cost: $180,000 all-in for a two-bedroom in outer Sydney
- Rent: $480–$620/week in most outer-metro markets, or roughly $25,000–$32,000 a year gross
- Gross yield on build cost: about 14–18% — attractive, but before costs
- Net, after rates, insurance, maintenance, agent fees and vacancy: typically 8–12%
Then the offsets. Rental income from a granny flat on your principal residence is assessable income, and renting out part of your home can affect the capital gains tax exemption on that portion — talk to your accountant, and check the current rules with the Australian Taxation Office rather than a forum. Some councils also reassess rates when a second dwelling is added.
The non-financial case is often the stronger one anyway. Housing an ageing parent within sight of the back door, or an adult kid who can't crack the deposit, is worth more to most families than a percentage. The Housing Industry Association has tracked multigenerational living as one of the steadier drivers of residential building activity through the past few years, and granny flats are the least disruptive way to do it.
If you're comparing a granny flat against simply adding rooms to the main house, our house extension cost guide puts the two side by side — an extension usually costs more per square metre but avoids a second set of service connections.
How to compare granny flat quotes properly
Compare granny flat quotes on inclusions, not on the headline number — a $135,000 quote and a $185,000 quote for the same 60 m² build are usually pricing two completely different scopes. Get every quote onto the same footing before you compare a cent.
Ask every builder these eight questions in writing:
- Is this a base build or turnkey price? Turnkey should mean you can move furniture in. Confirm what "turnkey" excludes — it almost always excludes something.
- Are site costs fixed or provisional? If excavation and connections are PS items, the price isn't fixed.
- What soil classification is the slab priced on? A quote priced on class A sand is worthless on H2 clay.
- Is council approval, certification and engineering included?
- Are service connections included, and to what distance? Ask for the assumed metres of trenching.
- Is driveway, path, fencing and landscaping in or out? Usually out.
- What's the HBCF or state equivalent warranty insurance position? Check the licence number against the state regulator.
- What's the progress payment schedule, and what triggers each claim?
Then build a single comparison line: total cost, divided by internal floor area, with every exclusion listed underneath. That per-m² figure is the only honest way to compare a modular quote against a site-built one.
Before you brief three builders, get your own number. Run a builder and renovation quote estimate with your own floor area, finish tier and access — walking into a quote conversation with a defensible ballpark changes the conversation entirely. Results are an indication only; your builder confirms the final price after assessing the site.
FAQ
Q: How much does a granny flat cost in Australia in 2026?
A: A granny flat costs $95,000–$300,000 turnkey in Australia in 2026, with most two-bedroom 50–60 m² builds landing at $140,000–$210,000. Per square metre that's $2,300–$3,500 for a standard site-built secondary dwelling. Garage conversions start around $60,000; attached or second-storey additions run to $320,000. The single biggest variable is site cost — slab, excavation, service connections and driveway typically add $25,000–$60,000 on top of an advertised base build price. This is a price indication only. Your tradie will confirm the final price after assessing the job.
Q: How much does a two bedroom granny flat cost?
A: A two bedroom granny flat costs $140,000–$210,000 turnkey in most Australian metro markets, or $180,000–$260,000 in Sydney. That's for a 50–60 m² site-built design with one bathroom, a full kitchen, and standard mid-range finishes. Modular and prefab two-bedroom builds come in lower at $120,000–$180,000 but still carry the same site preparation and connection costs, which are quoted separately. Adding the second bedroom to a one-bedroom design usually only costs $22,000–$32,000 — it's the bathroom and kitchen that carry the money, not the bedrooms. You can size the job in about a minute with Leadkit's builder and renovation quote calculator.
Q: What is the granny flat price per square metre in Australia?
A: Granny flat price per square metre is $2,300–$3,500/m² for a standard site-built secondary dwelling in 2026, rising to $4,000–$5,000/m² for attached or second-storey work. That's higher per metre than a full house because the kitchen, bathroom, hot water unit, switchboard and service connections are fixed costs spread across a much smaller floor area. The rate drops as the build grows: a 35 m² studio often runs $3,200–$3,400/m² while a 90 m² build sits closer to $2,800–$3,000/m². This is a price indication only.
Q: Can you rent out a granny flat in Australia?
A: Yes, in most states you can now rent a granny flat to anyone, not just family. NSW has allowed this for years and treats secondary dwellings as a legitimate investment product. Queensland removed its family-only occupancy restriction in 2022, and Victoria's small second dwellings can be rented but not subdivided or sold separately. Expect $480–$620 a week for a two-bedroom in outer metro areas, which is a gross yield of roughly 14–18% on build cost before costs. Rental income is assessable, and renting part of your principal residence can affect your capital gains tax exemption — check with your accountant.
Q: How long does it take to build a granny flat?
A: A granny flat takes six to twelve months from first sketch to handover in 2026. Design and documentation runs four to eight weeks, approval takes 20 days by CDC or three to five months by DA, and construction itself is typically ten to sixteen weeks on a straightforward site. Modular builds compress the construction phase to four to eight weeks because the unit is built in a factory while the slab and connections are done on site, but the approval stage doesn't move. Sloping sites, wet weather and service connection delays are the three most common causes of overrun.
Q: Is a granny flat cheaper than an extension?
A: Usually yes, per square metre. A detached granny flat runs $2,300–$3,500/m² while an attached extension typically costs $3,300–$4,300/m², because tying new structure into an existing roof, wall and floor level is fiddly, disruptive work. Extensions do avoid a second set of service connections and a second slab, so on very small additions the gap narrows. The other difference is disruption: you can live normally through a backyard granny flat build, but living through an extension usually attracts a 15–20% premium for staged work and dust protection. The house extension cost guide compares them line by line.
Q: Does a granny flat add value to your property?
A: Generally yes — a well-built, compliant granny flat usually adds more to sale value than it cost to build, particularly in markets where rental demand is strong and lot sizes are large enough to keep the backyard usable. The value is driven by the rental income it can generate, so a legally approved dwelling with certificates is worth substantially more than an unapproved conversion, which can actively deter buyers and hold up a sale. Keep every approval, certificate and compliance document — they're part of the asset.
Q: What is the cheapest way to build a granny flat?
A: The cheapest granny flat is a modular or prefab two-bedroom on a flat, cleared block close to existing services, built to a standard design that qualifies for fast-track approval. That combination lands around $120,000–$180,000 plus site costs. Converting an existing garage is cheaper still at $60,000–$130,000, but only where the structure, slab and setbacks already comply — a slab that isn't rated or waterproofed for habitable use has to be replaced, which erases the saving. Avoid custom designs, sloping sites, and anything that pushes you into a full DA.
Get a granny flat estimate now
Granny flat cost in Australia comes down to three numbers: the build rate ($2,300–$3,500/m²), the site cost ($25,000–$60,000), and the approval pathway (20 days or five months). Get those three right and a two-bedroom secondary dwelling lands somewhere between $140,000 and $210,000 in most of the country.
Get them wrong — a sloping block, a distant sewer connection, a design 3 m² over the cap — and the same build costs $80,000 more and takes four months longer.
The fastest next step: browse Leadkit's free Australian cost calculators and run the builder and renovation tool with your floor area, finish tier, access and approval requirements. You'll have a defensible ballpark in under a minute — before you brief a single builder.
Are you a builder quoting granny flats? Embed a free Leadkit calculator on your own site in 60 seconds — every enquiry arrives with the floor area, finish tier and site details already filled in, so you're not chasing people for basics.
All prices in this guide are indicative only and include GST. Actual costs depend on your site conditions, soil classification, council, finish selection and your builder's own rates. This is a price indication only. Your tradie will confirm the final price after assessing the job.