How Much Does a Granny Flat Cost in NSW? (2026 Guide)
What a granny flat costs to build in NSW
Construction alone typically costs $2,000–$3,800 per square metre, set mostly by the finish level. A 60 m² granny flat at a mid-range finish costs about $144,000–$168,000 to build. Site works, approvals, council contributions and a 10–15% contingency take it to about $175,000–$230,000 on a flat block, before design, service connections and landscaping, which are priced for your site.
- $2,000–$3,800per m², construction only
- $144k–$168kto build 60 m², mid-range
- $175k–$230kworked example, flat block
- 60 m²standard NSW size limit
Free site feasibility check with the builder. A fixed-price contract before you sign. NSW contractor licence 258735C.
By Keiron Moore, Director of CKS Projects, with 25+ years building on the South Coast. Updated October 2026.
Important Disclaimer:
“This article is general guidance, not an exact price guide, guaranteed returns, or a substitute for professional advice or a formal quote. Construction costs, rental yields, and capital growth examples reflect 2025 conditions and will vary with site constraints, design, materials, and market movements. Speak with a qualified financial adviser before making investment decisions. For accurate estimates and design recommendations for your site, contact CKS Projects. We’ll provide a comprehensive consultation and a formal quote tailored to your Wollongong granny flat.”
Government charges are as published at the date shown and change over time.
Estimate your granny flat in three clicks
Choose the floor area, the finish and your block. The range uses CKS Projects' guide figures and the current NSW and Wollongong charges.
40 m² · Basic · Flat (CDC pathway assumed)
$105,000 – $145,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $80,000 – $96,000
- Before contingency
- $95,000 – $125,000
40 m² · Basic · Moderate slope (CDC pathway assumed)
$140,000 – $200,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $80,000 – $96,000
- Before contingency
- $125,000 – $175,000
40 m² · Basic · Steep slope (DA pathway assumed)
$195,000 – $295,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $80,000 – $96,000
- Before contingency
- $180,000 – $255,000
40 m² · Mid-range · Flat (CDC pathway assumed)
$125,000 – $165,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $96,000 – $112,000
- Before contingency
- $110,000 – $145,000
40 m² · Mid-range · Moderate slope (CDC pathway assumed)
$155,000 – $220,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $96,000 – $112,000
- Before contingency
- $140,000 – $195,000
40 m² · Mid-range · Steep slope (DA pathway assumed)
$215,000 – $315,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $96,000 – $112,000
- Before contingency
- $195,000 – $275,000
40 m² · Premium · Flat (CDC pathway assumed)
$150,000 – $210,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $120,000 – $152,000
- Before contingency
- $135,000 – $185,000
40 m² · Premium · Moderate slope (CDC pathway assumed)
$185,000 – $270,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $120,000 – $152,000
- Before contingency
- $165,000 – $235,000
40 m² · Premium · Steep slope (DA pathway assumed)
$240,000 – $360,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $120,000 – $152,000
- Before contingency
- $220,000 – $315,000
50 m² · Basic · Flat (CDC pathway assumed)
$130,000 – $175,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $100,000 – $120,000
- Before contingency
- $115,000 – $150,000
50 m² · Basic · Moderate slope (CDC pathway assumed)
$160,000 – $230,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $100,000 – $120,000
- Before contingency
- $145,000 – $200,000
50 m² · Basic · Steep slope (DA pathway assumed)
$220,000 – $325,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $100,000 – $120,000
- Before contingency
- $200,000 – $280,000
50 m² · Mid-range · Flat (CDC pathway assumed)
$150,000 – $195,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $120,000 – $140,000
- Before contingency
- $135,000 – $170,000
50 m² · Mid-range · Moderate slope (CDC pathway assumed)
$185,000 – $255,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $120,000 – $140,000
- Before contingency
- $165,000 – $220,000
50 m² · Mid-range · Steep slope (DA pathway assumed)
$240,000 – $345,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $120,000 – $140,000
- Before contingency
- $220,000 – $300,000
50 m² · Premium · Flat (CDC pathway assumed)
$185,000 – $255,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $150,000 – $190,000
- Before contingency
- $165,000 – $220,000
50 m² · Premium · Moderate slope (CDC pathway assumed)
$215,000 – $310,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $150,000 – $190,000
- Before contingency
- $195,000 – $270,000
50 m² · Premium · Steep slope (DA pathway assumed)
$275,000 – $405,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $150,000 – $190,000
- Before contingency
- $250,000 – $350,000
60 m² · Basic · Flat (CDC pathway assumed)
$150,000 – $200,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $120,000 – $144,000
- Before contingency
- $135,000 – $175,000
60 m² · Basic · Moderate slope (CDC pathway assumed)
$185,000 – $260,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $120,000 – $144,000
- Before contingency
- $165,000 – $225,000
60 m² · Basic · Steep slope (DA pathway assumed)
$240,000 – $350,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $120,000 – $144,000
- Before contingency
- $220,000 – $305,000
60 m² · Mid-range · Flat (CDC pathway assumed)
$175,000 – $230,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $144,000 – $168,000
- Before contingency
- $160,000 – $200,000
60 m² · Mid-range · Moderate slope (CDC pathway assumed)
$210,000 – $285,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $144,000 – $168,000
- Before contingency
- $190,000 – $250,000
60 m² · Mid-range · Steep slope (DA pathway assumed)
$270,000 – $380,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $144,000 – $168,000
- Before contingency
- $245,000 – $330,000
60 m² · Premium · Flat (CDC pathway assumed)
$215,000 – $300,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $180,000 – $228,000
- Before contingency
- $195,000 – $260,000
60 m² · Premium · Moderate slope (CDC pathway assumed)
$250,000 – $355,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $180,000 – $228,000
- Before contingency
- $225,000 – $310,000
60 m² · Premium · Steep slope (DA pathway assumed)
$310,000 – $450,000
With a 10–15% contingency. Excludes design, connections and landscaping
- Construction
- $180,000 – $228,000
- Before contingency
- $280,000 – $390,000
Indicative only, not a quote. Includes construction, site works, a geotechnical report, approval and occupation certificate fees, the Wollongong s7.12 levy on the cost and a 10–15% contingency. Excludes design and engineering, water, sewer and power connections, landscaping, demolition and finance costs, which CKS Projects prices for your site.
Can your block take a granny flat?
NSW calls a granny flat a secondary dwelling. The Housing SEPP sets the main rules, and your council's plans add setbacks and site coverage.
Size
Up to 60 m², or larger where your council's local environmental plan allows it.
Lot size for a CDC
At least 450 m² to use complying development. Smaller lots may still go through a DA.
One of each
Only one principal dwelling and one secondary dwelling on the lot. It can be detached, attached or within the house.
No subdivision
A lot with a secondary dwelling on it cannot be subdivided, so the granny flat can't be sold on its own title.
Source: NSW Planning, secondary dwellings (Housing SEPP). Complying development is not available in R5 Large Lot Residential zones.
What does a granny flat cost per square metre?
Finish level sets most of the rate. Small homes carry a full kitchen, bathroom and laundry in very little floor area, so the finish you choose for those rooms moves the price more than the size does.
| Finish level | Per m² | 40 m² | 50 m² | 60 m² |
|---|---|---|---|---|
| Basic | $2,000–$2,400 | $80k–$96k | $100k–$120k | $120k–$144k |
| Mid-range | $2,400–$2,800 | $96k–$112k | $120k–$140k | $144k–$168k |
| Premium | $3,000–$3,800 | $120k–$152k | $150k–$190k | $180k–$228k |
A full granny flat budget, line by line
A 60 m² detached granny flat at a mid-range finish, on a flat block in the Wollongong local government area, approved as complying development (CDC).
| Item | Low | High |
|---|---|---|
| Construction: 60 m² at $2,400–$2,800 per m² (mid-range) | $144,000 | $168,000 |
| Site preparation, flat block | $10,000 | $20,000 |
| Geotechnical report | $1,500 | $2,500 |
| Approval: CDC plus occupation certificate | $4,500 | $7,500 |
| Council contributions, Wollongong s7.12 at 0.5% of cost | $720 | $840 |
| Housing and Productivity Contribution (not charged on a granny flat) | $0 | $0 |
| Long Service Levy (only on work of $250,000 or more) | $0 | $0 |
| Subtotal | $160,000 | $200,000 |
| Contingency, 10% (low) to 15% (high) | $15,000 | $30,000 |
| Total, before the site-specific items below | $175,000 | $230,000 |
| Design, drafting and engineering | Priced for your site | |
| Water, sewer and power connections | Priced for your site | |
| Landscaping, paths and fencing | Priced for your site |
Design, connections and landscaping depend on where the granny flat sits on your block and how far the services have to run, so CKS Projects prices them after the site feasibility check rather than guessing.
The charges you do and don't pay on a granny flat
Housing and Productivity Contribution: $0
NSW Planning lists the construction of secondary dwellings among the developments that do not require the HPC.
Council contributions
Wollongong's City-Wide Development Contributions Plan (2026) levies nil up to $100,000, 0.5% from $100,000 to $200,000 and 1% above $200,000 of the cost of development. Other councils set their own plans.
Long Service Levy: often $0
The levy is 0.25% of building work of $250,000 or more. Most granny flats cost less than that, so none is payable.
BASIX
A granny flat is a new dwelling, so it needs a BASIX certificate for energy, water and thermal performance.
Home building compensation cover
Your builder must take out home building compensation (HBC) cover for residential work over $20,000.
Written contract and deposit
Work over $20,000 needs a written large-job contract, and the deposit can't be more than 10%.
Sources: NSW Planning, HPC worked examples (Example 1); Wollongong City Council, development contributions; NSW Government, Long Service Levy; NSW Planning Portal, BASIX; NSW Government, building contracts.
Kit vs custom-built granny flats: what the price leaves out
Kit and flat-pack studios are advertised at an attractive price, but the advertised price rarely reflects the cost of having one installed and approved on your block. Check whether a kit price includes:
- site preparation, a concrete slab or pier footings, and stormwater drainage
- water, sewer and power connections from the main house
- approval documentation, BASIX and structural engineering
- construction by a licensed builder, with home building compensation cover and statutory warranties
- finishes that match your existing home
A like-for-like comparison that includes all of these usually narrows the gap a long way.
Granny flat vs extension vs duplex
| Granny flat | Home extension | Duplex | |
|---|---|---|---|
| What you get | A second, self-contained home of up to 60 m² on your lot | More space in the home you have | Two homes on one lot |
| Separate title | No: the lot can't be subdivided | No | Possible, with Torrens or strata subdivision |
| Housing and Productivity Contribution | Not charged | Usually not charged | Charged for 1 net new dwelling on an existing lot |
| Cost guide | This guide | Home extension cost | Duplex cost |
Ready to compare builders? See home extension builders in Wollongong or duplex builders in Wollongong.
CDC vs DA for a granny flat
| Complying development (CDC) | Development application (DA) | |
|---|---|---|
| When it applies | The lot is at least 450 m² and every Housing SEPP standard is met | A smaller lot, an R5 zone, or a design that doesn't meet the standards |
| Approval fees | $3,000–$5,000 | $8,000–$15,000, plus a construction certificate at $3,000–$5,000 |
| Time | In as little as 20 days | 12–16 weeks minimum |
| Both pathways | An occupation certificate and a BASIX certificate |
Fee ranges are CKS Projects' guide figures. CDC timing: NSW Planning, complying development.
How CKS Projects prices a granny flat
Site feasibility check
Your lot is checked against the secondary dwelling rules and your council's controls, to confirm the size and position that's achievable.
Design for your block
A layout and finishes matched to your main home, not a catalogue.
Approvals
The CDC or DA package, including BASIX and structural engineering, lodged and managed for you.
Fixed-price contract
The full scope priced before work starts. Any variation is documented and priced before it proceeds.
More on custom studio and granny flat builders in Wollongong. Building a whole new house? See what a house costs to build in NSW. Planning a family home with room to grow? See what a 4 bedroom house costs. Comparing quotes? Read fixed price vs cost plus contracts.
Granny flat cost FAQs
How much does a granny flat cost to build in NSW?
Construction alone typically costs $2,000–$3,800 per square metre, set mostly by the finish level. A 60 m² granny flat at a mid-range finish costs about $144,000–$168,000 to build. With site works, approvals, council contributions and a 10–15% contingency it comes to about $175,000–$230,000 on a flat block, before design, service connections and landscaping, which are priced for your site.
How big can a granny flat be in NSW?
Under the Housing SEPP a secondary dwelling can be up to 60 m², or larger where your council's local environmental plan allows it. There can be only one principal dwelling and one secondary dwelling on the lot.
What size block do I need for a granny flat?
To be approved as complying development (a CDC), the lot must be at least 450 m². On a smaller lot, or where the standards aren't met, you may still be able to lodge a development application with your council.
Do you need council approval for a granny flat?
Yes. A granny flat needs either a complying development certificate, which a certifier can issue when every standard is met, or a development application to council. A new house and a granny flat can be approved together under a single CDC.
Can I subdivide and sell a granny flat separately?
No. A lot with a secondary dwelling on it cannot be subdivided. If you want two homes you can sell separately, look at a duplex instead.
Do you pay the Housing and Productivity Contribution on a granny flat?
No. NSW Planning lists the construction of secondary dwellings among the low-density developments that do not require the HPC.
Do council contributions apply to a granny flat?
In Wollongong, the City-Wide Development Contributions Plan levies a percentage of the cost of development under section 7.12: nil up to $100,000, 0.5% from $100,000 to $200,000 and 1% above $200,000. Other councils set their own plans, so ask your council for a contributions estimate.
Is a kit granny flat cheaper than a custom-built one?
The advertised kit price is lower, but it rarely includes site preparation, a slab or pier footings, stormwater, service connections or compliance certification. Compare a like-for-like, fully installed price before you decide.
How long does it take to build a granny flat?
Construction of a custom studio or granny flat typically takes 3–6 months from approval, depending on size, site conditions and specification. A CDC can be approved in as little as 20 days when every standard is met.
Does a slope add much to the cost of a granny flat?
Site works are priced on the block, not the size of the building. On CKS Projects' figures, a flat block needs about $10,000–$20,000 of site works, a moderate slope $40,000–$70,000 and a steep block $80,000–$120,000.
Find out what your block can take
Tell us your address and what you have in mind. We'll check the block for free, then price your granny flat at a fixed price before you sign.
