Quick answer: a duplex can be a good investment when two rents from one block beat one house on cash flow and the title and lending suit you. If you live in one side and rent the other, the ATO treats the rented side as an investment, so you lose part of the CGT main residence exemption.
Updated 28 October 2026. Tax rules checked on the ATO and Treasury websites on 28 October 2026, planning rules on the NSW Planning and Brisbane City Council websites on 19 October 2026.
Key facts, with dates and sources
These five facts decide most duplex purchases in Australia: how the ATO treats a home you rent out in part, what interest you can deduct, when the 2026 negative gearing and capital gains tax changes start, and the minimum lot size for a dual occupancy in NSW. Each fact shows its source and the date it was checked.
- Renting out part of your home means you are not entitled to the full CGT main residence exemption, but may get a partial exemption (ATO, updated 22 June 2026, checked 28 October 2026).
- You can claim a deduction for the home loan interest related to the portion of your home that is rented out (ATO, updated 22 June 2026).
- The Treasury Laws Amendment (Tax Reform No. 1) Act 2026 was assented to on 26 June 2026 and the ATO says the negative gearing and CGT measures are now law (ATO, updated 29 June 2026).
- From 1 July 2027 negative gearing of residential property is limited to new builds and the 50 per cent CGT discount is replaced with cost base indexation and a 30 per cent minimum tax rate on gains that accrue after that date (ATO).
- In NSW low and mid-rise housing areas the minimum lot size for a dual occupancy is 450 square metres (NSW Planning, updated 21 March 2025).
What is a duplex?
A duplex is two separate homes on one block, usually side by side and joined by a shared wall, each with its own entry, kitchen and bathroom. Councils often call it a dual occupancy. The two homes can sit on one title or be split into two titles, which changes how you can sell, borrow and rent.
A duplex is two separate homes built on one block, usually side by side and joined by a shared wall. Each home has its own entry, kitchen, bathroom and living areas. Councils often call it a dual occupancy: NSW Planning describes dual occupancies as "2 homes built on one lot of land", and Brisbane City Council uses the term for two dwellings on one lot (attached or not) or on separate lots that share common property.
You will see a few names for similar homes:
- Duplex or dual occupancy: two full homes on one block, on one title or split into two titles.
- Dual key: one building with two self-contained parts, often a main home plus a smaller unit, sold on one title.
- House and granny flat: a main home plus a smaller second dwelling behind it, usually on one title.
- Semi-detached or townhouse: often one half of a pair or row, sold on its own title, so you own one home, not two.
Why buy a duplex: the three ways to use one
| Plan | What it looks like | Main upside | Main watch-out |
|---|---|---|---|
| Live in one side, rent the other | Your home plus a tenant next door | Rent from one side helps pay the loan | Partial CGT exemption; your tenant is your neighbour |
| Rent both sides | Two rental incomes from one block | Higher combined rent than one house on similar land | Two sets of repairs, vacancies and tenants |
| Buy one side | One home on its own title, with a neighbour owner | Lower entry price | Shared wall, fences and outside works need the other owner's agreement |
Owning both sides on one block gives you the most control: one set of decisions, and the choice to sell the pair together, or separately if the titles are split. Buying one side is closer to buying a townhouse: cheaper, but you share decisions about the common wall, roof lines, fences and driveway with someone else.
Duplex investment pros
The main advantages of a duplex are two rents from one block, vacancy risk spread across two homes, an affordable way to live in one side while renting the other, and choices later if the titles are split. The trade-off is less land per home, so check the street and the build.
- Two rents from one block. Two smaller homes often rent for more in total than one larger house on a similar block, which can lift your gross yield and help with cash flow.
- Vacancy risk is spread. If one side is empty between tenants, the other side is still paying rent.
- A way into the market. Living in one side and renting the other can make a home affordable that would be out of reach on one income.
- Choices later. On separate titles you may be able to sell one side and keep the other, refinance each side, or move from one side to the other as life changes.
- Family living. Two homes on one block suit adult children, ageing parents or extended families who want to live close but separately.
- New-build tax position. Under the Tax Reform No. 1 Act 2026, negative gearing of residential property is limited to new builds from 1 July 2027. A newly built duplex may fall on the new-build side of that line; confirm how a new build is defined for your duplex with your accountant before relying on it.
Duplex investment cons and risks
The main risks of a duplex are slower capital growth than a free-standing house, a smaller pool of buyers when both sides are sold together, tougher lending, shared-wall noise and two sets of upkeep. Check the title, the lender's view and the building inspection before you commit to a purchase.
- Capital growth can trail a house. Much of a property's long-term growth comes from the land. When the land is shared between two homes, each home carries less of it, and some buyers prefer a free-standing house. Growth depends on the suburb, the build and the demand for duplexes in that street.
- A smaller pool of buyers. A pair on one title is normally sold as a pair, which suits investors more than home buyers. That can make it slower to sell.
- Lending can be harder. Lenders look closely at the title, the zoning and how much of the rent they count when working out what you can borrow. Speak to a broker before you sign a contract.
- Shared walls and noise. Sound and fire separation between the two homes matter for comfort and for the building rules. Check them in the building and pest inspection.
- Two lots of upkeep. Two kitchens, two bathrooms, two hot water systems and two sets of tenants mean more repairs and more management.
- Owning just one side. Outside changes, shared fences and repairs to the common wall need your neighbour's agreement, and on a strata title the owners corporation and its by-laws apply.
Tax when you live in one side and rent the other
This is where many duplex buyers get caught out. The ATO's guidance on using your home for rental says that if you rent out part of your home you are not entitled to the full main residence exemption from CGT, but you may be entitled to a partial exemption. In plain words:
- The rent is income. Rent from the other side goes in your tax return.
- You can claim the rented share of the costs. The ATO says you can claim a deduction for the home loan interest related to the portion of your home that is rented out. The share is usually worked out by floor area, then by the days it was rented.
- The rented share is exposed to CGT. The gain on the rented portion during the rental period is assessable. The ATO also says that if you are, or would be, eligible to claim part of the interest, your home is subject to CGT to the same extent, so you cannot avoid CGT by not claiming the interest.
- Land used for income is not exempt. The main residence exemption can cover up to 2 hectares of land around your home, but any part of the land used to produce income is not exempt, even on a small block.
- The home first used to produce income rule. If you lived in the home first and rent part of it out later, the gain may be worked out from the home's market value on the day it was first used to produce income, not from what you paid. Sell within 12 months of that day and the ATO says you can't use the CGT discount.
Whether the two sides are one dwelling or two separate dwellings, on one title or two, changes how these rules apply. Get advice from a registered tax agent before you buy, not after.
What the 2026 negative gearing and CGT changes mean for duplex buyers
The negative gearing and capital gains tax changes are now law. From 1 July 2027, negative gearing of residential property is limited to new builds, with homes held before 7:30pm AEST on 12 May 2026 exempt, and the 50 per cent CGT discount is replaced by indexation and a 30 per cent minimum tax rate on gains.
The Treasury Laws Amendment (Tax Reform No. 1) Act 2026 was assented to on 26 June 2026, and the ATO says these measures are now law. Properties held at the Budget announcement (7:30pm AEST on 12 May 2026) are exempt from the negative gearing changes. For established homes bought after that time, the Budget papers said losses could be deducted against other residential property income, including capital gains, and carried forward, but not against wages. From 1 July 2027 the 50 per cent CGT discount for individuals, trusts and partnerships is replaced with cost base indexation and a 30 per cent minimum tax rate on capital gains, and the reforms apply only to gains that accrue after 1 July 2027. The ATO page does not define a new build, so confirm how it applies to the duplex you are looking at with your tax agent before you buy.
For a duplex buyer, the practical question is simple: is this an established duplex bought after 12 May 2026, or a new build? The answer changes how any loss on the rented side can be used. Our guide to positive vs negative gearing walks through the cash flow side.
One title or two? Strata, Torrens and community title
A duplex can sit on one title for the whole block, on two Torrens titles with one home each, or on strata or community title with shared parts. The title decides whether you can sell, refinance or rent each side separately, what levies apply, and how a lender treats the property.
- One title (both homes on one lot): you own the whole block and both homes. You usually have to sell them together unless you subdivide later.
- Torrens title for each side: each home sits on its own lot. You can sell, rent or refinance each side on its own. Shared walls and fences are handled between neighbours.
- Strata or community title: each home is a lot, with shared parts managed by an owners corporation or body corporate. There may be levies, building insurance arranged by the scheme, and by-laws that affect pets, renovations and short stays. Read our guide to buying a strata property before you buy.
Splitting one title into two later needs council approval and a subdivision, which costs money and time, and the rules differ by council. In NSW, dual occupancies are permitted with consent in R2 zones state-wide under the low and mid-rise housing policy. In the low and mid-rise housing areas near nominated town centres and stations it sets a minimum lot size of 450 square metres and a minimum width of 12 metres, and subdivision down to 225 square metres a lot in R1 to R3 zones. In Brisbane a dual occupancy is either code assessable or impact assessable, depending on the zone, and then needs building approval from a licensed building certifier.
Financing a duplex
Lenders look at the title, how much of the rent they will count, and whether you will live in one side. An owner-occupier loan may cover the part you live in, but the rented side is an investment for tax. Speak to a broker and get pre-approval that names the property type first.
Lenders look at three things on a duplex: the title (one or two), how much of the rent they will count, and whether you will live there. Living in one side may let you use an owner-occupier loan for part of the purchase, but the rented side is still an investment for tax. Many buyers keep the loans for each side separate so the interest split is clear. Talk to a broker about borrowing power, the deposit and lenders mortgage insurance before you make an offer, and get pre-approval that names the property type.
Duplex buying checklist
- Confirm the title: one lot, two Torrens lots, strata or community title.
- Check the council approvals for both homes, and any conditions on use.
- Get a building and pest inspection that covers the shared wall, fire separation, roof and drainage.
- Get a rental appraisal for each side from a local property manager.
- Compare recent sales of duplexes in that street with free-standing houses nearby.
- Ask your broker how the lender treats the title and the rent.
- Ask your tax agent how the CGT exemption and interest split will work for your plan.
- Buying just one side: read any strata by-laws or shared-wall arrangements and meet the neighbour if you can.
Duplex vs house vs townhouse
| Duplex (both sides) | Free-standing house | Townhouse or one side of a duplex | |
|---|---|---|---|
| Rental income | Two rents | One rent | One rent |
| Land share | Whole block, split between two homes | Whole block, one home | Small or shared |
| Who decides on changes | You | You | Shared with neighbours or a body corporate |
| Buyer pool when selling | Mostly investors (if one title) | Home buyers and investors | First home buyers, downsizers, investors |
| Upkeep | Two homes | One home | One home plus levies |
Should you use a buyers agent for a duplex?
A duplex has more moving parts than a house: title, approvals, two rents, lending and tax. A buyers agent can check those before you commit, compare the duplex with houses and townhouses nearby, and negotiate the price. Wealth Through Property's investment property buyers agent service is a fixed $12,000 for purchases up to $1 million, then 0.4% on the part from $1 million to $2 million (GST included), with payment plans. You can work out the fee for your price on the buyers agent fee calculator, or read how fees compare across the market in our buyers agent fees guide. Buying a duplex to live in? See our home buyers agent service.
Related reading: cash flow in property investment, rentvesting pros and cons and new vs established property.
More duplex questions
Does a duplex count as my home or an investment?
It can be both. The side you live in is your home for tax and lending, and the side you rent out is an investment. How the rules apply depends on whether the two homes are one dwelling or two, and on one title or two, so ask a registered tax agent before you buy.
What is the difference between a duplex and dual occupancy?
In everyday use they mean much the same thing: two homes on one lot of land. Dual occupancy is the planning term councils use. A duplex usually means the two homes are attached side by side, while a dual occupancy can also be two detached homes on the same block.
What is the difference between a duplex and a townhouse?
Buying a whole duplex gets you two homes and two rents on one block. A townhouse is one home in a pair or row, often on strata title with levies and by-laws. Buying one side of a duplex is closer to buying a townhouse: cheaper, but you share decisions with a neighbour.
Do duplexes grow in value as much as houses?
Not in every case. Much of a property's long-term growth comes from the land, and in a duplex the land is shared between two homes. Some buyers also prefer a free-standing house. Growth depends on the suburb, the quality of the build and how many buyers want duplexes in that street.
Is it harder to get a loan for a duplex?
It can be. Lenders look at whether the duplex is on one title or two, the zoning, how much of the rent they will count and whether you will live there. Talk to a broker and get pre-approval that names the property type before you make an offer.
How do the 2026 negative gearing changes affect duplex investors?
The ATO says these changes are now law. From 1 July 2027 negative gearing of residential property is limited to new builds, and properties held at 7:30pm AEST on 12 May 2026 are exempt. An established duplex bought after that time is not covered by the exemption, so ask your tax agent how any loss on the rented side can be used.
Should I use a buyers agent to buy a duplex?
A buyers agent helps when a purchase has many moving parts. With a duplex that means title, approvals, two rents, lending and tax. Wealth Through Property's investment property buyers agent fee is a fixed $12,000 up to $1 million (GST included), with payment plans available.
Sources
- ATO: Using your home for rental or business (last updated 22 June 2026, checked 28 Oct 2026)
- ATO: Tax reform, boosting home ownership, reforming negative gearing and capital gains tax (last updated 29 June 2026, checked 28 Oct 2026)
- Treasury Laws Amendment (Tax Reform No. 1) Act 2026, Act No. 49 of 2026 (assented to 26 June 2026)
- ATO: Home on more than 2 hectares (last updated 22 June 2026)
- Treasury: Budget 2026-27 tax measures and Budget 2026-27 tax reform
- NSW Planning: Low and mid-rise housing, summary of key provisions (updated 21 March 2025)
- Brisbane City Council: Dual occupancy
This article is general information and is not financial, tax or legal advice. It does not take your personal circumstances into account. Speak to a licensed financial adviser, registered tax agent or solicitor before acting.
Thinking about buying a duplex?
Book a free call with Scott and the Wealth Through Property team. We will look at the duplex, the title, the rents and the street with you before you make an offer. Contact us or see how our investment property buyers agent service works.