Most buyers never meet this rule. It matters if you are buying more than one thing at once: two adjoining lots, a house and the block beside it, or a package where the land and something else are bought together.
Why aggregation costs you money
Transfer duty is charged on a sliding scale, so the rate climbs as the value rises. Two $500,000 purchases assessed separately each attract duty at the rate that applies to $500,000. Assessed as one $1,000,000 transaction, the whole amount is pushed up the scale.
That difference is the entire point of the rule. It stops a single large purchase being split into smaller ones to land in a lower bracket.
When do separate purchases get aggregated?
All three states ask the same central question: do the transactions really amount to one arrangement? They differ on the detail around it.
| New South Wales | Queensland | Victoria | |
|---|---|---|---|
| The core test | The transferors are the same or associated, the transferees are the same or associated, and the transactions form substantially one arrangement | Transactions that together form, evidence, give effect to or arise from what is substantially one arrangement | The transactions occur within 12 months of each other, and form substantially one arrangement |
| Time limit | None. The 12-month limit was removed on 4 September 2023. | None set in section 30 | 12 months |
| Optional? | No | No, aggregation is compulsory | No |
| Main carve-out | Vacant allotments bought by a licensed residential builder to build homes for sale | None set out in section 30 | Vacant land bought by a registered domestic builder to build homes for sale |
| Where it sits | Section 25, Duties Act 1997 | Section 30, Duties Act 2001 | Section 24, Duties Act 2000 |
Queensland and Victoria look at this slightly differently, which is worth knowing if you are buying across borders. Queensland weighs whether the parties are the same or related as one factor among several. Victoria looks primarily at the relationship between the transactions themselves rather than at who the parties are.
What counts as "substantially one arrangement"?
There is no single rule, and each case turns on its facts. The things revenue offices look at include:
- whether the transactions are set out in one document
- whether each is conditional on the others completing
- whether the parties are the same, or related to each other
- how close together in time they happened
- whether the properties were used together before the sale, or will be afterwards
None of these decides it alone. Two lots bought from the same seller on the same day, under contracts that each fall over if the other does, is an obvious case. Two unrelated purchases from different sellers six months apart is not.
When does this actually affect a home buyer?
Rarely, but it does happen:
- Buying a house and the vacant block next door, whether at the same time or as part of one negotiated deal.
- Buying two units in the same building, particularly from the same seller.
- House and land arrangements where the land and the build are structured as separate transactions.
- Buying with family, where related parties each take a share of adjoining properties.
If any of those describe your purchase, raise it with your conveyancer before you sign, not after. Duty is assessed on what the arrangement actually was, so restructuring it afterwards does not help.
What you should do
Tell your conveyancer the whole picture. If you are buying more than one property, or buying one property in more than one piece, say so early. The duty position is easier to plan for before contracts are signed than to argue about once an assessment has issued.
Each revenue office publishes its own guidance: Revenue NSW, the Queensland Revenue Office and the State Revenue Office Victoria.
Common questions
Does aggregation apply if I buy from two different sellers?
It can. In Queensland and Victoria the test centres on whether the transactions form one arrangement, so different sellers does not automatically put you outside it. In New South Wales the transferors must be the same or associated.
Will I be charged duty twice?
No. Where duty has already been paid on an earlier transaction that is later aggregated, it is credited against the total rather than charged again.
Can I just sign the contracts months apart?
Timing is one factor, not a workaround. Victoria has a 12-month window, while Queensland and New South Wales set no fixed time limit, so spacing contracts out does not by itself prevent aggregation if the arrangement is plainly one deal.
General information only, not legal or tax advice. Duty law varies by state and changes over time; confirm your position with a licensed conveyancer, solicitor or the relevant revenue office.
