Capital Gains Tax on Property: The 6-Year Rule and Other Things Most People Get Wrong

Capital gains tax on property is one of those topics that starts as “yeah yeah, I’ll deal with it later” and ends with someone staring at an accountant’s email like it contains a bomb. The good news is CGT is not random. The bad news is a lot of people confidently repeat rules they only half understand, especially around the famous 6-year rule.

If you have moved out of a home, rented it out, bought another place, or are trying to work out whether selling now will trigger tax, this is the bit that matters. In Australia, your main residence is generally exempt from CGT, but the exemption gets more complicated the moment the property starts producing income.

This guide covers the 6-year rule, partial exemptions, the market value reset rule, and the common mistakes that quietly turn into expensive ones.

First, what CGT on property actually is

Capital gains tax is not a separate tax rate. It is part of your income tax. If you sell a property for more than its cost base, the gain is generally added to your taxable income in the year the contract is signed.

For property, your cost base can include more than just the purchase price. It can include things like stamp duty on purchase, legal fees, buyers agent fees, and selling costs such as agent commission and solicitor fees. Not every repair or holding cost goes in automatically, so this is where records matter more than vibes.

If the property was always your principal place of residence and was not used to produce income, the main residence exemption usually means no CGT at all. Lovely. Almost suspiciously lovely.

The 6-year rule, in plain English

The ATO allows you to keep treating a former home as your main residence for up to 6 years while it is used to produce income, such as rent, after you move out. This is the rule people talk about when they say, “just rent it out for six years and you’re sweet.”

That sentence is not completely wrong. It is just missing all the bits that matter.

To use the rule, the property generally needs to have been your main residence first. You cannot buy an investment property, rent it out immediately, then later decide it was spiritually your home all along. The ATO is strangely unsentimental about spiritual real estate.

While you choose to keep treating that old home as your main residence, you generally cannot also treat another property as your main residence for the same period, apart from the limited 6-month overlap concession when moving between homes.

So the 6-year rule is really a choice. You are choosing which property gets the exemption for that period. That choice can be extremely valuable, but it is not automatic and it is not always best to use it the same way in every scenario.

Common mistake number 1: thinking the 6-year rule applies if the property was never your home

This is the big one. The property needs to have been your main residence first. If it was a rental from day one, the 6-year rule does not magically convert it into an exempt property later.

That is why owner-occupiers who move out and keep the place as an investment often have better CGT options than people who bought a pure investment property from the start. Same bricks, completely different tax treatment.

Common mistake number 2: assuming the clock runs forever if the property is only rented sometimes

The 6-year limit is tied to periods when the property is used to produce income. According to ATO guidance, if you move out, rent the property for a period, then leave it vacant, the vacant period is not counted the same way as an income-producing period. If the total rental use in that absence stays within 6 years, you may still be able to cover the whole absence.

That does not mean every odd gap resets the rule. It just means the tax outcome depends on what happened during each absence. This is why “my mate said it resets if you take Airbnb bookings off for a month” is not planning. That is pub theatre.

Common mistake number 3: not realising the 6-year rule can reset after you move back in

This part is genuinely useful. The ATO says the 6-year limit applies separately to each period of absence immediately following a period when you lived in the property again as your main residence.

So if you live in the home, move out and rent it for 5 years, move back in for a while, then move out and rent it again, the second absence can get its own 6-year period. That is very different from saying you get only one 6-year ticket for the entire life of the property.

If you are mapping out a move for work, a temporary interstate stint, or a period where your former home becomes an investment property, this rule can materially change the maths.

Common mistake number 4: forgetting you cannot freely claim two main residences

People often buy a new home, keep the old one, and assume both somehow qualify because one was their “real home” and the other is their “actual actual home”. Tax law does not care how emotionally attached you are to the first house.

If you choose to keep treating the old property as your main residence under the 6-year rule, you usually give up claiming the new property as your main residence for the same period, except for the limited overlap when moving. In some cases that is still the right choice. In others, it creates a bigger future tax bill on the new home.

This is why you should compare both properties before deciding. A smaller gain on the old property and a much bigger gain building on the new one can flip what looks obvious at first glance.

Common mistake number 5: using the wrong starting value once the property first earns rent

If your home was your main residence and you first use it to produce income after 20 August 1996, there is an important rule that can help. If you would have qualified for a full main residence exemption just before it first earned income, you generally treat the property as acquired at its market value on that date for CGT purposes.

That matters because if you eventually exceed the 6-year rule or only get a partial exemption, the taxable gain is often worked out from that market value reset point, not from what you originally paid years earlier.

In plain English, if your place doubled in value while you lived in it, that earlier growth may effectively be washed out for CGT calculations once the rule applies. Miss that and you can wildly overestimate the tax.

Common mistake number 6: thinking contract date does not matter

For Australian CGT, the relevant date is usually the contract date, not settlement. That catches people out all the time.

If you sign a contract on 28 June and settle in August, the CGT event generally belongs in the earlier financial year. If you are planning around tax brackets, carried-forward capital losses, or a year where your income is unusually high or low, that timing matters.

Settlement still matters for life. Contract date matters for CGT.

Common mistake number 7: forgetting partial exemptions exist

Property CGT is not always all or nothing. If you exceed the 6-year limit during one absence, or only part of the ownership period qualifies for the main residence exemption, you may get a partial exemption rather than losing the whole thing.

That is often much better than people fear. The taxable portion is usually based on the non-exempt days over the relevant ownership period after the deemed market-value acquisition point. Then, if you are an individual or trust and the asset was held for at least 12 months, the 50% CGT discount may still reduce the remaining gain.

So no, going one day over 6 years does not mean the entire gain becomes taxable from the original purchase date. Tax is painful enough without inventing extra pain.

Common mistake number 8: using part of the home for business and assuming the 6-year rule fixes it later

If part of your home was used to produce income before you moved out, such as a dedicated surgery, studio, or business area, that part may stay exposed to CGT even if you later choose to keep treating the property as your main residence during an absence.

The continuing main residence rule does not magically erase prior income-producing use of that part. If your setup was more than the usual work-from-home laptop-on-the-dining-table situation, get advice. This is where “home office” can mean two completely different things in ordinary conversation and tax law.

Common mistake number 9: ignoring foreign residency rules

This one is nasty because older advice floating around online can be outdated. In general, foreign residents are not entitled to the main residence exemption when a CGT event happens to Australian residential property, unless a limited life events test applies.

So if you move overseas and become a foreign resident for tax purposes, do not assume the 6-year rule will protect you the same way it would if you were still an Australian resident for tax purposes. This is absolutely one of those areas where “close enough” can become very expensive.

A quick example

Say you bought a Melbourne unit in 2018, lived in it until 2022, then moved in with a partner and rented the unit out. If you sell it in 2027 and choose to keep treating it as your main residence during that rental period, you may be able to ignore the gain entirely, assuming you are not choosing another property as your main residence for the same period beyond any allowed overlap.

If instead you keep renting it until 2031 without moving back in, part of the post-rental-period gain may become taxable because you are more than 6 years into the same income-producing absence. That taxable slice is where the market value at first income use can become very important.

What records should you keep?

• purchase contract and settlement statement
• stamp duty and legal costs
• valuation at the date the home first produced income, if relevant
• rental statements and dates the property was rented or genuinely available for rent
• selling costs like agent commission and legal fees
• dates you moved in, moved out, and moved back in

If you are relying on the 6-year rule years later, those dates matter more than your memory. Human memory is great for awkward conversations from 2014 and terrible for tax chronology.

The bottom line

The 6-year rule is real, useful, and often misunderstood. It can save property owners a lot of money, but only if the property was your main residence first, you understand the overlap rules, and you track the timing properly.

The biggest mistakes are assuming the exemption is automatic, assuming you can claim two homes at once, and forgetting the market value reset when the property first starts earning income. Get those right and the whole picture becomes much less mysterious.

If your situation involves multiple moves, a new partner, business use, or foreign residency, stop guessing and get tax advice before you sign a contract. CGT planning works best before the sale, not after the money lands and the regret arrives.

FAQ

Does the 6-year rule mean I pay no CGT if I rent out my old home for exactly 6 years?

Often yes, but only if the property was your main residence first and you choose to keep treating it as your main residence during that absence. You also generally cannot claim another property as your main residence for the same period, apart from the limited overlap concession.

Can the 6-year rule reset if I move back into the property?

Yes. The ATO says the 6-year limit applies separately to each period of absence immediately following a period when you lived in the property again as your main residence.

What date matters for CGT, contract or settlement?

Usually the contract date. That is the year the capital gain, loss, or exemption is generally reported.

Can I use the 6-year rule if the property was an investment from day one?

No. The property generally must have been your main residence first.

Do I still get the 50% CGT discount?

If you are an eligible taxpayer such as an individual or trust and the asset was held for at least 12 months, the 50% discount may still apply to the taxable part of the gain. Companies do not get the 50% discount.