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Understanding Partial Main Residence Exemption for CGT

Published 26 June 2026 · Last updated 26 June 2026

Quick Answer

The partial main residence exemption for CGT allows Australian property owners to reduce their capital gains tax if their home was not solely used as a main residence during ownership. This exemption is complex, requiring precise calculations based on the period the property was used for personal residence versus other uses, such as rental.

The partial main residence exemption for Capital Gains Tax (CGT) is a valuable provision for Australian property owners who have used their main home for other purposes, such as rental. This exemption helps reduce the CGT payable when selling a property that was not your main residence for the entire ownership period.

Under Subdivision 118-B of the Income Tax Assessment Act 1997, a full CGT exemption is available if the property was your main residence throughout the entire ownership period. However, when a property has been used for both private and income-producing purposes, a partial exemption may apply. This is often misunderstood, with many investors failing to correctly calculate the exempt portion.

To determine the partial exemption, you must calculate the proportion of time the property was used as your main residence versus the time it was rented or otherwise income-producing. This involves considering the total ownership period and the periods of different uses. The most common misconception is that any period of rental disqualifies a property from the main residence exemption entirely, which is not the case.

To see how this plays out, consider a practical example. Imagine you purchased a two-bedroom apartment in Bondi, Sydney, in January 2015 for $800,000. You lived there for three years, then rented it out for two years before selling it in January 2020 for $1,200,000. During your ownership, the property was your main residence for 60% of the time (3 out of 5 years). Therefore, 60% of the capital gain is exempt. The total gain is $400,000. With the partial exemption, $240,000 is exempt, leaving $160,000 subject to CGT. At a 37% tax rate, this results in a CGT liability of $59,200.

In our experience reviewing thousands of properties across Australia, many investors overlook the importance of maintaining accurate records of their property's usage. This is crucial for substantiating claims for partial exemptions. Additionally, some investors mistakenly believe that temporary absences (such as living overseas) automatically disqualify them from the exemption, which is not always the case. Another common oversight is failing to account for the 'six-year rule', which allows you to treat a property as your main residence for up to six years while it is rented out.

The answer can differ depending on your situation. If you purchased a property before 20 September 1985, it is exempt from CGT. For properties acquired after this date, the exemption depends on the property's use. If you use the property for business purposes, different rules may apply. Properties held in a trust or by a company do not qualify for the main residence exemption at all. If you own the property jointly, each owner's usage must be considered separately.

Given the complexity, obtaining professional advice is crucial. A Chartered Quantity Surveyor can provide a detailed assessment of your property's historical usage and potential CGT implications. An accountant can help integrate this information into your overall tax strategy, ensuring you maximise any available exemptions.

Here are some practical steps you can take:

  • Review your property records to determine periods of personal and rental use.
  • Calculate the proportion of time the property was your main residence.
  • Consider the impact of the 'six-year rule' if applicable.
  • Consult with a Chartered Quantity Surveyor for an accurate assessment.
  • Discuss your situation with an accountant to ensure compliance and optimisation.
  • Keep detailed records for any future audit or review.
  • Frequently Asked Questions

    How does the partial exemption affect my tax return?

    The partial exemption reduces the capital gain subject to tax. You must accurately report the exempt and taxable portions on your tax return to avoid discrepancies.

    Can I apply the partial exemption to a property in Queensland?

    Yes, the partial main residence exemption applies across all Australian states, including Queensland. However, local property laws do not affect CGT exemptions.

    Does the partial exemption apply if I move overseas?

    Yes, the partial exemption can still apply if you move overseas, provided the property remains your main residence for a portion of the ownership period.

    What if I use part of my home for business?

    Using part of your home for business may affect the exemption. The exemption is pro-rated based on the percentage of the property used for private versus business purposes.

    How do joint ownerships affect the exemption?

    In joint ownership, each owner must calculate their own main residence usage. The exemption applies to each owner's share individually.

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    Written by Koste Team · Koste Chartered Quantity Surveyors · AIQS Member · RICS Member · TPB Registered · 1300 669 400 · info@koste.ai