ATO Logbook Method Guide
Choose this guide when you need the detailed deduction method rather than the simpler cents-per-kilometre cap.
At a glance
- The logbook method uses actual car costs multiplied by your business-use percentage.
- A valid logbook covers a continuous 12-week period and can generally support claims for 5 years while circumstances stay the same.
- Unlike the cents-per-kilometre method, the logbook method needs written evidence for car expenses.
When the logbook method is worth the effort
The logbook method is the heavier admin option, but it can produce a larger deduction when work-related use is high and the car is expensive to run. That is the tradeoff: more substantiation in exchange for a claim tied to real costs rather than a capped per-kilometre proxy.
For people deciding between the two ATO methods, the real question is not which method sounds simpler. It is whether your business-use percentage and actual operating cost justify the extra recordkeeping.
What a valid logbook needs
ATO guidance lets you keep using a valid logbook for up to 5 years if the pattern of use stays materially the same. That makes the first setup effort more worthwhile than many taxpayers assume.
- A continuous 12-week logbook period that represents normal use of the car.
- Odometer records for the start and end of the logbook period and the income year.
- Trip-level details that support the business-use percentage.
- Written evidence for the car expenses you are claiming under the method.
How to avoid a weak claim
The weak version of a logbook claim is a percentage with no paper trail behind it. The strong version is a logbook, odometer positions, and receipts that all point to the same business-use story.
If you are not ready to maintain that file, use the cents-per-kilometre method instead of improvising a half-logbook. The ATO framework rewards consistency much more than optimism.
Official references
Overview of both car-expense methods.
Recordkeeping expectations for logbooks and supporting evidence.
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