Car Logbook Method: The 12-Week Rule and 5-Year Validity
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Primary tax-year context: Current Australian tax settings
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General information only. This is not tax or financial advice. Consult a registered tax agent for advice specific to your situation.
If you claim work-related car expenses using the logbook method, the ATO expects a specific record-keeping standard. Done properly, the logbook method can produce larger deductions than the cents-per-kilometre method - but only if your records are compliant.
The 12-week logbook requirement
To use the logbook method, you must keep a logbook for at least 12 continuous weeks that is representative of your driving pattern. The logbook establishes your business-use percentage, which you apply to your total car expenses.
How long the logbook stays valid
A logbook is generally valid for five years. If your business-use pattern changes materially, you should keep a new 12-week logbook.
Records you must keep
In addition to the logbook itself, you must keep:
- Odometer readings for the start and end of the logbook period and each income year
- Receipts and invoices for fuel, servicing, insurance, registration, and other car running costs
- Evidence of work-related trips (for example, diary notes or appointment records)
Common mistakes to avoid
- Using a logbook that isn’t continuous or representative
- Failing to record odometer readings at year end
- Claiming trips that are private or home-to-work travel
Key takeaways
- Keep a 12-week continuous logbook to establish your business-use percentage.
- The logbook is valid for five years unless your usage changes.
- Save all car expense receipts and odometer readings to support the claim.
If your pattern of driving changes materially, start a new logbook immediately.