The ATO Logbook Method Explained

A plain-English guide · Updated 2026

If you use your car for work, the logbook method usually lets you claim more than the cents-per-kilometre method — but only if your records are complete. Here's how it works, what you need to record, and how to make it painless.

What is the logbook method?

The ATO offers two ways to claim car expenses for work-related driving: the cents per kilometre method (a set rate for up to 5,000 business km, no logbook required) and the logbook method. The logbook method lets you claim your business-use percentage of your actual car running costs — fuel, servicing, registration, insurance, depreciation and more — which is often a larger deduction if you drive a lot for work.

The catch: you need a valid logbook to prove that percentage.

The 12-week rule

To establish your business-use percentage you must keep a logbook for a minimum continuous period of 12 weeks. A few important details:

• Continuous: the 12 weeks must be one unbroken block — you can't stitch together separate weeks.
• Representative: the period should fairly reflect your typical driving across the year. Avoid unusual stretches like annual leave or an unusually quiet (or busy) month.
• Every trip counts: you must record every journey during those 12 weeks — both business and private.

What you need to record

For the logbook period, keep a record of:

• The start and end dates of the logbook period
• The odometer readings at the start and end of the period
• The total kilometres travelled during the period
• For each journey: the date, reason/purpose, and kilometres travelled (business trips in particular)

You also record the odometer reading at the end of each income year so you can apply your business-use percentage to the total kilometres you drove that year.

Item	When to record
Odometer — start of period	First day of the 12 weeks
Each trip: date, purpose, km	Throughout the 12 weeks
Odometer — end of period	Last day of the 12 weeks
Odometer — end of income year	30 June each year

How long does a logbook last?

A logbook is generally valid for five income years, as long as your circumstances haven't changed materially (for example, a big change in how much you drive for work). After five years — or sooner if your usage changes significantly — you'll need to keep a fresh 12-week logbook.

Working out your business-use percentage

The formula is simple:

You then apply that percentage to your actual car expenses for the year. For example, if your logbook shows 70% business use and your total running costs were $8,000, you could claim 70% — $5,600 — subject to the usual ATO rules and substantiation.

Common mistakes to avoid

• Missing private trips. The logbook must capture all travel, not just work trips — otherwise the percentage is wrong.
• Gaps in the 12 weeks. Forgetting to log for a few days can invalidate the continuous-period requirement.
• An unrepresentative period. Choosing your busiest work weeks inflates the percentage and won't hold up.
• No odometer readings. Start/end-of-period and end-of-year readings are easy to forget but required.

Make it automatic

The hardest part of the logbook method is the discipline — remembering to record every single trip for 12 weeks straight. That's exactly what AutoTripLogger is built for: it detects and records each drive automatically in the background, separates business from personal, and lets you export a clean 12-week summary as a CSV when it's time to lodge.

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