The ATO 12-Week Logbook: How to Keep One That Holds Up

You drive a lot for work — deliveries, rideshare, trades, visits to clients — and the cents-per-kilometre method stops paying at 5,000 km a car. The logbook method has no cap: you claim your business-use percentage of what the car actually costs. The catch is the logbook, and most people put it off because “twelve weeks of writing down every trip” sounds like a second job.

The short answer: the first year you use the logbook method, keep a logbook for at least 12 continuous weeks that represent how you drive across the year. Record the odometer at the start and end of that period, and for every work trip the date, the odometer at the start and end, the kilometres and a real reason for the trip. The percentage it proves is good for five years, as long as you also note the odometer at the start and end of each income year and your driving does not change.

Do you need a logbook at all?

Probably not, if you drive under 5,000 business kilometres a year. The cents-per-kilometre method pays 91c a kilometre for 2026–27, capped at 5,000 km per car, with no logbook and no receipts — you only have to show how you worked the kilometres out. The ATO cents per km page covers that method and the cap.

Past 5,000 km, or with an expensive car, the logbook method usually claims more, because it has no ceiling. It needs two things: the logbook, which proves your business-use percentage, and the receipts for what the car cost to run.

What the logbook has to show

From the ATO's guidance, the logbook period needs:

• When it begins and ends — at least 12 continuous weeks.
• The odometer reading at the start and the end of the period.
• The total kilometres the car travelled in that time.
• The kilometres of the work journeys, added up from the journeys you recorded.
• Your business-use percentage — work kilometres divided by total kilometres.

And for every work journey:

• the date it started and finished;
• the odometer reading at the start and end of the journey;
• the kilometres travelled;
• the reason for the journey. The ATO says an entry of “business” or “miscellaneous business” will not be enough: it has to say what the trip was for.

The five years after

Each logbook is valid for five years, and you can start a new one at any time. In the years you rely on it without keeping a new one, you still keep the logbook itself and record the odometer at the start and end of each income year — 1 July and 30 June. If your circumstances change, for example the kind of work you do, you may need a new logbook.

If you replace the car and carry the percentage over, the ATO asks for the odometer readings of both the old car and the new one on the day you swapped.

Where logbooks go wrong

• Gaps. Twelve weeks is 84 days of trips. The ones that go missing are the short hops between jobs, which are exactly the business kilometres you are trying to prove.
• Private trips missing from the total. The percentage is business over total. The odometer at each end catches this: if tracked trips add up to less than the odometer difference, some driving was not recorded.
• Vague reasons. “Work” forty times in a row is the entry the ATO calls out.
• Losing it in year three. The logbook is still your evidence for years four and five. Keep a copy somewhere other than the phone you kept it on.

Keeping it in TaxMiles

With your region set to Australia, the Taxes tab's Tax Toolkit has a Logbook screen. You choose the car, the start date and the opening odometer reading, and TaxMiles then records every drive automatically for the 12 weeks while you classify each one as work or private and add the reason.

• It warns you if you try to close the logbook before 12 weeks, because the ATO will not accept a shorter one.
• It reminds you when the 12 weeks are up to enter the closing odometer reading, and again a month before the logbook's five years run out.
• When you close it, it compares the odometer difference with the tracked kilometres and tells you how many were not tracked, so you can add the missing trips before you export.
• It exports the logbook as a CSV: the period, both odometer readings, total and business kilometres, the percentage, and one row per journey with its dates, kilometres, whether it was work and the reason.

One thing it does not do: read your dashboard. The opening and closing readings are the ones you type in. Each journey's odometer figures are calculated from the opening reading plus the GPS distance of every trip since, and the export labels them that way. If you want dashboard readings for every journey, note them as you go; either way, the untracked-kilometre check at the end is what tells you the log is complete. Exporting the logbook is part of TaxMiles Pro.

In Canada: a base year, then a three-month sample

The CRA works differently. A full logbook records the date, destination, purpose and kilometres of every business trip, plus the odometer at the start and end of the fiscal period. After one complete 12-month base year, you can keep a three-month sample logbook in later years, as long as the result stays within 10% of the base year. The CRA's formula is: sample period % ÷ base year same-period % × base year annual %. TaxMiles offers both the base year and the sample when your region is Canada; the CRA kilometre rates page explains why a self-employed Canadian needs the log.

Who this is not for

• Drivers under 5,000 business kilometres a year. The cents-per-kilometre method is simpler and needs no logbook.
• Employees whose employer reimburses the car. Check your employer's arrangement first; you may have nothing to claim.
• Anyone who will not classify trips. TaxMiles records every drive, but it cannot know which were for work unless you tell it.

Frequently asked questions

Do I need a new logbook every year?

No. The ATO says each logbook is valid for five years. You keep the logbook, and you keep odometer readings for the start and end of each income year you rely on it. Start a new one sooner if your work or driving changes.

Which 12 weeks should I pick?

Twelve continuous weeks that are representative of how you drive across the year. A quiet stretch, or your busiest, gives a percentage that does not describe the year.

Is writing business as the purpose enough?

No. The ATO says an entry of business or miscellaneous business will not be enough. The purpose should describe the trip well enough to show it was for work, for example deliveries for a named platform or a client visit to a named client.

What if I change cars during the logbook period or afterwards?

If you carry the business-use percentage over to a replacement car, the ATO asks for the odometer readings of both the old car and the new car on the day you replaced it.

Does TaxMiles read my odometer for each trip?

No. It records the readings you enter at the start and end of the period, and works out each journey's odometer figures from the opening reading plus the GPS distance of every trip. The export labels those figures as calculated. If you want dashboard readings for each journey, note them as you go.

Sources: the ATO's logbook method page and the CRA's motor vehicle records page. Checked 22 September 2026.

Related reading: ATO cents per km for 2026–27, mileage deductions in the UK, Canada and Australia, the odometer photo habit, and a 15-minute weekly log review.