ATO Car Log Book Requirements

You have to follow specific requirements for your car log book depending on the reimbursement or deduction method you use.

The records you need to keep for your car log book depend on which ATO method you use to claim your work-related car expenses. There are three options: the logbook method, the actual costs method, and the cents per kilometre method. Each has different requirements for what you record, how long you keep records, and what supporting documents you need.

If you drive your personal vehicle for work, you may receive reimbursement from your employer or claim a tax deduction from the ATO. Either way, a car log book is how you prove the kilometres you've driven and the expenses associated with running your vehicle.

What is a car log book?

If you drive your personal vehicle for work, you might receive business-related car expenses reimbursement if you are employed, or claim a tax deduction from the ATO as an employee, self-employed, or company.

In order to prove the kilometres you’ve driven and the expenses associated with owning and operating your car, you need to have records - a car log book, also known as a vehicle log book.

The ATO also has rules that apply if you are claiming a tax deduction on your work-related car expenses.

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ATO logbook method requirements

The logbook method lets you claim the actual business-use percentage of your car expenses, with no cap on the kilometres you can claim. It requires more detailed record-keeping than the cents per kilometre method, but it's the better option if you drive a lot for work.

How long is a logbook valid for?

You must keep track of your business and personal driving for a minimum of 12 weeks. The kilometres logged can be extrapolated to cover the rest of the year (assuming that your driving will remain similar). You can use the same logbook for the next 5 years of your tax claims, and you can start a new car log book at any time.

This 12-week period can take place at any time throughout the financial year - and if your car expenses fluctuate month-to-month, recording your kilometres and expenses year-round is a clever way to ensure that you maximise your tax deduction by accounting for all expenses and prioritising peak months.

What to record in your log book

• General information
  • The period of time being tracked
  • Odometer readings at the beginning and end of the period
  • The total kilometres driven
  • The percentage of kilometres travelled for business
• Information required for each trip logged:
  • Start date
  • End date
  • Total distance travelled
  • Odometer readings at the start and end of each trip
  • Reason for the journey

You also need to keep all receipts and invoices for car expenses incurred throughout the year, such as fuel, servicing, repairs, insurance, and registration. Your deduction is calculated by applying your business-use percentage to the total of these expenses.

Important: The logbook method can only be used to claim expenses for a car you own. You'll also need evidence of ownership, and depreciation can be included as part of your claim. See our article on claiming vehicle depreciation for more detail.

Actual costs method logbook requirements

The actual costs method requires you to record all driving throughout the entire year, not just a 12-week sample. This is the key difference from the logbook method. Because your business-use percentage is based on 12 months of data rather than an extrapolated sample, the record-keeping commitment is higher.

To submit a claim using the actual costs method, you need:

• A complete record of all kilometres driven for business and personal purposes across the full year, including all the trip details listed above for the logbook method
• All receipts and invoices for car running costs, including fuel, repairs, and servicing
• Loan or lease documents and your vehicle registration papers
• A clear explanation of how you calculated your claim

As with the logbook method, the actual costs method is only available for a car you own.

The cents per kilometre method requirements

The cents per kilometre method has the simplest record-keeping requirements of the three. The ATO rate for 2025/26 is 88 cents per km, unchanged from the previous year. You can claim up to a maximum of 5,000 business kilometres per car per year using this method.

Because the rate already accounts for all running costs, including fuel, insurance, servicing, registration, and depreciation, you cannot claim any of those expenses separately.

What you need to record:

• The total kilometres driven for business purposes
• The percentage of kilometres driven for business

You don't need written evidence for each trip, but the ATO may ask you to show how you worked out your business kilometres. A diary, calendar entries, or a logbook app are all accepted ways of demonstrating this.

If you use the cents per kilometre method to claim a tax deduction (rather than for employer reimbursement), you'll also need to show evidence that you own the vehicle, since the rate covers depreciation as part of the all-inclusive amount.

Car log book formats

The ATO accepts log books in any of the following formats:

• Paper diary or account book
• Digital spreadsheet (Excel, Google Sheets)
• CSV or PDF file
• A dedicated logbook app

The format doesn't matter as long as the required information is present. Most logbook apps let you export your records in multiple formats, which makes it straightforward to share them with your employer or accountant.

The ATO provides its own digital logbook tool, but it doesn't include automatic trip tracking. Paper logbooks are available from newsagents and work well for the logbook method, provided you fill them in at the start and end of each trip.

If you'd prefer not to log trips manually, an automated car log book app can track your trips in the background and generate ATO-compliant reports in PDF or Excel. You can also download a free ATO-compliant log book template in PDF or Excel to get started.

If you're submitting records to your employer, check with them first about which format they can process.

Keeping records and ATO audits

Keep your car log books for five years from the date you lodge your tax return. This is the standard ATO retention requirement, and it applies regardless of which method you use.

If the ATO audits your claim, they can ask to see:

• Your km log book (in any of the accepted formats above)
• Tax invoices or receipts for car expenses claimed
• Evidence of car ownership, if you used the logbook or cents per km method for a tax deduction

To make an audit straightforward, it helps to organise your records by financial year. A logbook app like Driversnote stores all your trip data automatically, so your records are always complete and easy to export, even years after the fact.

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