Published: 4 March 2026 | FY 2025-26

Logbook Method Calculator: Maximise Your Car Expense Tax Deductions

If you use your personal vehicle for work-related travel, the logbook method could be your ticket to significantly larger tax deductions. While the cents per kilometre method offers simplicity, the logbook method often delivers bigger refunds for Australian workers who rely heavily on their cars for business purposes. Understanding how this method works, what records you need to keep, and how to calculate your deductions correctly can make a substantial difference to your tax outcome.

The Australian Taxation Office (ATO) provides two approved methods for claiming work-related car expenses, and choosing the right one is crucial for maximising your legitimate tax benefits. For the 2025-26 financial year, many Australian workers—from tradies and sales representatives to healthcare professionals and consultants—could be leaving money on the table by not using the logbook method. This comprehensive guide will walk you through everything you need to know about calculating and claiming car expenses using the logbook method.

What Is the Logbook Method?

The logbook method is an ATO-approved approach for calculating work-related car expense deductions based on the actual percentage of business use of your vehicle. Unlike the cents per kilometre method, which uses a flat rate, the logbook method calculates your deduction as a percentage of your total vehicle running costs. This can result in significantly higher deductions if you use your car extensively for work purposes or if your vehicle has higher-than-average running costs.

Under this method, you maintain a detailed logbook for a continuous 12-week period that accurately represents your typical travel patterns throughout the year. This logbook establishes your work-related use percentage, which is then applied to all your vehicle expenses—including fuel, registration, insurance, servicing, repairs, depreciation, and even interest on your car loan. The result is a precise, evidence-based deduction that reflects your actual work-related vehicle usage.

How the Logbook Method Works

The logbook method follows a straightforward but structured process that ensures your deductions are accurate and ATO-compliant. First, you maintain a valid logbook for 12 continuous weeks, recording every journey—both work-related and personal. From this data, you calculate your business use percentage by dividing work kilometres by total kilometres travelled during the logbook period.

Once you have your business use percentage, you apply it to all your vehicle expenses for the year. For example, if your logbook shows 60% business use and your total vehicle expenses are $15,000, your deduction would be $9,000. This is significantly higher than the maximum $4,400 you could claim using the cents per kilometre method, demonstrating why the logbook method is often more beneficial for workers with substantial work-related travel.

Your logbook remains valid for five years, provided your work-related travel pattern doesn't change significantly. This means you don't need to complete a new logbook every year—though you must keep odometer readings at the start and end of each financial year to calculate total kilometres travelled.

What Expenses Can You Claim Under the Logbook Method?

One of the major advantages of the logbook method is the comprehensive range of vehicle expenses you can claim. Unlike the cents per kilometre method, which bundles everything into a single rate, the logbook method allows you to claim actual costs across multiple categories. This typically results in a more accurate and often larger deduction.

The following table outlines the expenses you can claim and their typical record-keeping requirements:

For depreciation purposes, the ATO allows you to claim the decline in value of your vehicle over its effective life. If you purchased your car for more than the luxury car depreciation limit ($69,466 for 2025-26), your depreciation claim is capped at this amount. Understanding these limits and keeping accurate records ensures you claim the maximum legitimate deduction while remaining compliant with ATO requirements.

Keeping a Valid Logbook: ATO Requirements

The ATO has specific requirements for what constitutes a valid logbook, and failing to meet these requirements could result in your deductions being disallowed. Your logbook must be kept for a continuous period of at least 12 weeks, and it must represent your typical travel patterns throughout the year. If you have multiple vehicles, you need a separate logbook for each one.

For each journey in your logbook, you must record the following details: the date of the journey, the odometer readings at the start and end, the total kilometres travelled, the purpose of the journey, and whether it was work-related or private. You don't need to record every single private trip—just enough to establish the total private kilometres for the period. However, you must record every work-related journey in detail.

Many Australian workers find that using a dedicated logbook app on their smartphone makes record-keeping much easier. These apps can automatically track GPS data, calculate distances, and export reports in formats suitable for tax purposes. Whether you use an app or a physical logbook, the key is consistency and accuracy. Start your logbook at the beginning of any 12-week period, and make sure it covers your typical work activities.

Logbook Method vs. Cents Per Kilometre: Which Is Better?

Choosing between the logbook method and the cents per kilometre method depends on your individual circumstances. The cents per kilometre method is simpler and requires less record-keeping—you just claim 88 cents per kilometre for up to 5,000 work-related kilometres, giving you a maximum deduction of $4,400. This method is ideal if you have moderate work travel and want to minimise paperwork.

However, if your work-related travel exceeds approximately 5,000 kilometres per year, or if you have a vehicle with high running costs, the logbook method will almost certainly deliver a better tax outcome. For example, if you drive 15,000 kilometres for work with total vehicle costs of $20,000, and your logbook shows 50% business use, your deduction would be $10,000—more than double the maximum cents per kilometre claim.

The following comparison table helps you decide which method suits your situation:

Remember, you can switch methods from year to year based on what works best for your situation. However, you cannot use both methods for the same vehicle in the same financial year—you must choose one method per vehicle. Consider using our income tax calculator to see how different deduction scenarios might affect your overall tax position.

Calculating Your Work-Related Percentage

The key to the logbook method is accurately calculating your work-related percentage. This is done by dividing your work-related kilometres by your total kilometres travelled during the logbook period, then multiplying by 100. For example, if you travelled 8,000 kilometres total and 3,200 were for work, your work-related percentage is 40%.

It's important to understand what constitutes work-related travel under ATO rules. Deductible work travel includes trips between different workplaces, travel from your home to an alternative workplace (such as a client's office), travel between job sites, and trips to collect supplies or equipment. If you carry bulky tools or equipment that your employer requires and there's no secure storage at your regular workplace, travel from home may also be deductible.

However, ordinary travel between your home and regular workplace is considered private and cannot be claimed. Similarly, detours for personal errands, travel during unpaid meal breaks, and travel after work for personal purposes are not deductible. Being precise about these distinctions ensures your claim is accurate and defensible if the ATO asks questions.

Impact on Your Tax and Other Financial Obligations

Claiming car expenses through the logbook method can have meaningful flow-on effects for your overall tax position. Because deductions reduce your taxable income, they also affect your Medicare levy calculation, as the 2% levy is applied to your taxable income after deductions. For higher income earners, reducing taxable income through legitimate deductions may also help you avoid the Medicare Levy Surcharge.

However, it's important to understand that tax deductions don't reduce your repayment income for HECS-HELP purposes. The ATO adds back certain deductions when calculating your HECS repayment income, which is used to determine your compulsory HELP repayments. Similarly, if you're considering salary sacrifice arrangements, remember that these don't reduce your HECS repayment income either.

Your superannuation contributions are also affected by your taxable income. If you're making personal deductible super contributions, these are claimed as a deduction on your tax return, reducing your taxable income further. However, remember that concessional contributions are capped at $30,000 for the 2025-26 financial year, including employer contributions and any salary sacrifice amounts.

To get a complete picture of how car expense deductions fit into your overall financial situation, use our take-home pay calculator. This tool helps you estimate your net income after accounting for income tax, Medicare levy, superannuation, and other deductions, giving you a clearer understanding of your true financial position.

Tips for Maximising Your Logbook Deductions

To get the most from the logbook method, start by planning your 12-week logbook period carefully. Choose a time that truly represents your typical work patterns—avoid periods when you're on annual leave, working from home more than usual, or covering for colleagues in different locations. The more representative your logbook period, the more accurate your deduction percentage will be.

Keep all your vehicle expense receipts organised throughout the year. Create a dedicated folder (physical or digital) for car-related expenses including fuel, servicing, registration, and insurance. Many Australian workers miss legitimate deductions simply because they lost receipts or forgot to claim expenses they incurred. Consider using a receipt scanning app to digitise and categorise your expenses as you go.

If you use your vehicle for both work and personal purposes, consider the timing of major expenses. If you need expensive repairs or new tyres, and your work-related percentage is high, these costs will significantly boost your deduction. While you shouldn't delay necessary maintenance for tax reasons, being aware of these timing considerations can help you plan major expenses strategically.

Common Mistakes to Avoid

Many Australian workers make errors when using the logbook method that can lead to reduced deductions or ATO scrutiny. One common mistake is not keeping a logbook for the full 12 continuous weeks—a partial logbook is not valid and cannot be used to establish your work-related percentage. Another error is claiming travel between home and your regular workplace as work-related travel, which is specifically excluded by the ATO.

Other mistakes include claiming expenses for a vehicle provided by your employer, not keeping receipts for all claimed expenses, failing to record odometer readings at the start and end of each financial year, and using an outdated logbook when your work travel patterns have changed significantly. If your job changes or your work-related travel increases or decreases substantially, you should start a new 12-week logbook period.

Some taxpayers also make the error of claiming depreciation on a vehicle that has already been fully depreciated, or claiming interest on a loan that has been paid off. Always ensure your expense claims are current and accurate. If you're unsure about any aspect of your claim, consider consulting a registered tax agent—whose fees are themselves tax deductible.

Summary: Making the Logbook Method Work for You

The logbook method is a powerful tool for Australian workers who use their personal vehicles extensively for work purposes. While it requires more record-keeping than the cents per kilometre method, the potential tax benefits can be substantial—often thousands of dollars more in deductions for those with significant work-related travel. For the 2025-26 financial year, understanding and properly implementing the logbook method could make a real difference to your tax refund.

The key to success is maintaining accurate records throughout the year, understanding what constitutes legitimate work-related travel, and applying your work-use percentage correctly to all vehicle expenses. Remember that your logbook is valid for five years, so the effort you put into maintaining it pays dividends across multiple tax returns. Keep all receipts, record your odometer readings, and stay organised.

Whether you're a tradie travelling between job sites, a sales rep visiting clients, a healthcare worker making home visits, or any other professional who relies on their vehicle for work, the logbook method could significantly improve your tax outcome. Take the time to understand the requirements, keep proper records, and claim every legitimate deduction you're entitled to. Your future self—and your bank account—will thank you at tax time.