This is general guidance, not personalised tax advice. ATO rates and thresholds change — check ato.gov.au or your accountant for current figures.
Vehicle costs are one of the largest expenses a tradie carries, and one of the least accurately tracked. Most reconstruct a rough kilometre figure at tax time from memory, or don't claim vehicle costs properly at all because building a logbook after the fact feels pointless. Neither serves you well — the ATO expects contemporaneous records, and under-claiming a legitimate cost is money left on the table.
Two ways to claim vehicle costs
- Cents-per-kilometre method — a set rate per business kilometre (the ATO updates it each year), capped at 5,000 business kilometres annually. Simple, no receipts needed for running costs, but capped.
- Logbook method — a 12-week sample logbook establishes your business-use percentage, then applied to actual running costs (fuel, insurance, servicing, depreciation) for the full year. More upfront effort, but can capture a much bigger claim for high business use.
Whichever method, a record of business trips is expected — the cents-per-kilometre method still requires you to show a reasonable basis for the kilometres claimed.
What a proper logbook needs
- Date of the journey
- Start and end odometer readings or distance
- Purpose of the trip — which job it relates to
- A 12-week continuous sample period, representative of your normal travel pattern
Tying each trip to a specific job is where most mileage apps fall short. A generic tracker gives you a yearly total for the ATO. It doesn't tell you that one job needed five extra site visits that quietly ate into its margin.
Why job-level mileage matters, not just the yearly total
A job that needed multiple site visits and extra supplier runs costs more in vehicle time and fuel than one finished in a single trip — but if kilometres aren't tagged to the job, that cost is invisible until the year's fuel bill is totalled up. Tracking mileage per job shows which jobs are quietly more expensive to run, not just what the total deduction comes to.
Spreadsheet vs app
| Method | What actually happens |
|---|---|
| Memory, reconstructed later | Rough estimate, rarely accurate, doesn't survive an ATO review. |
| Paper logbook | Accurate if kept up for the full 12 weeks, usually abandoned within a fortnight. |
| Spreadsheet | Works if you log every trip same-day — most people don't. |
| App logging trips per job (like Site Wallet) | A trip logged in seconds, tagged to the job it was for, rolled into that job's real cost. |
How Site Wallet handles vehicle costs
Mileage and fuel receipts tag to a job exactly like any other cost, so a job's running total includes what it actually cost to get there and back — not just materials and labour. At tax time, export the same records for whichever method you or your accountant use to calculate the vehicle claim.
FAQ
Can I use the cents-per-kilometre method one year and a logbook the next?
Yes — you can choose whichever method suits you each year, though switching to the logbook method requires a fresh 12-week logbook to establish your business-use percentage.
Do I need to log personal trips too?
For the logbook method, yes — the logbook needs to reflect both business and personal use during the sample period to establish an accurate percentage.
What if I've been estimating my kilometres for years?
Going forward, log every business trip as it happens — a defensible, contemporaneous logbook from today onward is far stronger than trying to fix historic estimates retroactively.