If you're self-employed and claiming mileage as a business expense, HMRC requires you to keep proper records of your journeys.
Many drivers claim mileage deductions but don't keep detailed logs. If HMRC ever reviews your tax return, poor record keeping could mean losing the deduction entirely.
Here's what HMRC expects when you claim mileage.
Why Mileage Records Matter
When you claim the simplified mileage method, HMRC allows:
- 45p per mile for the first 10,000 miles
- 25p per mile after that
These rates cover costs like fuel, insurance, servicing and vehicle wear.
However, you must be able to prove that the miles were driven for business purposes.
That's why keeping accurate records is important.
What HMRC Requires in a Mileage Log
HMRC does not prescribe a specific format, but your records should include the following details for each journey.
1. The Date of the Journey
Each trip should include the date it took place.
Example: Start mileage: 42,115 End mileage: 42,158 Distance: 43 miles
Do You Need to Record Every Trip?
Ideally, yes.
Recording journeys as they happen creates the most reliable log and avoids errors later.
Some people try to estimate mileage months later using maps or delivery history. While this can sometimes work, it is less reliable and harder to defend during an HMRC enquiry.
How Long Should You Keep Mileage Records?
HMRC requires self-employed individuals to keep records for at least 5 years after the 31 January submission deadline for the relevant tax year.
For example:
- Tax year: 2025–2026
- Filing deadline: 31 January 2027
- Records must be kept until 31 January 2032
Common Mistakes Drivers Make
Many drivers accidentally weaken their mileage claims by:
- estimating miles instead of recording them
- keeping incomplete logs
- mixing personal and business travel
- losing records during the year
Good record keeping avoids these issues and makes tax filing much easier.
Using Technology to Track Mileage
Many self-employed drivers now use apps to automatically track mileage.
Instead of manually recording journeys, an app can:
- track trips automatically
- calculate total business miles
- store mileage logs securely
- generate reports for tax returns
This can make it much easier to keep records that satisfy HMRC requirements.
The Bottom Line
Mileage deductions can significantly reduce your taxable profit, but only if you maintain accurate and reliable records.
Keeping a consistent mileage log ensures you can confidently claim the deduction and stay compliant with HMRC rules.