How far back can HMRC ask for mileage records?
If you’re self-employed, GOV.UK says you must keep your records, including your mileage log, for at least 5 years after the 31 January submission deadline for the tax year they cover. If you’re an employee who sends a Self Assessment tax return, GOV.UK says to keep your records for at least 22 months after the end of the tax year.
This is record-keeping information, not tax advice. Check GOV.UK for your own situation, or ask an accountant.
HMRC may check your records to make sure you’re paying the right amount of tax (GOV.UK: Tax compliance checks). Here’s what GOV.UK says about how long to keep them, and how far back HMRC can look.
Self-employed: at least 5 years after the deadline
GOV.UK says: “You must keep your records for at least 5 years after the 31 January submission deadline of the relevant tax year.” Its example: if you sent your 2022 to 2023 tax return online by 31 January 2024, you must keep your records until at least the end of January 2029 (GOV.UK: Business records if you’re self-employed: how long to keep your records).
Applied to this year: the online deadline for the 2026–27 tax year is 31 January 2028, so a mileage log for 6 April 2026 to 5 April 2027 should be kept until at least the end of January 2033.
If you send a return very late, more than 4 years after the deadline, GOV.UK says to keep your records for 15 months after you send it.
Employees: it depends how you claim
If you send a Self Assessment tax return, GOV.UK says to keep your records for at least 22 months after the end of the tax year the return is for, or at least 15 months after you sent it if the return was late. Its example: a 2024 to 2025 return sent online by 31 January 2026 means keeping records until at least the end of January 2027 (GOV.UK: Keeping your pay and tax records: how long to keep your records).
If you claim Mileage Allowance Relief without Self Assessment, GOV.UK says you can claim for the current tax year and the 4 previous tax years, and you must send HMRC copies of your mileage logs showing the reason for every journey and the start and end postcodes (GOV.UK: Claim tax relief for your job expenses: vehicles you use for work). I couldn’t find a separate fixed retention period on GOV.UK for this route. In practice, if you might claim for earlier years, you need the logs for those years. See the Mileage Allowance Relief guide.
How far back HMRC can look
Keeping records and HMRC’s time limits aren’t the same thing. HMRC’s own manuals, published on GOV.UK, set out the limits for Self Assessment:
- Opening an enquiry: for a return sent on or before the filing date, HMRC can give notice of an enquiry up to 12 months from the date the return was delivered (GOV.UK: HMRC manual SALF403).
- Discovery assessments: after that, HMRC can normally make a discovery assessment up to 4 years after the end of the tax year. That extends to 6 years where a loss of tax was brought about carelessly, and 20 years where it was brought about deliberately (GOV.UK: HMRC manual SALF411).
These are HMRC’s internal manuals and the detail has exceptions, so ask an accountant if HMRC contacts you. Either way, an accurate log made at the time is what protects you.
If your records are lost
GOV.UK says that if you can’t replace your records, you must do your best to provide figures, and tell HMRC when you file if you’re using estimated or provisional figures (GOV.UK). HMRC can charge a penalty if your records are not accurate, complete and readable (GOV.UK).
Keeping a mileage log for years
- Save a copy of each tax year’s log as a file (CSV or PDF) once the year ends.
- Keep a second copy somewhere other than your phone or laptop.
- Name files by tax year, such as “mileage 2026-27”, so they’re easy to find.
Our free mileage log template works for paper or a spreadsheet. If you use Quidometer, exporting each tax year as a CSV or PDF gives you a copy to keep with your other records.
Questions
How long should I keep my mileage log if I’m self-employed?
GOV.UK says you must keep your records for at least 5 years after the 31 January submission deadline of the relevant tax year. For 2026–27, with a 31 January 2028 online deadline, that means until at least the end of January 2033.
How long should an employee keep mileage records?
If you send a Self Assessment return, GOV.UK says at least 22 months after the end of the tax year, or 15 months after you sent it if it was late. If you claim another way, you can claim for the current and 4 previous tax years, so keep logs for those years.
Can HMRC look back more than 5 years?
Yes, in some cases. HMRC’s manuals say a discovery assessment can normally be made up to 4 years after the end of the tax year, 6 years if a loss of tax was careless, and 20 years if it was deliberate.
What if I’ve lost my mileage records?
GOV.UK says to do your best to provide figures, and tell HMRC when you file if you’re using estimated or provisional figures. HMRC can charge a penalty if records are not accurate, complete and readable.