What should a mileage log include?
HMRC does not prescribe a form, but it expects a record of each business journey: the date, where you went from and to, why, and how far. If you are self-employed, keep it for at least five years after the Self Assessment deadline for that year. Employees can claim back four tax years, so keep records at least that long.
Updated 14 October 2026
The essentials for each journey
Date of the journey. Start point and destination. The business purpose: "site visit, Leeds client" rather than just "work". The miles driven. Many people also record the vehicle, which matters if you use more than one.
Totals by tax year (6 April to 5 April) let you apply the right rate: 55p for the first 10,000 business miles and 25p after, from 2026/27.
Why a contemporaneous log matters
A log written at the time is far more credible than one reconstructed from memory at the end of the year. If HMRC enquires into a claim, round numbers and identical weekly totals invite questions; a log that matches real journeys does not.
Odometer readings at the start and end of each tax year are a useful cross-check, and your car’s MOT mileage readings give an independent reference point too.
Paper, spreadsheet or app
Any of them is acceptable if it is complete and accurate. The weakness of paper and spreadsheets is that they depend on you remembering to fill them in, and the journeys you forget are lost money.
Odomint records every drive automatically in the background, with the route, distance and time. You tag each one business or personal, add any it missed by hand, and export a CSV with the claim worked out at the correct rate for each tax year.
How long to keep it
Self-employed: at least five years after the 31 January Self Assessment deadline for the tax year. Employees: a relief claim can reach back four tax years, so keep records at least that long. The safest habit is to keep the export alongside your tax records.
A sample entry
A good entry reads like this: 14 October 2026. Home, Croydon to Smith & Co, Guildford. Quarterly review. 31.2 miles. Business. The return journey is a separate entry, or recorded as a round trip with the total. Each line answers when, where, why and how far.
Keep personal journeys in the log too, marked as personal. A record of every journey with each one tagged is more credible than a list containing only business trips, and it lets you show the split between business and private use if you are claiming actual costs rather than the flat rate.
Common questions
Does HMRC require a specific mileage log format?
No. Any format is acceptable if it records the date, journey, business purpose and miles for each trip.
How long should I keep mileage records?
At least five years after the Self Assessment deadline if self-employed. Employees can claim back four tax years, so should keep records at least that long.
Can I use an app for my HMRC mileage log?
Yes. An app log is acceptable as long as it is accurate and includes the purpose of each business journey.
Check any car before you buy it
MOT history, every advisory and the full mileage record are free for any UK registration. An Odomint Check adds outstanding finance, insurance write-offs, stolen markers and salvage history, with a £10,000 data guarantee.