Mileage Tax Relief Calculator, 2026/27

How this is calculated

This tool first works out the full AMAP entitlement for your business mileage: £0.55 per mile for the first 10,000 miles and £0.25 per mile after that. It then compares this to what your employer actually pays per mile, and the difference is the unused allowance.

Unlike the employer's tax-free payment, mileage allowance relief is not paid out in full. HMRC gives relief at your marginal rate of income tax on the shortfall, so a higher rate taxpayer recovers 40% of the gap and a basic rate taxpayer recovers 20%.

This is a different calculation from the mileage allowance calculator elsewhere on this site, which simply shows what an employer can pay tax-free. This one is aimed at the employee working out what they can personally reclaim from HMRC.

How to claim

Claims of £2,500 or less are usually made using form P87, either online or by post, and can typically be backdated up to four tax years. Larger claims, or claimants who already complete a self-assessment return, should include the figure on the employment pages instead.

You will need your employer's PAYE reference, a record of business miles travelled and the rate your employer actually reimbursed, which is normally shown on payslips or an expenses report.

Common situations

Many employers pay a flat rate, such as 20p or 25p per mile, well below the 45p AMAP rate, particularly for mileage between multiple client sites. Some pay nothing at all and expect the employee to claim relief directly.

Where an employer pays above the AMAP rate, there is no relief to claim; instead the excess is added to taxable pay and should already appear on the P11D or payslip.

How far back can I claim mileage tax relief?

HMRC generally allows claims for the past four tax years, so a claim made in the 2026/27 tax year can usually reach back to 2022/23, provided you can still evidence the mileage and the rate paid.

What if my employer pays nothing towards mileage?

You can still claim relief on the full AMAP entitlement at your marginal rate, since the whole amount is then an unused allowance rather than a partial shortfall.

Do I need a mileage log to claim?

Yes. HMRC can ask for evidence of business journeys, so keep a record of dates, destinations, purpose and miles travelled, ideally alongside your employer's mileage reimbursement statements.

Is mileage relief the same as claiming fuel costs?

No. The AMAP rate already bundles fuel, insurance, servicing, depreciation and other running costs into a single mileage rate, so you cannot separately claim actual fuel receipts on top.