HMRC Mileage Allowance Calculator

What this calculator does

It values your business mileage at HMRC's approved rates, for the tax year you choose. If you are an employee using your own vehicle, it also compares that figure with what your employer paid you and shows the Mileage Allowance Relief you can claim on a shortfall, or the taxable excess if you were overpaid. If you are self-employed, it shows the simplified-expenses deduction and the Income Tax it saves.

The approved rates

For the 2026/27 tax year, cars and vans are 55p a mile for the first 10,000 business miles and 25p after that. Motorcycles are 24p a mile and bicycles 20p a mile, with no 10,000-mile step (gov.uk). The 55p rate was backdated to 6 April 2026; before that, the first 10,000 miles were 45p. The 10,000 miles are counted over the whole tax year, so the calculator lets you enter miles already claimed.

If you are an employee

Your employer can pay you the approved amount tax-free without reporting it. If they pay less than the approved amount, you can claim tax relief, called Mileage Allowance Relief, on the unused balance. If they pay more, the excess goes on a P11D and is taxed. Business journeys exclude travel to and from your usual place of work, unless it is a temporary workplace. You can claim for the current tax year and the four previous ones.

Keep a mileage log

HMRC expects you to keep the dates and mileage of your work journeys. When you claim you send the logs, with the reason for each journey and the start and end postcodes. Do not include anything your employer has already paid you for those costs.

If you are self-employed

Simplified expenses use the same rates for cars, goods vehicles and motorcycles, but there is no flat rate for bicycles when you are self-employed. You cannot use the flat rate for a vehicle you have claimed capital allowances on. Once you use it for a vehicle you must keep using it for as long as you use that vehicle for the business. Parking and train fares can be claimed on top.

Passengers and National Insurance

An employer can pay up to 5p a mile tax-free for each employee carried as a passenger on a business journey. For National Insurance purposes the employer's rate for cars is 55p for all business miles, not just the first 10,000, so the two schemes diverge above 10,000 miles.

A worked example

An employee drives 12,000 business miles in 2026/27. The approved amount is 10,000 miles at 55p plus 2,000 at 25p, which is £6,000. If the employer paid £4,000, the shortfall is £2,000, and at the 20% basic rate the tax relief is £400. A self-employed driver with the same miles deducts £6,000, saving £1,200 of Income Tax at 20%.

What this calculator does not cover

It does not model Class 4 National Insurance on the self-employed deduction, passenger payments, company car fuel or electric vehicles beyond treating them as a car. If you are self-employed, the driver calculator compares the flat rate against your real costs. It is an estimate, not advice.