Fuel Cost Per Mile (UK)

The formula

Cost per mile = (4.54609 ÷ MPG) × price per litre in pounds × 100. The 4.54609 is the number of litres in an imperial gallon; without it you get a US-gallon answer that is about 20% too low.

At 45 MPG and 145.9p a litre, one mile costs 14.7p. At 30 MPG it is 22.1p. At 60 MPG it is 11.1p.

Pence per mile by MPG (petrol at 145.9p/litre)

HMRC mileage rates vs actual fuel cost

HMRC's approved mileage allowance is 45p per mile for the first 10,000 business miles in a car or van, then 25p. That rate is designed to cover fuel, wear, insurance and depreciation — not just fuel. If you are only claiming fuel, use the real cost above (typically 12–26p a mile); if you are reimbursing a driver for the whole vehicle, the 45p rate is usually the fairer number.

Petrol, diesel and EV side by side

Where cost per mile is used

• Pricing jobs and deliveries — add pence per mile to labour to avoid losing money on travel.
• Choosing a car — a car that does 55 MPG instead of 40 saves about £330 per 10,000 miles at today's prices.
• Expenses and mileage claims — the real fuel cost is the defensible figure when an employer reimburses fuel only.
• Comparing a commute — 20 miles each way, 45 MPG, is about £5.90 a day in petrol.

Common questions

How do I work out pence per mile?

Divide 4.54609 by your MPG, multiply by the price per litre in pounds, then multiply by 100. At 45 MPG and 145.9p a litre that is 14.7p per mile.

Is 45p per mile enough to cover fuel?

The HMRC 45p rate covers far more than fuel — it includes wear, insurance and depreciation. Actual fuel at 45 MPG is around 15p a mile.

Does cost per mile include servicing and tyres?

No. This calculator is fuel only. Add roughly 8–12p a mile for servicing, tyres and depreciation on a typical car.