A petrol car doing 45 miles to the gallon costs 14.6p a mile in fuel at £1.45 a litre, which is £1,465 over 10,000 miles. At 30 mpg the same mileage costs £2,197 and at 60 mpg £1,099. An electric car managing 3.5 miles per kWh costs 7.5p a mile on the October 2026 price cap rate of 26.32p, 2p a mile on a 7p overnight tariff and about 22.6p a mile from a 79p rapid charger. Where and when a car is refuelled therefore matters as much as what it is.
Fuel cost per mile by economy
| Fuel economy | Cost per mile at £1.45 a litre | 10,000 miles a year |
|---|---|---|
| 30 mpg | 22.0p | £2,197 |
| 40 mpg | 16.5p | £1,648 |
| 45 mpg | 14.6p | £1,465 |
| 50 mpg | 13.2p | £1,318 |
| 60 mpg | 11.0p | £1,099 |
The arithmetic is price per litre multiplied by 4.546 litres to the gallon, divided by miles per gallon. A litre price of £1.35 brings the 45 mpg car to 13.6p a mile and £1,364 a year; £1.55 takes it to 15.7p and £1,566, so a 20p swing in pump prices moves the annual bill by about £200 for an average driver. Real-world economy is usually 10% to 20% below the official figure, and short urban journeys from cold can halve it. The fuel cost calculator works the figure for any mileage, economy and price, and the MPG calculator turns a tankful and a mileage into your actual figure: 400 miles on 40 litres is 45.5 mpg and 14.5p a mile.
Electric car charging cost per mile
| Where the car is charged | Price per kWh | Cost per mile at 3.5 miles per kWh | 10,000 miles a year | Charging a 60 kWh battery from 20% to 80% |
|---|---|---|---|---|
| Home, standard tariff at the October 2026 cap | 26.32p | 7.5p | £752 | £9.48 |
| Home, overnight EV tariff | 7p | 2.0p | £200 | £2.52 |
| Public rapid charger | 79p | 22.6p | £2,257 | £28.44 |
A 60 kWh car at 3.5 miles per kWh has a real range of about 210 miles, and a 20% to 80% top-up adds 36 kWh. Charged at home on an off-peak tariff the running cost is a tenth of a 45 mpg petrol car’s; charged only at rapid chargers it costs more than the petrol car. Most owners with a driveway do the large majority of charging at home, so the blended figure sits nearer the top of the table than the bottom. The EV charging cost calculator uses your own battery size, tariff and efficiency, and the electric versus petrol calculator adds tax, servicing and depreciation to the fuel difference. Our energy price cap guide explains the 26.32p unit rate and the zero VAT on electricity from 1 October 2026.
What the fuel figure leaves out
Fuel is a minority of the cost of running a car. Depreciation on a new car is usually the largest item, followed by insurance, then fuel, then servicing, tyres and tax. The approved mileage rate for using your own car for work is 55p a mile for the first 10,000 business miles, of which the 14.6p fuel element is about a quarter; the rest is the allowance for everything else. Our mileage allowance guide covers the rate and how to claim the shortfall when an employer pays less, and the cost of ownership calculator builds the full per-mile figure for a specific car.
Cutting the bill
Fuel duty and VAT make up roughly half the pump price, so supermarket forecourts, which typically undercut motorway services by 15p to 20p a litre, are the largest single saving available to a petrol or diesel driver. Beyond that, correct tyre pressures, removing roof boxes, keeping to 60 to 65 mph on motorways and avoiding short cold-start trips each improve economy by a few per cent. For electric cars the equivalent is moving to a time-of-use tariff and scheduling charging into the overnight window, which cuts the per-mile cost by around three quarters compared with the standard rate. The road trip cost calculator splits the fuel or charging cost of a specific journey between passengers.
Common questions
How much does petrol cost per mile? About 14.6p at 45 mpg and £1.45 a litre, 22p at 30 mpg and 11p at 60 mpg. Multiply the litre price by 4.546 and divide by your mpg.
How much does it cost to drive 10,000 miles a year? Between £1,100 and £2,200 in fuel for a petrol or diesel car at 60 to 30 mpg and £1.45 a litre. An electric car charged at home costs £200 to £750 for the same distance.
Is an electric car cheaper to run? Per mile, yes when charged at home: 7.5p on the standard tariff and 2p overnight against 14.6p for a 45 mpg petrol car. Rapid charging at 79p per kWh costs more than petrol.
How much does it cost to charge an electric car at home? About £9.48 to add 36 kWh, a 20% to 80% charge on a 60 kWh battery, at the 26.32p cap rate, or £2.52 on a 7p overnight tariff.
What is a good mpg? Above 50 mpg is good for a petrol car in real-world driving; small diesels and hybrids can exceed 60. Large petrol SUVs often return under 30.
Why is my real mpg lower than the official figure? Official tests run in controlled conditions. Cold starts, short trips, town driving, air conditioning and roof loads all reduce economy, typically by 10% to 20%.
Information, not financial advice. Figures are from the site’s calculators at an illustrative £1.45 a litre and 3.5 miles per kWh; the 26.32p electricity rate is the Ofgem price cap direct debit average for October to December 2026, and public charging prices vary by network. Check current pump and tariff prices before acting on them.