Car running cost calculator: what a car really costs
Everyone budgets for the car. Almost nobody budgets for the year that follows it. Put your own numbers in below and the year appears: what it costs a month, what it costs a mile, and which line is quietly eating the money. It will not be the petrol.
On a realistic first year, keeping a car on the road costs about £3,226. That is £269 a month, or 64.5p for every mile you drive. Insurance is over half of it. Petrol is a quarter. Those are the settings the boxes start with, and they are all yours to change.
A first car often does 4,000 to 6,000. Your yearly MOT certificate shows your real mileage.
Small petrol cars are usually 40 to 55 in real life. The brochure number is always higher than yours.
161.6p is the UK average for the week to 24 August 2026. Look at the sign on your nearest forecourt.
£1,695 is the average comprehensive premium at 17. Get a real quote for the exact car before you buy it.
£200 is the standard rate. Older and smaller cars can be less, so check the exact car and year.
£515 is the MOT at £54.85, about £400 of servicing and repairs, and £60 of odds and ends. Older cars cost more.
Leave it at zero if the car is already yours. If you are borrowing to buy it, this is the payment.
Why the petrol is not the problem
Start it up on the default settings and one line towers over the rest. Insurance is 2.1 times what the fuel costs.
That matters because of what people do about it. The instinct, when a car feels expensive, is to drive less. Driving less saves you petrol, and petrol is about a quarter of the bill.
The other three quarters happen whether the car moves or not. Insurance, road tax, the MOT, the service: those are the price of the car existing, parked outside, doing nothing.
So a car sitting on a drive for a month still costs you roughly £200. Which is worth knowing before you buy one for a job you could walk to.
And if the big line is insurance, the big lever is insurance. The insurance page has the method: what actually moves a premium at 17, and the one that is a criminal offence.
The number nobody quotes
Cars are sold to you by the month. Never by the mile.
On the defaults, every mile you drive costs 64.5p once everything is counted. A ten mile round trip is £6.45. Running a mate home is not free. It was just paid for in advance, in a payment that arrives whether you drive or not.
None of that means do not drive. It means that when you compare a car to a bus fare, a train ticket or a lift, the number to compare is the one per mile, not the petrol you put in on Tuesday.
Every single part of buying a car is priced by the month. The finance is a monthly payment. The insurance is offered monthly. Breakdown cover, monthly.
Monthly is a brilliant unit for selling things, because it makes every number small enough to say yes to, and it hides how they stack.
The year is the honest unit for the cost. The mile is the honest unit for the decision. Nobody is ever going to sell you a car per mile, which is exactly why it is worth working out yourself.
And note what happens when you put the insurance on monthly instalments. That is credit, at an APR, on the thing that was already the biggest line.
What this does not include
Being clear about the holes matters more than making the number look impressive.
Depreciation. The car is worth less every year you own it, and that loss is real money. It is not in here because it depends entirely on what you bought and what happens to it.
Buying the car in the first place. This is running costs only. Your first car has the whole picture, learning to drive included, and it comes to £7,145.
Parking, tolls, cleaning and fines. Small individually. Not small in a year.
So treat the answer as the floor, not the ceiling. It is the least a car can cost you, with everything going right.
- Get a real insurance quote before you choose the car, not after. Two cars that cost the same to buy can be hundreds apart to insure, and you only find out by asking.
- Look up the road tax band for the exact car and year, not the model in general. It is free to check and it is a different number for almost every car.
- Find the real MPG for that car from people who own one, then take a little off. Nobody gets the brochure figure.
- Check today's petrol price at the garage you would actually use and put that in the box.
- Write the yearly figure down somewhere you will see it. The monthly number is the one that gets quoted at you. The yearly one is the one that is true.
- Work out the per mile cost for the trips you actually make and put it next to a bus fare. Not to talk you out of a car. To make it a comparison instead of a habit.
- Run it again with the finance box filled in before you agree to anything, so you see the whole monthly commitment in one number.
The fuel maths. An imperial gallon is 4.54609 litres, so litres used equals miles divided by miles per gallon, times 4.54609. Litres times the pence price, divided by 100, is the pounds. Nothing else in the sum is more complicated than adding up.
Petrol at 161.6p a litre is the UK average for the week to 24 August 2026, the same figure used on your first car.
Insurance at £1,695 is the average comprehensive premium for a 17 year old from the Confused.com price index, also carried on the first car page. It is an average, so plenty of real quotes are higher.
Road tax at £200 is the standard annual rate, and the MOT cap is £54.85 for a car. Both are published by the government and both are checkable in a minute.
The £515 servicing default is the £54.85 MOT plus about £400 of servicing and repairs plus £60 of odds and ends, matching the first car page.
The two pages agree, and that is checked. At 5,000 miles and 45 miles per gallon this calculator produces exactly the £816 of fuel printed on the first car page. If one ever moves without the other, the build fails.
Nothing you type here goes anywhere. The sums run in your own browser. There is no account, no server and no storage, and the build refuses to publish this page if the code contains anything that sends or saves what you type.
Questions people ask
How much does it cost to run a car in the UK at 17?
On the settings this page starts with, about £3,226 a year, or £269 a month, for a car you already own. Insurance is over half of that. Change the boxes to your own mileage, car and quote and the answer changes with them.
Why is the insurance more than the petrol?
Because insurance is priced on risk, and a 17 year old is the highest risk group on the road. Fuel is priced on distance, and a first car does not do many miles. At 5,000 miles a year the insurance comes to about 2.1 times the fuel. It only flips at very high mileage.
Does this include buying the car?
No. This is what it costs to keep a car on the road for a year. If you are borrowing to buy it, put the monthly finance payment in the last box and it gets added. For the whole first year including learning to drive, see the first car page.
What mileage should I put in?
Your MOT certificate records your mileage every year, so two certificates give you your real annual figure. If you have never had a car, 4,000 to 6,000 miles is a normal first year unless you are commuting.
Does it work for an electric car?
Not properly. Petrol is priced per litre and electricity per kilowatt hour, so the fuel box would need to be a different box. Everything else on the page, the insurance, the tax, the servicing and the per mile idea, applies just the same.
Does this send my numbers anywhere?
No. Every sum happens inside the page on your own device. There is no account, no sign up and no server. Close the tab and it is all gone.
Read next
- DebtYour first car: the £7,145 nobody mentions
- DebtInsurance: why it costs what it costs at 17
- ToolsAll three calculators in one place
Last checked 27 August 2026.