Car Running Cost Calculator
Fuel is the cost you notice, because you pay for it every week. The rest — insurance, road tax, MOT, servicing, tyres, and depreciation quietly happening in the background — is where most of the money actually goes. Put your own numbers in and you'll see your true cost per year, per month and per mile.
The figures below are sensible starting points, not quotes. Overwrite anything that doesn't match your car — the more honest the inputs, the more useful the answer. Everything is calculated in your browser and nothing is uploaded.
Yearly bills & costs (£)
Set depreciation to 0 if you plan to keep the car until it's worth nothing — just remember the money is real, it's simply already spent.
True cost per year
Per month
Per week
Per mile
Where the money goes
What's that trip costing?
Glasgow to Edinburgh and back is about 90 miles. To Aberdeen and back, roughly 290.
All-in
Energy for that trip: . The all-in figure bundles in the insurance, tax and servicing you're paying whether you drive or not.
Why the yearly figure hides the real number
Insurance and road tax arrive once a year as a lump sum, which makes them feel like an annual event rather than a weekly cost. Fuel arrives in dribs of £60 and feels continuous. The result is that most drivers can quote their car's MPG but have no idea what a mile of their own driving costs — which is the only figure that lets you compare a car, a commute, or a job that pays mileage.
Divide your total by your annual mileage and you get a cost per mile you can use for anything. If your employer or HMRC pays 45p a mile, a car costing 35p is quietly making you money and one costing 60p is quietly costing you £1,500 a year on 6,000 business miles. If your car costs 50p a mile to run, that "cheap" 40-mile round trip to a garage on the other side of Glasgow because it was £20 cheaper for the MOT has just cost you £20 in motoring alone.
Two things reliably surprise people. Depreciation is usually the largest single line, and it happens whether the car is driven or not. And servicing is far cheaper than the failures it prevents — the MOT advisory you ignore in March is the £400 repair in October.
Running cost questions
How do I work out the cost per mile of running my car?
Add up every annual cost — fuel or charging, insurance, road tax, MOT, servicing, tyres, repairs, parking and depreciation — then divide the total by your annual mileage. A car costing £4,000 a year over 8,000 miles works out at 50p per mile, and that figure is the only number that lets you compare two cars fairly.
Should depreciation be included in running costs?
For most owners it's the single biggest cost and the one people forget, because it never appears on a receipt. A rough way to estimate it is the difference between what you paid and what the car is worth now, divided by how many years you've owned it. If you own an older car outright and plan to run it into the ground, leaving depreciation at zero is a perfectly reasonable choice — just remember the money is still being lost, it's simply already spent.
Is HMRC's 45p per mile the same as my real running cost?
No. 45p a mile is the approved mileage allowance for the first 10,000 business miles in a tax year (25p after that), and it exists to simplify tax returns rather than to reflect your actual costs. A large petrol car in city traffic can genuinely cost more per mile than 45p, while a well-run small hatchback on cheap insurance can cost noticeably less.
What MPG figure should I use in the calculator?
Use what your car actually does rather than the official combined figure, which is usually optimistic. The quickest honest way to get it is brim-to-brim: fill the tank, note the mileage, drive normally, then fill to the brim again and divide the miles covered by the gallons used. Short town journeys around Glasgow can knock 20-30% off the manufacturer's number in winter.
Are electric cars cheaper to run?
The energy cost per mile is usually far lower than petrol or diesel, and there's no engine oil, cambelt or exhaust to pay for. What's left is the same list as any other car — insurance, tyres, brakes, MOT and depreciation — and electric vehicles now pay road tax too, so put a real figure in the tax box instead of zero. Switch the fuel type to Electric in the calculator and it will work off miles per kWh and pence per kWh instead of MPG.