Car Running Cost Calculator & Cost-Per-Mile Tool

Add up fuel, insurance, road tax, MOT and servicing into a yearly, monthly and pence-per-mile cost, using your own figures, in your browser.

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The Motwatch car running cost calculator provides UK drivers and family household budget planners with one place to add up what a car costs to run. Operating a motor vehicle entails far more than the initial purchase price or monthly finance repayments. Fuel consumption, annual motor insurance premiums, Vehicle Excise Duty (road tax), mandatory MOT testing, and periodic mechanical servicing create substantial ongoing financial demands.

The calculator takes your annual mileage, real-world mpg, pump price, insurance, tax, MOT and servicing figures and turns them into a yearly total, a monthly figure and a cost per mile. Everything runs in your browser; nothing you type is sent anywhere.

UK figures on this page checked 3 November 2026: standard vehicle tax £200 a year (rates from 1 April 2026), maximum car MOT fee £54.85, HMRC approved mileage rate 55p a mile for the first 10,000 business miles in 2026–27.

Car running cost calculator example

How to use the car running cost calculator

  1. Enter estimated annual mileage: Type your total projected driving distance across commute, leisure, and holiday travel.
  2. Input real-world fuel economy (MPG): Input your vehicle’s actual average miles per gallon from your trip computer rather than lab estimates.
  3. Enter current local fuel price: Type the prevailing forecourt fuel price in pence per litre for standard unleaded or diesel.
  4. Input annual car insurance premium: Enter your yearly premium (or 12 times the monthly payment).
  5. Add road tax and MOT: Combine your annual vehicle tax (£200 standard rate for most cars registered since April 2017, more if the expensive car supplement applies) and the MOT fee (up to £54.85 for a car; none in the first three years).
  6. Estimate annual routine servicing and tyres: Budget for oil changes, brake pads, wiper replacements, and periodic tyre renewals.
  7. Inspect total annual operating cost: Review your combined cumulative annual motoring expenditure excluding capital depreciation.
  8. Examine monthly financial equivalent: Budget for regular monthly direct debits and savings allocations needed to cover motoring costs.
  9. Review true pence-per-mile expenditure: Compare your cost per mile with the HMRC approved mileage rate (55p a mile for the first 10,000 business miles in 2026–27).
  10. Identify areas for cost optimization: Compare insurance comparison quotes, practice smooth eco-driving to boost MPG, and shop for competitive service deals.

Technical specifications and architecture

Fixed and Variable Running Costs

It helps to split running costs into two kinds. Variable costs fluctuate in direct proportion to mileage driven: fuel, tyre wear, brake pad consumption, and mileage-based servicing intervals. Fixed costs stay the same regardless of whether the vehicle covers 1,000 miles or 20,000 miles per year: annual comprehensive insurance, Vehicle Excise Duty, the annual MOT inspection fee, and calendar-based service checks. Adding both gives the yearly total the calculator shows.

Fuel Expenditure Calculations in Imperial Gallons

In the United Kingdom, fuel economics involves an unusual hybrid measurement system: fuel is purchased and priced in litres at retail forecourts, while fuel economy is usually quoted in miles per gallon (MPG). One UK Imperial gallon equals exactly 4.54609 litres (unlike the smaller US gallon of 3.785 litres). To determine annual fuel expenditure, our calculator converts annual mileage into required gallons (Mileage / MPG), multiplies by 4.54609 to obtain total litres, and multiplies by the pump price you enter.

The True Cost Per Mile Metric

Cost per mile makes cars and journeys easy to compare. For example, 8,500 miles a year with £2,500 of running costs works out at £2,500 ÷ 8,500 = 29.4p a mile. Because insurance, tax and MOT stay the same however little you drive, a low-mileage driver pays far more per mile: £1,500 of fixed costs over 3,000 miles is 50p a mile before any fuel. Understanding this metric helps commuters evaluate public transit season tickets versus private vehicle commuting.

HMRC Approved Mileage Allowance Payments (AMAP)

For employees who use their own car for business travel, HMRC’s approved mileage allowance payment (AMAP) rate for cars and vans is 55p a mile for the first 10,000 business miles in the 2026–27 tax year (up from 45p) and 25p a mile after that. It is meant to cover fuel and a share of wear, insurance and servicing. If your employer pays less than the approved rate, you can claim Mileage Allowance Relief on the difference from HMRC.

Frequently asked questions

What is the average annual cost of running a car in the UK?

It varies too much by driver, car and postcode for one honest average: insurance alone can range from a few hundred to several thousand pounds. Put your own quotes and mileage into the calculator above; the default example (8,500 miles, 44 mpg) comes to about £2,540 a year before depreciation.

How do I calculate my car’s cost per mile?

Divide your total annual motoring expenses (fuel + insurance + road tax + MOT + servicing + repairs) by your total annual mileage driven, then multiply by 100 to get pence per mile.

Does the HMRC mileage rate cover all car expenses?

It is meant to. The approved rate (55p a mile for the first 10,000 business miles in 2026–27, 25p after) is a flat amount intended to cover fuel plus a share of insurance, tyres, depreciation and servicing for business journeys.

What is the biggest running cost of owning a car?

Excluding depreciation, fuel is typically the largest running cost for high-mileage drivers, while car insurance and depreciation represent the largest costs for younger or low-mileage drivers.

How can I lower my annual car running costs?

Lower your running costs by shopping around for insurance a few weeks before renewal, keeping tyres correctly inflated to boost MPG, and learning basic DIY maintenance checks.

How does inflation affect annual car running costs?

Fuel, parts, labour and insurance prices all move with inflation, so re-run the calculator with new figures at each insurance renewal or when pump prices change.

See all Car Running Cost and Finance Tools.