A car can look affordable on its monthly repayment and still leave you short when the insurance renews or the tyres need replacing. A useful budget combines regular spending with savings for annual bills and repairs. It also accounts for timing: the money needs to be available when each bill arrives, not simply balance out over a year.
Start with your monthly cash commitments
List regular payments first, then add savings for less frequent expenses. Insurance and finance commitments still need funding during a month when you barely drive. Buying outright or paying a deposit also calls for separate money at the outset.
Bad credit car finance repayments need to leave room for fuel, insurance, maintenance and a repair reserve.
Depreciation, the car’s loss in value, belongs in comparisons of ownership costs and eventual resale values. As it is not a monthly bill, keep it separate from this cash budget.
Calculate fuel and other regular spending
Estimate annual mileage from commuting, shopping, family visits and longer trips. Existing mileage records give you a firmer starting point than your commute alone.
For petrol or diesel, use:
Annual miles ÷ UK mpg × 4.546 × price per litre (£) = annual fuel cost
The conversion uses litres per imperial gallon. For the worked budget below, assume 7,200 miles a year, 45 mpg and £1.50 per litre. That produces an estimated fuel bill of £1,091 annually, or £91 monthly.
Use realistic fuel consumption rather than relying on an advertised figure. For an electric car, use actual charging expenditure where available, or calculate consumption against the tariffs you expect to use.
Add parking, tolls and applicable local driving charges for your usual journeys. Station parking or a regular toll-road trip belongs in the everyday budget, rather than among occasional extras.
Allow for annual bills and unexpected repairs
Get an insurance quote for the specific car. Compare the total payable annually or in instalments, including any interest or fees.
Check the vehicle’s applicable tax rate, too. For bills paid annually, divide the amount by 12 to establish an ongoing savings allowance.
Separate planned maintenance from unexpected repairs. Allow for MOT testing where required, servicing, tyres and work already identified, using the maintenance schedule and quotations to estimate costs.
Then build a reserve for unexpected faults. Budgeting separately for a known tyre replacement keeps that reserve available for an unforeseen breakdown. Choose a contribution based on existing savings and potential bills you would struggle to pay. Include any chosen breakdown cover as a separate expense.
Build one monthly car budget
This example combines the fuel calculation above with illustrative bills and savings targets. These are budgeting assumptions, not UK averages or current price quotations. Replace them with your own figures.
| Payment or savings allocation | Monthly amount |
|—|—:|
| Fuel | £91 |
| Insurance | £60 |
| Vehicle tax | £20 |
| MOT, servicing and tyres | £35 |
| Unexpected-repair savings | £40 |
| Parking and road charges | £20 |
| Breakdown cover | £5 |
| Running-budget subtotal | £271 |
| Illustrative finance repayment | £180 |
| Combined monthly requirement | £451 |
The £271 subtotal includes money reserved for future bills as well as immediate spending. The £180 repayment is a separate purchase commitment.
When a repair bill is paid from the reserve, record it against that savings pot. The monthly contributions have already accounted for it in this budget; counting the withdrawal again would duplicate the cost. Continue contributions to replenish the reserve afterwards.
Check when the money will be needed
For a bill due soon, divide the amount still needed by the number of months until payment.
Suppose the £35 maintenance allowance represents £420 across a year. A £420 bill is due in three months, and you have £120 saved. The remaining £300 requires £100 a month until payment.
That temporarily increases the example’s monthly requirement by £65, from £451 to £516. Once the bill is paid, recalculate contributions around the next expected expenses.
Write down forthcoming bills, their dates and the savings available. Check whether higher fuel spending or another unexpected expense would force you to use money earmarked elsewhere.
Compare the requirement with income left after household essentials and existing commitments. If there is a shortfall, reconsider the vehicle or travel plan before committing. The test is whether you can fund the expensive months as well as the quiet ones.
Matthew Wilde
Matthew Wilde is an automotive journalist with experience contributing to leading publications. He focuses on delivering clear, well-researched analysis of automotive industry news and vehicles. Growing up surrounded by a variety of cars, Matthew developed a strong foundation in automotive technology and design. His work emphasizes accuracy and depth, aimed at informing both enthusiasts and industry professionals with straightforward, precise reporting.
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