FinToolSuite

Cost per Kilometre Calculator

Updated April 17, 2026 · Utilities · Educational use only ·

True cost to drive each kilometre.

Calculate the real cost per kilometre of driving, including fuel, maintenance, insurance, and depreciation. Enter fuel cost and see the result instantly.

What this tool does

Enter annual running costs and annual distance. The tool calculates cost per kilometre driven.


Enter Values

Formula Used
Annual fuel spend
Annual service costs
Annual insurance + tax
Value lost per year
Annual km driven

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Calculations, display, or translation — let us know.

Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

Per-kilometre driving cost includes more than fuel. Maintenance, insurance, road tax, and depreciation often add up to twice the fuel cost. A car costing 2,000 in fuel plus 2,500 in everything else, driven 15,000 km a year, costs 30p per km — not 13p. This is the number to use when comparing driving to train, rideshare, or declining a long commute.

Quick example

With annual fuel cost of 2,000 and annual maintenance of 800 (plus annual insurance + tax of 900 and annual depreciation of 800), the result is 0.30. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Annual Fuel Cost, Annual Maintenance, Annual Insurance + Tax, Annual Depreciation, and Annual Distance. Frequency and unit price pull the total in different directions. The biggest surprise for most people is how small recurring amounts compound into large annual figures — that's where this calculation earns its keep.

What's happening under the hood

Total annual cost divided by annual distance. Includes fuel, maintenance, insurance, tax, and depreciation for a full running cost. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

Using the result to negotiate

The figure gives you a concrete number to quote when shopping alternatives. "I'm paying £X annually" cuts through marketing in a way "I want a better deal" doesn't. The specificity wins.

What this doesn't capture

Usage varies month-to-month; tariffs change; discounts come and go. The figure here is a clean baseline — your actual annual bill will fluctuate around it. Use the calculation to benchmark providers, not as a prediction of a specific bill.

Example Scenario

Cost per kilometre produces a per-km figure based on the inputs provided.

Inputs

Annual Fuel Cost:2,000 £
Annual Maintenance:800 £
Annual Insurance + Tax:900 £
Annual Depreciation:800 £
Annual Distance:15,000 km
Expected Result£0.30

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

Total annual cost divided by annual distance. Includes fuel, maintenance, insurance, tax, and depreciation for a full running cost.

Frequently Asked Questions

Do I need to include depreciation?
Yes if you want the true cost. Depreciation is real money — the car is worth less each year. Excluding it understates the cost by roughly a third for most cars.
How do I estimate depreciation?
(Purchase price - current value) / years owned. Or use a rule of thumb: 15-20% in year one, 10-12% per year after.
What about electric?
Same structure, different numbers. Fuel becomes electricity cost. Maintenance is usually lower. Depreciation patterns differ — research before assuming a rate.
Is this the right number for trips?
For occasional trips, most drivers use a marginal cost (fuel only). For lifestyle decisions — commute length, second car — the full per-km figure is the right one.

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