Cost per Kilometre Calculator

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.

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.

Worked example

Suppose you own a vehicle with the following annual costs:

• Annual fuel: 1,500
• Annual maintenance: 600
• Annual insurance and tax: 1,200
• Annual depreciation: 1,200
• Annual distance: 20,000 km

Total annual cost = 1,500 + 600 + 1,200 + 1,200 = 4,500

Cost per kilometre = 4,500 ÷ 20,000 = 0.225 per km

In this scenario, fuel alone accounts for 1,500 ÷ 4,500 = 33% of total cost, with depreciation, insurance, and maintenance making up the remainder.

When this metric matters

This calculation becomes relevant in several contexts:

• Comparing the cost of car ownership against public transport or ride-sharing services
• Deciding whether a long commute remains economical
• Evaluating the impact of changing annual mileage on total vehicle running cost
• Understanding how vehicle choice affects cost structure (smaller vehicles may have lower depreciation and fuel costs)
• Budgeting transport expenses across a business or household

What the result shows and does not show

The calculator shows the average cost incurred per kilometre driven, based on the annual figures entered. It illustrates how depreciation, maintenance, and fuel combine to determine true driving cost.

The result does not account for:

• Seasonal variation in maintenance or fuel prices
• One-off repairs or unexpected expenses
• Changes in annual mileage in future years
• Residual value or resale conditions
• Regional differences in fuel or insurance costs
• Personal usage patterns (city versus highway driving, which affects fuel economy)

Educational note

This calculator provides an illustration of how running costs distribute across a vehicle's annual use. The output is an estimate based on the inputs provided and is intended for educational comparison, not as a guarantee of actual cost or a substitute for detailed financial planning.