CarCostMethodology
How we calculate ownership cost
This page explains where the numbers behind the Calculator and Compare Cars tool come from, and what to keep in mind when reading them. For a plain-language walkthrough of the underlying concepts, see the Car Cost Guides.
Live market data first
When you run a calculation, the tool searches the live web for current fuel prices, typical maintenance costs, insurance premiums and government charges for your specific make, model and city — rather than relying on numbers that go stale. Figures pulled from search results are validated against a plausible range for the selected currency before being used.
When live data isn't available
If live search fails outright (a network or API issue), a currency-specific fallback baseline is used instead. If search succeeds but simply returns nothing usable for a value — for example, no reliable insurance quote for an unusual vehicle — that figure is marked as unavailable rather than silently replaced with a guess.
What's included — and what isn't
The calculator covers recurring running costs (fuel or electricity, maintenance, insurance, annual road/token tax) plus your one-time registration fee and, if you're financing, your monthly loan installment. These combine into a monthly total, an annual total, and 3- and 5-year projections of those same recurring costs.
It does not currently estimate vehicle depreciation, resale value, the vehicle's purchase price itself, or occasional costs like tires, parking, tolls or detailing. "Ownership cost" on this site refers specifically to the running/recurring costs above, not the complete lifetime financial cost of owning the car.
Registration vs. annual charges
Government charges are split into a one-time registration fee and a recurring annual token/road tax, since combining them would overstate the ongoing cost of owning the car. See the government charges guide for the full breakdown.
Limits of the estimates
Every figure here is an estimate built from user-provided inputs and available market data. Actual costs vary by fuel price movements, driving conditions, the workshop or insurer you use, and local government policy. Sources are shown alongside each result so you can judge them yourself rather than take them on faith.
Want the full picture? Read the Car Cost Guides or try the Calculator.