How 73 Auto estimates the cost of owning a car
73 Auto builds a Total Cost of Ownership (TCO) estimate for a specific, identified vehicle by combining official UK vehicle data with a set of category-by-category cost models — depreciation, fuel or energy, insurance, servicing, repairs, tyres, tax and finance — then adds them together into one annual figure.
Last reviewed: 2026-07-20
Estimates, not guarantees
Every figure on 73 Auto is a modelled estimate. It is not a guaranteed future cost. It is not a quotation and it is not financial advice — it is informational only. Actual costs vary by the vehicle’s exact registration and condition, your location, how you drive, your specific insurance and finance circumstances, and future market changes (fuel prices, tax rules, insurance premiums). Use 73 Auto to compare and plan — not as a substitute for a real quote from an insurer, finance provider or garage.
Depreciation
Depreciation is modelled from the vehicle’s age, body/vehicle class, brand tier, fuel type and your chosen annual mileage. It estimates how much of the car’s value is likely to be lost over your ownership period, based on typical depreciation curves for similar vehicles — not a live resale valuation or a guaranteed trade-in price.
Fuel or energy
Fuel and energy costs are estimated from the vehicle’s official fuel type and engine data, a representative miles-per-gallon (or efficiency) figure for that type of vehicle, your driving style, and a default per-litre or per-kWh price — your own fuel or electricity price, if you provide one, is used instead of the default. Actual fuel/energy spend depends on real-world driving conditions, local prices and how the car is used.
Insurance
Insurance is estimated by 73 Auto’s own model, not fetched from a live insurer feed or a real quote. The estimate starts from a market baseline premium and adjusts it using known and inferred risk factors (vehicle risk, usage, location band, policy assumptions). Adding your own details on /profile — postcode, driving history, no-claims bonus and similar — narrows the estimate range and raises its confidence label. It is never a substitute for an actual insurance quote.
Servicing
Servicing costs (including MOT) are modelled from the vehicle’s age, class and annual mileage, using typical UK servicing intervals and costs for that type of vehicle. They do not reflect a specific garage’s price list or a booked appointment.
Repairs and maintenance
Repairs and maintenance (wear-and-tear items and an allowance for unscheduled repairs) are estimated from the vehicle’s age, mileage, class, brand tier and fuel type, using typical UK wear-and-tear rates and age-based repair risk for that type of vehicle. This is a statistical allowance, not a prediction of what will actually fail on your car.
Tyres
Tyre cost is estimated from a typical tyre lifetime in miles/kilometres for the vehicle, your annual mileage and driving style, and a representative price per tyre — not a quote from a specific tyre retailer.
Vehicle tax (VED)
Vehicle Excise Duty is calculated from official UK VED rules — using the vehicle’s CO2 emissions and first-registration date returned by DVLA — applied against the current published VED rate bands. This is the one category closest to a fixed, official figure rather than a statistical estimate, though VED bands and rates can change at future Budgets.
Finance
If you tell us how you’re paying for the car — cash, HP, PCP, lease or loan — the finance cost line reflects that payment type, and any quote, term, deposit or APR you give us is used directly. Where you leave one of these unspecified, 73 Auto’s finance line applies a standard default (such as a typical loan term or a market-average interest rate for that payment type) so the report still returns a usable monthly figure. The report’s confidence label reflects how much of the finance figure rests on your own inputs versus these defaults. As with every other category, this is a modelled estimate, not a quote from a lender — the real number on your actual finance agreement can differ.
Annual mileage and ownership period
Several categories — depreciation, fuel/energy, servicing, repairs and tyres — scale with how much and how long you drive the car. If you don’t provide your own annual mileage or ownership period, 73 Auto falls back to standard UK driving assumptions so the report still produces a usable estimate. Entering your real annual mileage and how long you plan to keep the car makes every mileage-dependent category more accurate to your situation.
How vehicle-specific data and your inputs change the result
When you enter a UK registration, 73 Auto looks up the vehicle’s official make, model, fuel type, engine, CO2 figure and MOT history (see Data Sources for exactly which sources are used and how). Every category then blends that vehicle-specific data with the cost models above, and — where you’ve provided them — your own inputs (postcode, insurance profile, finance details, driving style). Where a category’s model produces one, the report shows a confidence label so you can see at a glance which figures are backed by more of your own data and which are still resting on general assumptions — not every category currently returns a confidence label, which we treat as a gap to close rather than a claim that those figures are more certain.
See these categories applied to your exact car
Enter a UK registration to get the full category-by-category breakdown for that specific vehicle.
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