How we calculate running costs

Every figure on CarAI is an estimate built from the assumptions below — not a quote. Your real costs depend on your age, location, driving record, the exact car and the deal you get. If a number looks wrong to you, tell us with the 👎 button on a quiz result.

Prices

• Buying means a 2–4-year-old car (registered 2022–2024). Its price is the typical asking price in real listings, checked in October 2026: Autotrader for the UK and auto24.ee for Estonia. Used cars cost noticeably more in Estonia than in the UK, so each country has its own price.
• Leasing means a new car, priced at the top of the model's new range (current model, higher trims). New prices are held in euros and converted for the UK at €1 = £0.86.

Buying on finance

• 20% deposit; the other 80% on a 3-year loan at 5% APR.
• Resale value after 3 years: about 55% of what you paid. Buying is shown net of this, because you keep the car.
• Maintenance: about 10% of the purchase price spread over 3 years.

Leasing

• UK: real personal lease deals, checked in October 2026 on leasing.com — 36 months, 10,000 miles a year. We take the 10 cheapest deals for each model and use the middle one. The upfront payment (usually 6–12 months' worth) and broker fees are spread across the 36 months, so the figure is what the lease really costs per month. Road tax is included; insurance and fuel are not.
• Estonia: private leasing is mostly long-term full-service rental, and few prices are published. We estimate the payment as about 45% of the new price over 36 months and add our insurance estimate; against the quotes we could check, this lands within about 15% either way. Full-service rental usually includes insurance, servicing and tyres, and prices are often quoted without VAT — check what a quote includes.

Fuel and electricity

• Default distance: 1,000 km a month (about 7,456 miles a year) on mixed roads. In the quiz you choose your own mileage and road type; city driving adds 25%, motorway driving takes off 15%.
• Consumption: the model's typical real-world figure.
• UK: petrol £1.66/L, diesel £1.91/L (October 2026 averages), electricity 26.3p/kWh (Ofgem price cap, October–December 2026).
• Estonia: petrol €1.95/L, diesel €2.10/L (early October 2026), electricity €0.26/kWh including network fees and taxes.
• Hybrids use the petrol price. Electric cars assume charging at home; public rapid charging costs two to three times more.

Insurance

• 3.5% of the car's value a year, but never less than €500 (£430) a year. This is a rough average; young drivers and city postcodes pay much more.

Road tax

• UK: a 2–4-year-old car pays the standard rate of vehicle tax, £200 a year (April 2026 rate), whatever its fuel type or CO₂ — electric cars included since April 2025. Cars with a list price over £40,000 pay £640 a year extra in years 2–6; that supplement is mentioned on the page but not included in the totals. Source: GOV.UK vehicle tax rates.
• Estonia: the motor vehicle tax depends on the car's mass, CO₂ and age, so we don't include it. Use the Transport Administration calculator for the exact figure. This page in Estonian →