A car is priced by its payment and paid for by everything else. Insurance, fuel or charging, maintenance, tyres and road tax arrive every month, and depreciation reduces what the car is worth whether or not it appears on a statement.
Insurance is the line that varies most between models, and it is a fixed monthly cost for as long as you own the car. Fuel or charging depends on distance and driving style rather than on the price of the car: an efficient car driven a long way can cost more in fuel than a thirsty one driven rarely. Maintenance is irregular, which is why it is best averaged over a year rather than estimated month by month. The Car Affordability Calculator puts all of these together and compares the total with a 15% ceiling on take-home pay.
Depreciation is deliberately excluded from that figure because it is not a cash payment, but it is the largest single cost of a new car and the reason buying two or three years old is usually cheaper over the whole period of ownership. A car that loses a fifth of its value in the first year costs that money whether you sell it or not.
Distance is the input that changes the answer most. Below a few thousand miles a year, the honest comparison is often the cost of ownership against public transport plus occasional rental, and the answer is not always the car. The Fuel Cost Calculator prices the driving, and the EV Charging Cost Calculator shows what the same distance costs on electricity, which depends heavily on whether you can charge at home.
Whatever the total, the car competes with savings. A car that fits the month it starts but not the month a boiler breaks is how a transport decision becomes a debt decision, and the emergency fund is what stands between the two.