True cost of a car calculator, in hindsight

What if I'd bought a cheaper car and invested the difference?

Pick the year you bought. This replays real car prices, loan rates and investment returns for the car you bought and a cheaper one, with the difference invested, to the latest month.

Where
Paid with
Year you bought
Replace each car every
Your numbers

£e.g.
£e.g.
The cheaper car was

Car loan

%avg
10% down on either car

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What each choice leaves you with: the money invested, plus what the car is worth, minus any loan. The lines jump when the cars are replaced: the same money goes out on both sides, and the cheaper side invests what its car didn't cost. Touch the chart to scrub.

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How it played out

Where the money went

Both start with the same money and spend the same each month. Whatever the cheaper car doesn't cost, it invests.

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Assumptions you can change

How this true cost of a car calculator works

This true cost of a car calculator replays what a car really cost you: not only its price, but what the money would have grown to if you had bought a cheaper car and invested the difference. Pick UK or US, the January you bought (from 2000 on), cash or a loan, and how often you replace your car. It follows both choices to the latest month.

Both start with the same money and spend the same each month. The cheaper car costs less up front, or less each month on a loan, and that difference is invested in the S&P 500 with dividends reinvested (or earns savings rates, or nothing, as you choose). Each car loses value on a standard curve, moved with used car prices as they really changed, and when it's time to replace it, it's traded in for the same kind of car at that year's prices. What each choice leaves you with is the money invested, plus the car's value, minus any loan still owed.

The prices are examples in today's money (£40,000 against £20,000 in the UK, $50,000 against $25,000 in the US), taken back to the year you pick with new or used car price indices; type your own over them. A loan takes 10% down, at that month's average rate: the Bank of England personal loan rate, or the Federal Reserve new car loan rate, with 2 points more for a used car. Repairs start once a car is 3 years old, the same on either car.

Worked example

These use the calculator's starting figures for one UK and one US case, and are refreshed when the data updates.

Had you bought a £14,000 car instead of a £28,100 one in January 2015 and invested the difference, replacing it every 8 years, by August 2026 you'd have £90,485 more: £108,511 with the cheaper car, against £18,026.

Had you bought a $20,400 car instead of a $40,800 one in January 2015 and invested the difference, replacing it every 8 years, by August 2026 you'd have $118,529 more: $143,345 with the cheaper car, against $24,816.

Where the numbers come from

  • UK: loan and savings rates and exchange rates from the Bank of England. New and used car prices from ONS consumer price indices. Stock market: S&P 500 with dividends, in pounds, from Robert J. Shiller's data. Contains ONS data © Crown copyright, licensed under the Open Government Licence v3.0.
  • US: car loan rates from Federal Reserve G.19, 48-month new car loans at banks. New and used car prices from BLS consumer price indices. Treasury bills from the Federal Reserve, via FRED. Stock market: S&P 500 with dividends, from Robert J. Shiller's data.

Questions

What is the true cost of a car?

Its price, loan interest and repairs, less what you get for it when you sell, plus what that money would have earned if you had spent it on something cheaper and invested the rest. The big figure above is that last part: how much more (or less) the cheaper car would have left you with by the latest month, counting both cars' value today.

Should I sell my car and buy a cheaper one?

This replays the past rather than forecasting, but it shows what the swap has been worth. Pick the year you'd have switched, type the price of your car and of the cheaper one, and choose "3 years old" if the cheaper one would be used. Try a few start years: the gap depends on what stocks did while the difference was invested.

How much does an expensive car cost over 10 years?

Choose "Never" under "Replace each car every" and a start year ten years back. The table shows what each car cost in price, interest and repairs, what it's worth now, and what the money not spent on the dearer car grew to.

Is a used car cheaper than a new one in the long run?

Pick "3 years old" for the cheaper car and type the same model's used price. The used car starts older, so it needs repairs sooner and, on a loan, pays a higher rate, but it avoids the steep first years of losing value. Used car prices as they really moved, including the 2021 to 2022 jump, set what each car is worth along the way.

What does the calculator leave out?

Insurance, fuel, road tax and sales tax are left out on both sides; a dearer car usually costs more to insure, so the real gap is a little wider. Tax on investment growth is left out too. Each car's value follows a standard depreciation curve moved with used car price indices, not the price of any particular model.