Some cars are bought with the heart. Nobody runs a spreadsheet on their dream car, and nobody should. Most car purchases aren't that, though. They're transport: the commute, the school run, the dog in the boot. For those, there's a better way to decide than gut feel and showroom pressure, and it's the boring one. Data and maths. That's the gap this tool tries to fill.
The maths starts from a fact the industry rarely leads with: a car loses value every single day you own it, and that loss is the biggest cost of driving. Bigger than fuel. Bigger than interest. Every way of paying for a car is really just a different answer to the same question: who pays for that lost value, and what do they charge you for the favour?
You buy it, you own it, you sell it. You carry all the depreciation yourself, but nothing else. No interest, no fees. There's one subtle catch: the money sitting in the car could have been earning a return somewhere else, and that invisible cost is real.
A loan wearing a car badge. Deposit, then fixed monthly payments until the car is yours. You still pay all the depreciation, plus interest on top. Simple and honest. Rarely the cheapest.
Lower monthlies, because a big slice of the price is parked in an optional final payment (the balloon) set at a guaranteed future value. You're mostly financing the depreciation rather than the car. Flexible at the end: pay the balloon and keep it, or hand it back and walk away. Whether it's a good deal comes down to the APR and where they set that balloon.
You never own the car. You rent it for a fixed term and give it back. What you pay is the depreciation the leasing company expects, plus their funding and margin. When a manufacturer wants to shift a model they subsidise that expectation, which is why a lease occasionally beats every form of buying. The tool spots when that's happening.
Same car, same years behind the wheel, and these four routes can still differ by thousands of pounds. Which one wins depends on the model's depreciation curve, the finance rates on the table, and what your money could earn elsewhere. Intuition can't weigh all of that at once. Arithmetic can, and arithmetic is cheap now.
The depreciation curves behind this tool come from a snapshot of live UK asking prices that we pulled and crunched ourselves, by hand. Nobody sold us an industry data feed. We've checked our curves against the residual forecasts manufacturers publish inside their own PCP offers, and they line up sensibly, but they are still estimates. Take every figure with a grain of salt.
What the numbers are for is guidance. Buying a car is one of the biggest purchases of your life, and seeing its true shape clearly, even approximately, beats deciding on a monthly payment alone. But nothing here is a quote, a valuation, or financial advice.
Also not covered yet: reliability and repair costs. A cheap car to buy can be an expensive car to keep, and nothing here reflects that. If people find this tool useful, that's the next thing we want to build. EVs are mostly missing too, because their used values are currently moving too fast for anyone to forecast honestly.