How we compare cars
We compare cars only on what we can stand behind. That's each car's condition now, how it's likely to hold up, and its running and repair costs. Every number is a range, not a quote.
Each car gets a risk rating from its full MOT history. That covers what failed, what came back, advisories never sorted and any dangerous defects. The rating runs from Very Low to Very High, with the main things worth knowing about.
A car that's too new for an MOT shows an early read from how similar cars start out, marked as a forecast.
We start from how cars of the same make, model and age usually do at their MOT as they get older. Then we adjust it to the car you entered, using its own MOT record and its mileage. A cleaner record, or fewer miles, gives a kinder outlook than a rough, high-mileage car of the same model. We also name the parts (brakes, suspension and so on) that usually start needing work.
Two honest caveats. First, this is the usual pattern for cars like yours, adjusted for its record. It's not a tracked prediction of your exact car. Older cars still on the road tend to look a little better than the full picture. So we ease off the expected decline as cars age. Second, we may not have enough history for that exact model, or enough data to be confident. Then we use the usual pattern for cars of the same age and fuel, and say so. The comparison then leans on condition now rather than naming a forward “winner”.
The yearly running cost adds up four things, each shown as a range:
- • Fuel or electricity: from your yearly mileage and the car's economy, at current pump and tariff prices.
- • Road tax (VED): from the car's registration date, emissions and fuel, using the current UK rates. The £440 “expensive-car” supplement is only added when the model clearly had a list price over £40,000 when new (£50,000 for electric cars). We'd rather leave it off than add it to a car that doesn't owe it.
- • Servicing: typical minor and major service costs for the car's age and mileage.
- • Wear: tyres and brakes, scaled to how far you drive.
If we can't price a car's fuel type (for example hydrogen or LPG), we leave the running cost blank rather than guess. We don't include insurance: it depends too much on the individual driver. Loss of value is left out too, as on every MOT Wise page.
For the repair figure we take the faults that cars of this model and age often fail on or get advisories for. We weight each by how often it shows up, and multiply by a typical UK independent-garage repair cost. We add that up over the years you plan to keep the car, a year older each year.
We also name the parts most likely to be behind it (for example “typically brakes, suspension, tyres”). It's a planning figure for a typical car of that kind, not a prediction for your car. If we don't have enough fault data for a model, we say so rather than show a number.
We don't show purchase price, loss of value (depreciation) or resale value here, and we don't ask for service-history paperwork. That's a deliberate choice:
- • Price and loss of value: we can't estimate resale value accurately enough yet to stand behind it, so we'd rather leave it out than mislead. We'll bring it back once we have better data.
- • Service history: it isn't in the official MOT or DVLA data we hold. A typed-in answer we can't check wouldn't make the comparison more accurate. The MOT record already shows how a car has been looked after.
Accuracy on what we know beats a fuller-looking page built on guesses.