A car with fewer miles on the clock is worth more, which is exactly why some cars have had their mileage wound back. This is known as clocking. It can add thousands to the price and hide wear that's about to cost you money. Here's how to check a car's mileage before you buy.

Why clocking still happens

Most modern cars have digital odometers, but that doesn't make them safe from tampering. The reading can be changed with equipment that plugs into the car. Changing a reading isn't the hard part. The giveaway is usually that the rest of the car's history and condition don't match the number on the dash.

It's against the law to sell a car with a wound-back mileage without telling the buyer, but that only helps you after the event. It's far better to spot it before you pay.

1. Check the MOT history first

Every MOT test records the mileage. If a car is more than three years old, you can see its whole history in seconds with a free MOT history check. Look for:

  • A reading lower than an earlier one. Mileage should only ever go up. A drop is the clearest warning sign there is.
  • A gap in the history. A missing year can be innocent (the car was off the road), but ask why.
  • Big swings in yearly mileage. 12,000 miles a year for five years, then 1,500 a year since, deserves an explanation.

Our MOT check flags mileage drops automatically, along with failures and advisories worth asking about.

2. Compare the paperwork

Service book stamps, invoices and old MOT certificates all carry a mileage and a date. Lay them out in order. They should rise steadily and agree with the MOT history. Be wary of:

  • a service book that looks brand new on a car that's several years old;
  • stamps from garages you can't find, or all in the same pen;
  • invoices with the mileage missing or changed;
  • no paperwork at all on a car advertised as low mileage.

If a dealer serviced the car, they can often confirm the mileage at each visit if you call them with the registration.

3. Look at the wear

Wear tells you how a car has really been used. It's hard to fake and expensive to hide. On a car showing low mileage, these should look fresh:

  • Steering wheel: shiny, worn or rubbed through at the 10 and 2 positions.
  • Gear knob and handbrake: faded print, shiny leather or wear on the button.
  • Pedals: worn rubbers, or rubbers that are brand new on an older car.
  • Driver's seat: a flattened or cracked outer bolster where you slide in.
  • Keys: buttons with the symbols worn off.

A brand new steering wheel, gear knob or pedal rubbers on an otherwise tired car can also mean someone has tried to hide wear.

4. Check what the car tells you

Some cars store mileage in more than one place, such as the engine or gearbox control units, or service reminders. A diagnostic scan can sometimes show readings that don't match the dashboard. That's one reason an inspection with an OBD2 scan is worth having on a car you're unsure about.

What to do if the mileage doesn't add up

  • Ask the seller to explain, in writing. Genuine reasons exist, such as a replaced instrument cluster with the correct mileage noted on an invoice.
  • Don't let the seller talk you into paying a deposit to "hold" the car while you check.
  • If you can't get a clear answer, walk away. There will be other cars.
  • If you've already bought a car and later find it was clocked, contact Citizens Advice for help with your rights.

Frequently asked questions

Can you tell if a digital odometer has been changed?

Not by looking at the display. You find out by comparing the reading with the MOT history, service records and the car's wear, and sometimes with readings stored elsewhere in the car.

Does a car history check show clocking?

Many paid history checks compare recorded mileages and flag discrepancies. The free MOT history shows the mileage at every MOT, which catches most cases on cars over three years old.

Is a low-mileage car always suspicious?

No. Plenty of cars genuinely do few miles. What matters is that the history, paperwork and condition all tell the same story.

Not sure about a car? Book an independent inspection and we'll check the car, its records and the wear against the mileage before you buy. You can also read our top 10 red flags when buying a used car.