Clocking is the easiest serious fraud to commit on a used car and one of the easiest to catch, because the state has been writing the odometer down once a year for two decades. Every MOT test records the mileage, the DVSA publishes the series free against the registration, and reading it takes about a minute. The paid products extend that series with readings the MOT does not capture. The free half does most of the work.
How to check mileage on car MOT records for free
Pull the MOT history and write the readings out by date. You are looking for three things: a reading lower than the one before it, a year with implausibly low distance followed by a jump, and a current odometer that does not fit the line the tests were drawing. Any of those is a conversation. A single anomalous figure in an otherwise straight line is usually a keying error at the test station, and the test certificate will often show the correction at the next visit.
Where the free series stops
It starts at the first MOT, which is the third anniversary of registration, so a two year old car has no series at all. It has one reading a year, so a car clocked and then driven normally can produce a plausible looking line. And it covers only tests, so imports, long periods off the road and vehicles exempt from testing leave gaps. Paid products add readings from service records, finance settlements, trade sales and valuation events, which fills some of those holes.
Digital odometers made it easier, not harder
Winding back a mechanical odometer took tools and left evidence. Altering a digital one takes a laptop, a cable and a few minutes, and there is often nothing to see on the cluster afterwards. The counter is that the number now also exists in several other places in the car, in the service record and in the national test database, and a professional inspection can read some of those. A car whose modules disagree with its dashboard is a car to walk away from.
When the numbers do not add up
Selling a vehicle with a misrepresented odometer reading is an unfair commercial practice, and a trader who does it is committing an offence rather than driving a hard bargain. Keep the advert, the written mileage claim and the report. Report a trader to Trading Standards through the consumer service, and tell the finance company too if the car was bought on an agreement, because they own the car and have their own interest in the fraud.
Questions people ask about car mileage check
How do I check a car's mileage history for free?
Run the DVSA MOT history against the registration. Every test since 2005 lists the recorded mileage, which is the same clocking check most paid reports resell with extra readings.
Why does the mileage drop at one test and then carry on?
Usually a typing error at the test station. Look at whether the following tests resume the original line; a genuine clock normally shows a drop that the later readings then build on from the lower figure.
Does a vehicle mileage check work on a car under three years old?
No. There is no MOT until the third anniversary of registration, so there is no free series. On a young car the service record and the finance history are the only mileage evidence.
Is clocking illegal?
Selling a vehicle while misrepresenting its mileage is an unfair commercial practice and is enforced against traders. Adjusting an odometer is not itself an offence, which is why the fraud is in the sale rather than the tool.