How to Check the Real Mileage of a Used Car Before You Buy

Buying a used car can be an excellent way to save money, but it also comes with a few risks - including finding out the vehicle has covered more miles than the advert suggests. So, if you’re considering a second-hand car but you’re unsure whether the information you’ve been given is accurate, the guidance below can help you check.

Knowing the genuine mileage is crucial when judging how much wear a car is likely to have. According to a 2023 Stellantis study, a petrol vehicle covers around 15,000 kilometres per year on average, while a diesel vehicle can reach 25,000 kilometres annually.

The good news is that there are practical steps you can take to reduce the risk and verify the real mileage before you commit to the purchase.

Check the vehicle history

Your first - and most important - move is to look up the car’s history. In Portugal, you can do this through the IMT for national vehicles, or via VinInfo for imported cars. These checks can show records of periodic inspections and declared mileage, among other useful details. Be aware that there may be fees for accessing this information.

A history that progresses steadily from one inspection to the next is a strong sign the odometer reading (total mileage counter) is reliable. If you spot an unexpected drop or a sudden inconsistency in the figures, it may indicate tampering.

To strengthen your checks, remember that many garages record the mileage each time the car is serviced. Set those numbers alongside what the dashboard shows: repeated mismatches or unusually large jumps can suggest the odometer has been altered.

Look for visible wear and tear

Even without official paperwork, you can often spot clues that the mileage has been manipulated. Examine physical wear on items such as the pedals, steering wheel, seats and floor mats, and also consider the overall condition of the engine and suspension. If the car looks far more worn than the displayed mileage would imply, treat it with caution.

Use diagnostic tools to confirm mileage

On newer models, mileage is stored digitally in electronic control units. An authorised workshop or a trusted mechanic can access this information using diagnostic readers and confirm the real kilometres.

On older vehicles, where this digital record may not exist, check whether the odometer digits are misaligned and look for marks suggesting someone has tried to open the instrument cluster.

Arrange a full inspection before you buy

Taking the car to a mechanic prior to purchase is essential. As well as checking mileage, this inspection can uncover mechanical issues that may result from heavy use. A professional assessment provides reassurance and can also give you leverage when negotiating the price.

Be wary of prices that seem too low

A selling price that is well below market value can be a red flag for hidden issues, including falsified mileage. Compare it with listings for similar models and be sceptical of “can’t-miss” bargains.

Finding the real mileage of a used car takes a bit of investigation, but it can prevent serious headaches later on. Checking histories, reviewing records, assessing wear, using diagnostic tools and getting a mechanic’s opinion are key steps towards a safer, better-informed purchase.