Odometer reading: how to read it, record it, and trust it

The odometer records the cumulative distance a vehicle has traveled since it was built. It is driven by the same signal that feeds the speedometer, which is why changing tire size without recalibration affects both.

It is the closest thing a car has to an age in usage terms, and it is why two vehicles of the same model year can be priced very differently. Calendar years age rubber, seals and paint; miles age the drivetrain, suspension and everything that moves.

1. 1Switch the ignition onOn most modern vehicles the cluster needs to be powered for the display to appear. You do not need to start the engine.
2. 2Find the largest number on the clusterOn digital displays the odometer is usually the most prominent figure, frequently labeled ODO or MILES.
3. 3Cycle the display if you cannot see itSome vehicles hide the odometer behind a menu. Use the stalk button or the steering wheel controls to cycle through the trip computer screens.
4. 4Confirm it is not the trip meterThe odometer shows whole units with no decimal, and cannot be reset. If a long press zeroes the number, that was a trip meter.

Manufacturers place the odometer differently across model lines, and on vehicles with fully configurable instrument displays it may not be visible in every layout.

• Try the stalk button on the end of the wiper or indicator stalk
• Try the steering wheel controls, which drive the trip computer on many vehicles
• Look in the vehicle information or service menu on the central screen
• On vehicles with configurable clusters, switch display themes — some hide it
• Check the vehicle's own app or software menus, where some makes surface it
• On a car that will not power up, the reading may only be recoverable at a workshop

Vehicles sold in the United States record miles. A vehicle originally sold in Canada, Mexico or overseas may record kilometers, and imported vehicles frequently do.

The unit matters enormously to value, because the same number means very different things. Roughly, a kilometer is about six-tenths of a mile — so a reading of 200,000 km is closer to 124,000 miles. Check the label on the cluster before you price anything, and be alert to a seller quoting a kilometer figure as though it were miles.

• Read the odometer, not a trip meter
• Record whole units exactly as displayed — do not round
• Note whether the reading is in miles or kilometers
• Photograph the cluster with the reading visible
• Record the date alongside the reading
• Keep the photograph with your sale paperwork

Federal law requires the seller of a vehicle to provide the buyer with a written disclosure of the odometer reading at the time of title transfer, and to state whether that reading reflects the actual mileage.

The disclosure typically appears on the title document itself, and it asks the seller to certify one of three things: that the reading is the actual mileage, that it exceeds the odometer's mechanical limits, or that it is not the actual mileage.

Older vehicles are exempt from the disclosure requirement past a certain age, on the reasoning that mileage stops being the dominant value driver on a vehicle of significant age.

The exemption period has been extended for newer model years, so the age at which a vehicle becomes exempt depends on when it was built. Certain vehicle classes are also treated differently. Check the rule that applies to the specific vehicle and state rather than assuming a single cutoff.

Rolling back an odometer is among the most direct forms of used vehicle fraud, because it converts straight into price. A lower reading commands more money and disguises how much service the vehicle is due.

The damage is not only financial. A buyer who believes a car has covered far fewer miles than it has will defer maintenance that is genuinely overdue — timing components, transmission service, suspension wear — on the reasonable basis that it is not needed yet.

A persistent belief holds that mechanical odometers could be wound back but digital ones cannot. It is not true, and acting on it is a good way to be defrauded.

A digital reading is a number in electronic memory. Equipment to alter it exists and is not difficult to obtain. In some respects digital tampering is harder to detect than mechanical, because a wound-back mechanical odometer often leaves physical traces — misaligned digits, scratches around the cluster — while an altered digital reading leaves the dashboard looking untouched.

1. 1Check mileage recorded at previous title transfersReadings are captured at each transfer and reported into the national title system. A sequence that goes down, or barely moves across years, is the clearest evidence available.
2. 2Read every service invoiceShops record mileage on each job. A consistent upward progression across years is strong corroboration; a gap or a reversal is not.
3. 3Check inspection and emissions recordsStates that run periodic inspections capture mileage each time, giving another dated series.
4. 4Look at the wear itemsPedal rubbers, steering wheel, driver's seat bolster, gear selector and door handle wear all tell you roughly how much use the car has had.
5. 5Check the tires and brakes against the storyOriginal tires with plenty of tread on a car claiming very high mileage, or four new tires on a car claiming very low mileage, both deserve a question.
6. 6Look at the cluster itselfMisaligned digits, scratches around the bezel, screws that have been turned, or a cluster that looks newer than the interior around it.

A discrepancy is not automatically fraud. Clusters get replaced after failures, readings get mistyped on paperwork, and trip meters get recorded on titles by mistake. But it is always a question that needs an answer before you buy.

• Ask the seller directly and ask for documentation of any cluster replacement
• Compare the discrepancy against the service file to see where the divergence starts
• Treat a reading that has gone down over time as decisive rather than ambiguous
• Check whether the title carries a not-actual-mileage brand already
• Walk away rather than talk yourself into an explanation the paperwork does not support

Where mileage cannot be established, price the vehicle as though the mileage is unknown — because it is. Odometer brands are permanent, and a car carrying one is worth materially less for the rest of its life.

Clusters fail, and replacing one is legitimate repair work. What matters is how it was handled afterwards, because a replacement cluster starts from its own reading rather than the vehicle's true total.

Done properly, the repair is documented, the true mileage is recorded, and where required a sticker is affixed noting the original reading and the date of replacement. Done improperly — or deliberately — it becomes an untraceable mileage reset.

• Ask whether the cluster has ever been replaced, and when
• Ask for the repair invoice showing the reading at the time
• Look for a mileage sticker in the door jamb or on the cluster
• Check whether the title carries a corresponding disclosure
• Treat an undocumented replacement as an unknown-mileage vehicle