How to Check Total Mileage on Car: A Complete Guide

June 13, 2024

An odometer measures the total distance a vehicle has travelled, displayed on the car’s dashboard. It is vital for assessing a vehicle’s usage and value, especially before purchase, as it indicates the wear and tear on critical components like the engine and transmission.

Types of Odometers

Mechanical Odometer

A mechanical odometer operates through a series of cogs and a drive cable connected to the car's transmission. Each cog represents a numerical digit, and the system starts counting from the right. Compared to electronic counterparts, mechanical odometers are less accurate and more prone to manipulation.

Electronic Odometer

An electronic odometer is digital and runs by the car’s electrical system. It uses a magnetic sensor to measure the gear rotation linked to the transmission. Electronic odometers are more accurate and tamper-resistant than mechanical ones.

Trip Odometer

Separate from the main odometer, a trip odometer can be reset to track the distance travelled over a specific period. This feature is especially useful for calculating gas mileage.

Reading and Interpreting Odometer Values

Mechanical Odometer

For mechanical odometers, the numbers may be slightly off-centre. It's important to periodically check for accuracy to ensure the odometer correctly reflects the mileage.

"Driven to Pi! (Odometer at 314,159 miles)" by mlhradio is licensed under CC BY-NC 2.0. To view a copy of this license, visit

Electronic Odometer

Displayed digitally on the dashboard, electronic odometers are easier to read and generally more precise.

Calculating Fuel Economy Using the Odometer

To calculate fuel economy, reset the trip odometer after filling up the tank. Record the miles driven and the gallons used during the next fill-up. Divide the number of miles by the gallons to find the average fuel economy (e.g., 200 miles driven on 10 gallons equals 20 mpg).

"Vespa LXV speedometer and odometer" by noradio is licensed under CC BY-NC 2.0. To view a copy of this license, visit

Potential for Odometer Errors

Mechanical odometers can be inaccurate, affecting vehicle resale value. Periodically verify that the odometer reading matches the actual distance driven. Faulty odometers should be repaired promptly to maintain the car's value and ensure accurate mileage recording.

Odometer Fraud ("Rolling Back")

Rolling back the odometer to display fewer miles is a dishonest practice. Although more challenging with electronic odometers, it is still possible through sophisticated methods. Be cautious of fraudulent practices when buying a used vehicle.

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