Odometer Hours Vs Miles

An odometer can’t tell a car shopper how many hours the engine has been running.

Odometers, either mechanical or electronic, keep track of the amount of miles a car travels. But a car’s odometer cannot tell how many hours the engine has run. The two are completely different indicators, depending on how the vehicle was used.


Each time a wheel rotates it moves part of a mile.

According to 2CarPros.com, odometers have been in existence since 27 B.C., when a Roman writer and architect used a chariot wheel to measure distance. Odometers work by measuring the wheel rotations on a vehicle and, depending on the size of the wheel, converting the amount of rotations to distance traveled. When enough rotations are added together, the car has traveled a mile and the odometer records that.

Engine Hours

Engine hours are calculated by how much time the engine has been running.

A vehicle’s engine hours are calculated not by miles, but by time. A vehicle that travels 60 miles can travel that distance in any amount of time. If the vehicle is traveling an average of 30 miles per hour, it will run the engine two hours to cover the distance. If the car is traveling at 60 mph, the car will cover the distance in just an hour.

What That Means

Running an engine long or running an engine hard have adverse effects on the mechanics.

Cars or trucks that sit in traffic, in idle, or at low speeds for long periods of time, will undergo more mechanical wear due to sheer hours of operation. The same holds true for engines that take a lot of highway driving, averaging speeds of 75 miles an hour. The engine works longer in the first scenario and harder in the second. Both affect the mechanicals of the engine.

Hours vs. Miles

A car with an odometer reading of 60,000 miles can have an engine that has experienced a wide variety of usage hours. One vehicle could have really low engine hours but has worked really hard to accrue those miles, moving during most trips at 75 mph. Another vehicle can sit in idle a lot, racking up high engine hours while covering the same distance. A third car, with a good balance of highway and city driving, will experience engine hours somewhere in the middle.