Difference Between Speedometer & Odometer (Including Trip Meter)

Everyone knows how important the instrument cluster is on any kind of vehicle because it contains all of the important instruments you need to look at depending on what you want to know regarding your vehicle.

In that regard, there are plenty of different instruments that may be confusing for beginners.

These instruments include the odometer, the speedometer, and the trip meter.

But what are the differences between these instruments?

A speedometer keeps track of the speed at which a car is moving at any given time. The odometer is the one responsible for keeping track of the vehicle’s total distance traveled throughout its entire lifetime and is non-resettable. Whereas, a trip meter is similar to an odometer but it only counts the distance traveled between trips and is resettable to zero ahead of a new trip. 

With how technology has been improving nowadays and how instrument clusters are now digitized, there are different instruments that can be found on a car.

While odometers and speedometers are not new because they have been around for decades, the trip meter is something that may be new to some people.

And that is why it is important to know what makes odometers and speedometers different from trip meters.

Odometer – measures distance traveled during the vehicle’s lifetime

One of the most important instruments that people look at when it comes to knowing how well the car is doing and whether or not it needs periodic maintenance is the odometer.

That’s because the odometer is the one responsible for keeping track of the total distance driven by a car in the sense that it tells you the car’s total mileage, which is what is most important when talking about how used the car is.

The odometer is also what people tend to look at when they are buying used cars from certain dealerships.

That’s because it will tell you exactly how old the car is in terms of the miles it has driven.

For example, a 10-year old car driven 30,000 miles may be considered to be in better shape compared to a five-year-old car that has been driven for more than 100,000 miles.

In short, you could see how banged up a car is just by looking at its total mileage using the odometer.

Now, if you are wondering how an odometer works, it really is based on the car’s wheels and on the rotations the wheels are making.

The more modern odometers have a magnetic or optical sensor attached to the transmission of a car to count how many times the toothed wheel on the transmission is moving.

However, the older mechanical odometers make use of an output shaft that is attached to the transmission and is also attached to the input shaft on the control panel through a cable.

So, what happens here is that the different mechanisms count the number of rotations the tires are making so that the odometer can calculate the distance the car has driven based on the rotations and on the car’s diameter.

In that sense, odometers are usually calibrated depending on the size of the car’s tires so that they can correctly estimate the car’s mileage.

Again, an odometer counts the car’s total mileage throughout its lifetime.

Due to how important the mileage is when it comes to selling a used car, the odometer is protected by law in such a way that tampering with it is illegal.

As such, the odometer should be counting the car’s mileage from the first day it was driven up to the point where it is going to be sold.

And throughout that period, the odometer should not be tampered with or altered in any way unless there is a good reason to replace it such as when it is damaged.

Speedometer – measures speed of a vehicle

Meanwhile, another one of the more common instruments that you can find in the car’s instrument cluster is the speedometer.

Unlike the odometer, which is not always used by the driver, the speedometer is one of the instruments that drivers often look at while they are driving because of how it plays an important role in everyday driving.

The importance of a speedometer is tied to the fact that this is the instrument that keeps track of how fast the car is going at any given moment.

This becomes important for safety reasons because you wouldn’t want to go too fast while you are driving in an area that tends to be accident-prone or has a speed limit.

And speaking of speed limits, you should also always keep an eye on your speedometer because there are speed limits placed by the law to protect the driver, the other drivers, and the pedestrians.

As such, you can see how important the speedometer is at any given moment.

That is why the speedometer is one of the instruments that is placed strategically such that the driver will always see how fast he is going while driving.

Most speedometers nowadays are digital in the sense that they will show you your car’s speed in a digital format flashed on your dashboard’s screen.

However, classic speedometers make use of gauges that will show you how fast you are going based on where the arrow on the gauge is pointing.

The speedometer works in a similar way to the odometer in the sense that it is also attached to the same mechanism that the odometer uses to keep track of your total mileage.

However, instead of calculating the distance, the car has driven, the speedometer uses the rotations that the wheel is making to calculate how fast the car is going based on how fast the tires are rotating.

This is where you will see the relationship between an odometer and a speedometer as they are similar in the sense that they use the same system.

Trip meter – measures distance traveled between trips

Not a lot of drivers actually know about the trip meter because not all cars have them.

However, while the trip meter seems to be something new in most of the newer cars we have today because of how easy it is to fit all of those different instruments in a digitized screen, this instrument has been around for a while already as there have been cars that make use of mechanical or analog trip meters.

Still, the trip meter isn’t something that you can commonly find in older cars because of how it doesn’t really have the same kind of importance as an odometer or a speedometer.

However, it can be quite useful depending on certain drivers who would want to know how far they have driven per trip.

That said, the purpose of a trip meter is similar to the odometer in the sense that it keeps track of the distance your car has driven.

However, a trip meter actually keeps track of trips such that it will count the distance you have driven per trip.

For example, if you designate today’s driving as one trip, the trip meter will count the total distance you have driven today regardless of where you may be going.

And if you want to count tomorrow as another trip, you can simply reset your trip meter so that the value goes back to zero and you can start an entirely new trip.

So, as mentioned, a trip meter can be reset to zero depending on the driver.

You can designate an entire week’s worth of driving as one trip and then reset it the next week so that you can tell how many miles you have driven this week in comparison to a different week.

There are also some trip meters that will show you how many miles you have left before your fuel runs out. In any case, the trip meter is mainly based on trips but still makes use of the same system and mechanism that your odometer uses.

For more information on the Trip meter reading issues please read this article.

Differences between odometer, speedometer, and trip meter 

The major differences between the odometer, speedometer, and trip meter can be seen in their purpose or functions.

Odometer vs Trip meter

Comparison between Odometer and Trip meter

OdometerTrip meter
The purpose of an odometer is to keep track of the car’s total mileage in the sense that it counts the total distance the car has driven throughout its lifetime. On the other hand, a trip meter keeps track of the distance your car has driven per trip and not throughout its lifetime.
Odometers are not supposed to be reset or tampered with because the law specifically states that you should never tamper with the odometer unless there are good reasons for you to do so.The major feature of a trip meter is that it can be reset back to zero if you want to start out a new trip.
Typically have six (999,999) digits.Typically have five or fewer (99,999) digits.
Odometer only shows the mileage traveled and clocks forward.Trip meters that can count two or more trips designated as Trip A, Trip B, and show averages.
Odometer is measured in miles or kilometers.Odometer is measured in miles or kilometers.

Speedometer vs Odometer

Comparison between Speedometer and Odometer

SpeedometerOdometer
The purpose of the speedometer keeps track of the speed at which your car is going.The purpose of an odometer is to keep track of the car’s total mileage in the sense that it counts the total distance the car has driven throughout its lifetime.
The speedometer resets to zero when the car comes to a complete stop and gradually increases as the car moves.The odometer stays on the latest count when the car stops and incrementally goes forward as the car moves
Speed is measured in Miles per hour or kilometers per hour.Distance is measured in Miles or Kilometers.
Powerful and fast cars have a Speedometer with larger reading which can go up to 800 miles/hour or 500 kilometers/hour. All cars usually have the same reading with a max of 6 digits (999,999).

Trip meter vs Speedometer

Comparison between the Trip meter and Speedometer

Trip meterSpeedometer
A trip meter keeps track of the distance your car has driven per trip and not throughout its lifetime.The purpose of the speedometer keeps track of the speed at which your car is going
The major feature of a trip meter is that it can be reset back to zero if you want to start out a new trip.The speedometer resets to zero when the car come to a complete stop and gradually increases as the car moves
Typically have five or fewer (99,999) digits.Powerful and fast cars have a Speedometer with larger reading which can go up to 800 miles/hour or 500 kilometers/hour.
Trip meters that can count two or more trips designated as Trip A, Trip B, and show trip averages.Speedometer only has one dial/reading but can show speed averages.
An odometer is measured in miles or kilometers.Speed is measured in Miles per hour or kilometers per hour.

Sources:

What is the difference between the odometer and trip meter?

Odometer vs. Trip meter. How does it work?