How Accurate Are Fitness Trackers?

Fitness Trackers

Fitness trackers have become essential pieces for many people. These devices are portable and replace the need for a standalone watch, as they usually provide this functionality too.

One research paper explains that the market for fitness trackers reached a global value of $34.6 billion by the end of 2020. At the end of 2021, the market is expected to grow to a value of $41.3 billion.

While fitness trackers have become very popular in modern times, many people are questioning the accuracy of these devices. Some of the fitness trackers on the market do seem to provide accurate measurements on energy expenditure, steps taken, and even heart rate.

Unfortunately, this does not account for every fitness tracker out there. In this post, we consider how accurate these devices are, and look at which branded options are the most suitable options when buying a new tracker.

Typical Functions Of A Fitness Tracker And Their Accuracy

Fitness trackers come in quite a variety of designs – and each device has specific functions. Some of these devices are very limited in terms of functionality. This generally accounts for watches that are solely made to provide fitness tracking functionality.

There are also many of these trackers that offer additional features, such as the ability to synchronize the device with your smartphone. In this case, you’ll be presented with an opportunity to receive notifications on the watch, as well as text messages and sometimes even calls.

While these features can be very useful, it is important to consider the specific fitness tracking functions offered by the device.

Do not only look at the quantity of fitness tracking features, but also the accuracy. Even though there are different technologies, sensors, and methods used among the variety of fitness trackers that are available, these devices generally share a few features.

This relates to the specific data that they are able to track. We take a look at the most commonly used data measures that fitness trackers provide and how accurate they are in general.

Step Counting

One of the most common features that you will find in a fitness tracker is the ability to count your steps. In fact, step counting technology has become so common, your smartphone likely has the appropriate sensors as well.

While it can be useful to use your smartphone to count your steps, the data reported will likely not be as accurate as it should be. Additionally, people generally do not prefer to carry a smartphone with them when they start a workout – especially when running or jogging.

In this case, the use of a smartwatch or fitness tracker that counts your steps can be helpful.

In terms of accuracy, you’ll usually find that a watch tends to provide more accurate data compared to your smartphone’s built-in sensor.

One thing to take into consideration, however, is the fact that the quality of the sensors used affects the accuracy of the device’s ability to count steps. Thus, when determining how accurate the step counter in a specific watch would be, make sure you consider the brand and the specific device.

The watch should contain appropriate sensors as well – this is an essential part of ensuring the device can actually count every step you take.

There are a few publications that focus on providing more data regarding the accuracy of popular smartwatches and fitness trackers.

According to these reports, the Apple Watch currently exceeds in terms of counting steps, as well as when it comes to determining the total distance traveled.

When you are trying to determine if a specific watch is accurate, be sure to consider the setup process as well. The watch should ask you for a few basic measurements and personal details before it starts to count your steps.

This should include your weight and your height. Both of these factors can affect the distance you travel with each step. For example, a longer person tends to take bigger steps – and this needs to be taken into consideration when determining a specific number of steps that you have taken.

Heart Rate Monitor

Many of the fitness trackers on the market now starts to include a heart rate monitor, in addition to the sensors that help to pick up factors like distance traveled and steps taken.

The goal of these sensors is to give you a view of your current heart rate. Some fitness monitors will provide live heart rate tracking, while others may require the press of a button. Regardless, accuracy is a very important factor when looking at a heart rate monitoring function.

You will depend on this data for a number of reasons, especially if you have concerns regarding your cardiovascular health. When the data presented is not accurate, it makes it hard to keep track of your health.

It can be difficult to determine the accuracy of a heart rate monitor in a smartwatch. One of the most effective options is to compare the data to a medical device, as this can show you how much deviation there is with the heart rate monitor. There are also studies that have looked at how accurate a heart rate monitor in a smartwatch can be.

In one study, researchers found that there are a few smartwatches and fitness trackers that can provide relatively accurate data when tracking a person’s heart rate.

The accuracy, however, is not the same as a heart monitor that a patient can wear on their chest. Thus, it is important to note that you should not completely rely only on the heart rate provided by the fitness tracker. Use it as a guideline to help you determine when you are pushing your body too far, for example. You can also use the heart rate provided on the tracker to determine how efficient your current exercise is.

Calories Burnt

Apart from sensors that help to detect heart rate and steps taken, another important feature that some smartwatches offer is reading on calories burned. It is important to note that this is a feature that not all of these devices have.

Some devices will rather send data to your smartphone, where an app can then analyze the information to estimate your energy expenditure.

When you are looking to lose weight, this particular feature becomes essential. Most diets focus on creating a calorie deficit. This means your energy expenditure should exceed how many calories you eat on a daily basis. When the tracker shows you how many calories are burned, it makes the process of following a calorie deficit diet significantly easier.

The accuracy in estimating energy expenditure relies on a number of factors. There are no sensors that can actually tell you how many calories you have burned during an exercise session. Instead, software needs to be used to make a few calculations. Measuring heart rate and steps taken plays an important part here. The data helps with calculating calories burned.

If a device only uses the number of steps you have taken and the distance traveled, then it will not be able to provide you with accurate data. Your heart rate, as well as personal information, needs to be accounted for as well.

You should ensure the initial sync between the watch and your smartphone introduces you to a “setup wizard”. This usually consists of a few steps that you need to complete. Among these steps, you should ensure there is a form that asks you for some information – this should include your age, gender, height, and current weight.

To provide an accurate view of calories burned, all of the information listed above needs to be taken into consideration during the calculation.

How Accurate Are Top Rated Fitness Trackers

Researchers have performed multiple studies on these consumer devices. The data presented in these studies help people understand how useful their fitness devices truly are. 

Study On Fitness Tracker Accuracy

This brings us to one study, in particular, published in the JMR mHealth and uHealth Journal. The study looked at how these wrist-worn devices measure up to each other, with a focus on the following measurements:

  • Measuring heart rate
  • Measuring energy expenditure
  • The ability to measure sleep duration and quality
  • Distance traveled
  • Step count measuring

The study focused on comparing some of the biggest brand name watches that are currently on the market. The specific  commercial fitness trackers that formed part of the study consisted of the following:

  • Xiaomi Mi Band 2
  • Jawbone Up 3
  • Apple Watch 2
  • Samsung Gear 3
  • Fitbit Surge
  • Huawei Talk Band B3

During the study, the researchers asked participants to perform specific activities. This included sleeping and resting, walking, cycling, and running. Each person’s fitness level, weight, height, and other personal measurements were taken into consideration.

Following multiple tests, the researchers discovered that the Samsung Gear 3 seemed to be the most accurate among the devices that were compared. The other devices also provided accurate data, with the Apple Watch 2 closely following the results offered by the Samsung Gear 3.

There are other devices on the market as well, such as the Whoop Strap. While these were not included in this study, it does not necessarily mean they are less accurate.

How To Choose An Accurate Fitness Tracker

There are a couple of factors that you need to consider when looking for a fitness tracker that can provide you with accurate measurements. When looking for a fitness tracker, accuracy is not the only thing to consider either. Be sure to keep the following factors in mind when shopping for a fitness tracker:

  • Three of the main elements that make a good fitness tracker include its accuracy, the durability of the structure, and its features.
  • It’s usually a good idea to start your search by determining what brand you prefer. The major brands in the market tend to produce higher-quality fitness trackers, which can give you more peace of mind when it comes to accuracy.
  • There are scientific studies that have looked at the efficacy of popular options. These can also serve as useful guidelines to help you understand which option will be suitable for your needs.
  • Take any additional features you require into account, such as GPS and the ability to sync with your smartphone.
  • You should not overlook the important role that style plays too. This is a personal factor. Make sure you consider the type of watches you usually wear. Aim to find a tracker that can fit your current fashion preferences.

What To Avoid When Buying A Fitness Tracker

All of the advancements in technology have made it easier for manufacturers to produce fitness trackers. This has created a huge market for these devices. Unfortunately, this also means that the market is now flooding with devices that do not offer accurate results or fail to provide the functionality you require. When the tracker can’t give you accurate measurements on energy expenditure, or when measuring calories burned.

You should aim to avoid buying one of the cheap options on the market. Even though these may seem like a good option, they will generally end up as a disappointment. Many of the cheaper options on the market frequently lose their sync with your smartphone. The data presented will also usually be inaccurate and a large number of these lack a heart rate monitor.


A fitness tracker is a useful device for keeping track of your cardiovascular health, as well as exercise performance. They are used by people who want to lose weight and work on their fitness, as well as those who have concerns regarding their heart rate.

Not all of the fitness trackers on the market can produce accurate data. When looking to invest in a new one, be sure to consider the studies we looked at in this post. This will help you identify the best fitness trackers that can give you a more accurate overview of your performance and stats.