How Accurate is Garmin Fenix 5 Calorie Count?

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There are several fitness trackers and even fitness apps out there that help many people manage or lose their weight. Everyone is using a different fitness tracker that’s based on affordability and interests. Which fitness tracker are you using? How do you even know that the calories burned that is estimated by your fitness tracker are accurate for your workouts?
Have you ever tried using different fitness trackers when performing a workout to see if there might be any conflicting estimation from the two devices? If you have done so, then that can be the reason as to why you are reading this article. You can also be reading this article out of curiosity, which is also useful in this case. Regardless of your situation, in this article, we are going to discuss how accurate is Garmin Fenix 5 calorie count and perhaps also talk about other tracking devices.
I hope you will enjoy reading this article! Let’s dive in.

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Different Fitness Trackers provide conflicting Calorie Count

The main reason that has triggered this discussion is that each time you decide to perform a specific workout, and you have two different trackers on, you will be surprised if not shocked by their conflicting calorie count estimation. Your main worry must be the inability to answer the question, which fitness tracker is more accurate and which one is not so accurate?

Well, this will be a difficult discussion since it is also not easy deciding on which fitness tracking device is more accurate than the other, but since our main point of discussion is limited to Garmin 5, we will talk more about that than its rivals.

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The gap in differences in calorie count estimation among top Fitness Trackers

Well, when you decide to have a Google fit on and perform a workout, the results will be downright outlandish. This tracking device will always estimate that you have burnt a cool 200 calories more than what you will see in the Garmin Fenix 5s or Samsung Gear Sport. You will also notice a very big gap in calorie count estimation between the Garmin Fenix 5 and the Gear Sport, with the Garmin Fenix 5 having a higher estimation than the Gear Sport. When looking at the Fitbit Blaze estimation, you will notice a lower estimate compared to other fitness tracking devices.

The question now remains, who is right, and who is wrong?

Fitness Trackers Accuracy Test Results

There is a test that was carried out by Stanford Medicine to determine the accuracy of seven different fitness trackers. These fitness trackers are not limited to:

· Apple watch

· Fitbit Surge

· Basic Peak

· Microsoft Band

· Mio Alpha 2

· PulseOn

· Samsung Gear S2

You must have noticed that our pick is missing from the list of the fitness tracking devices that we tested to determine their accuracy. That’s bad news.

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The study revealed that the fitness trackers performed so well in determining the heart rate, more so during cycling that only had an average error of slightly 1.8%. Well, going further, the result wasn’t good. When walking, the fitness trackers had a less accurate average calorie count estimation of about 5.5%. All other estimations were almost accurate, just like the heart rate.

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Narrowing down to the fitness tracking devices, the Fitbit Surge performed so well in calorie burn, known as energy expenditure (EE) test. The estimated error for the EE was 27.4%. The PulseOn was far off by about 92.6% in the study. What you should note is that the lowest relative error for all the fitness tracking devices was for walking and running and the worst result for the rest calories. You should also know that the heart rate’s error rate was more in males than that of females.

Click this affiliate link to get your Garmin Fenix 5.

This Stanford study didn’t talk about the Garmin Fenix 5, but it helps point out the bigger discrepancies between calorie count estimation in fitness trackers. You realized that there is almost no problem with the heart rate estimation but a major fallback in the calorie count estimation.

How to Calculate Calorie Burn to that of Garmin Fenix 5

Here, we are going to try to determine how accurate Garmin Fenix 5 may be. This won’t be that easy because you will have to do some math. You will also need to understand what MET is. Its definition is the ratio of calories burned per hour when you are at work or walking, running, chopping wood, washing dishes, and other activities to your metabolic rate when you are sitting or sleeping. You should keep in mind that every activity has a unique MET value, and that’s what is used in the calculation to help determine how many calories you have burnt.

Fitness trackers also use this method in their algorithms to help estimate energy expenditure (calorie burn), and they also use other factors to determine greater or lesser degrees. For example, when you sit, that’s a value of one MET. This means that you will burn about 1 calorie per kilogram of weight every hour. So, let’s assume that you weigh about 145 pounds (66kg), you will burn while at rest 66 calories every hour. Other activities that you may tend to perform are more likely to have a higher MET value than 1 since you are using more energy to perform that activity, unlike when you are sitting.

Do you know the MET value for each of the activities you want to perform? If so, you can just add that into this equation. MET value * weight in kg = calories burnt per hour. Are you worried about finding the MET value for all the activities you want to perform? You can find all the MET values for all activities by visiting the Compendium of Physical Activities site. You will notice that whenever you hover over Activity Categories available in the top menu, a list of different activities appears.

Back to Garmin Fenix 5, for example, I walked for about 40 minutes and the Garmin Fenix 5 I was wearing estimated a calorie burn of 241. This will make my maths to be a little complicated because the equation above is for 60 minutes, but I only walked for 40 minutes. This will force me to divide the calculation by 1.5 because 60 minutes, when divided by 40 you find 1.5. If I could choose to walk for 30 minutes, I would divide the result from the equation by two.

So, to calculate my calorie estimation, we use this:

MET Value*weight in kg=calories burned per hour

4.3*66=283.8/1.5=189.2 calories (You shouldn’t forget that I have to divide by 1.5 because I walked for only 40 minutes, not 60 minutes. You should also know how much I weigh as mentioned earlier on. So, now you can compare how accurate the Garmin Fenix 5 was!

To make it easier for you, in this specific activity, I burned about 189.2 calories, while the Garmin Fenix 5 estimated that I burned 241 calories. That’s bringing us a difference of 23.

What is used to Calculate Calories on Garmin Smartwatches?

You need to keep in mind that these smartwatches share the same technology to carry out tasks. That means that regardless of your smartwatch, the calorie count is limited to the following order:

· Firstbeat – This will be calculated using the heart rate user profile data

To find more about the Firstbeat and the technology that is used in Garmin devices, you need to visit their website and choose your Garmin model: Firstbeat

· Fitness Equipment – This is calculated using the ANT and enabled fitness equipment

· Speed, Distance and User Profile – This is always calculated using the speed, distance, and user profile data such as height, weight, age, activity and any other variable.

Your fitness tracking device will usually decide on the appropriate method. This is what may cause the wide conflicting differences seen when different fitness tracking devices are tested.

How to Improve the Accuracy of Calories Burned in Garmin Smartwatches

Calories burned will always be determined by heart rate data, an accurate user profile and the kind of activity being performed. To make your calorie count as accurate as possible, you only have to do the following:

· You need to review your heart rate to make sure that it is being recorded accurately

· Review and make sure that your User Profile is accurate and has the exact information

· If you own a Vivoactive HR, Vivoactive 3, Vivoactive 3 Music, you should perform a one-time calibration that can be done by walking or running outside:

Just in the watch face, swipe to have a look at the My Day widget.

And proceed by choosing the danger icon and follow the instructions available on the screen.


The accuracy of calories burned in the Garmin Fenix 5 and several other Garmin smartwatches are slightly inaccurate. Using the equation provided, you can prove if your Garmin Fenix 5 is accurate in calorie burned estimation. Good luck!

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Luis Gillman
Luis Gillman

Hi, I Am Luis Gillman CA (SA), ACMA
I am a Chartered Accountant (SA) and CIMA (SA) and author of Due Diligence: A strategic and Financial Approach.

The book was published by Lexis Nexis on 2001. In 2010, I wrote the second edition. Much of this website is derived from these two books.

In addition I have published an article entitled the Link Between Due Diligence and Valautions.

Disclaimer: Whilst every effort has been made to ensure that the information published on this website is accurate, the author and owners of this website take no responsibility  for any loss or damage suffered as a result of relience upon the information contained therein.  Furthermore the bulk of the information is derived from information in 2018 and use therefore is at your on risk. In addition you should consult professional advice if required.