How Accurate Is Garmin Calorie Burn?

These days, many fitness enthusiasts are using exercise and calorie-tracking devices to stay on top of their diets and workout regimens. 

How Accurate Is Garmin Calorie Burn

While these devices seem very useful on the surface, there are some questions concerning their reliability, and the fitness watches manufactured by Garmin are no different. 

Garmin produces many kinds of fitness watches, ranging from smartwatches to more simple activity trackers.

Most models have the ability to track the wearer’s activity and calorie burning throughout the day – but how accurate is this function? 

Read on to find out whether you can trust Garmin fitness devices to give you an accurate reading of your daily calorie burn total. 

What Is A Garmin Watch? 

How Accurate Is Garmin Calorie Burn

A Garmin watch is a wearable fitness device manufactured by Garmin.

Garmin manufactures many kinds of products, from fitness trackers to GPS devices, but the company is best known amongst runners and fitness enthusiasts for its range of fitness watches. 

The Garmin fitness range is called Garmin Forerunner, and it consists of a variety of lifestyle-tracking watches.

Most of these watches rely on GPS technology and are designed to allow runners to track their routes and sessions, including distance traveled and calories burned. 

How Does The Garmin Calorie Function Work? 

There are several watch models in the Garmin Forerunner range, and some work differently than others. However, here are the main methods that Garmin uses to track calorie burn: 

Speed And Distance Algorithm 

One of the most common algorithms used to track calorie burn across various fitness device brands is the speed/distance algorithm. 

This algorithm simply tracks how fast you are traveling and measures the time in which you do so.

It then uses your weight (manually entered into the device) to estimate how many calories you have burned. 

The key word here is ‘estimate’. The speed/distance algorithm is the simplest algorithm to use when there is no heart rate data (see below) to work with, but it’s also probably the least accurate.

This is because it ignores external factors such as whether you’re running up or down a steep incline – which obviously makes a lot of difference in terms of how many calories you burn.  

Heart Rate Algorithm 

A more accurate way of tracking calories burned through exercise is to use a heart rate algorithm.

Simply put, a person’s heart rate during exercise (barring other interfering factors such as heart condition) indicates how much effort they are putting into their workout.

From this, the calories being burned can be calculated. 

This calculation method does have its downsides, though. For one thing, there are many reasons why someone’s heart rate might rise that have nothing to do with exercise – an anxiety attack, for example.

While an elevated heart rate will cause more calories to be burned in general, an unrelated spike in your heart rate will not burn calories to the same degree as during a serious workout. 

Firstbeat Algorithm 

The firstbeat algorithm is arguably the most accurate method of measuring calories burned during exercise.

While it’s not perfect, it tracks more variables than other algorithms, which means that it’s the most likely to yield an accurate result. 

Firstbeat algorithm technology uses user-inputted data including weight, height, gender, and other relevant factors.

Then, this data is combined with the measured heart rate to estimate the calories burned. 

This algorithm comes in 2 generations: first and second. They are the same except that the first generation is less accurate because calculation methods have since evolved. 

New Leaf Testing 

You can also get a pretty accurate estimate of your calories burned using a New Leaf VO2 Testing Profile.

This method involves exercising while connected to wires that monitor your movements and heart rate.

This is specific to every sport, so your calories burned while running will be different to cycling, for example. 

Your profile can then be downloaded onto your Garmin fitness device so that you can track your calories for each workout you do. 


Your calorie burning rate can be calculated using a power meter, which measures kilojoules (energy) as a unit of how much work you’re putting into exercise.

This can then be translated into calories burned using an equation. 

Is The Garmin Calorie Function Accurate? 

How Accurate Is Garmin Calorie Burn

So, based on all the information provided above, will your Garmin fitness device give you an accurate number for how many calories you burn working out? 

First of all, it’s important to remember that devices using different methods of measuring active calories will yield different results.

This just goes to show that you shouldn’t obsess about the number on your calorie estimator.

While these calorie expenditure calculators can be useful guides, it’s unlikely that they will calculate the exact number of calories you have burned, no matter which method or device you use. The number on the display is just an estimate. 

With that being said, you can improve your chances of getting an accurate number on a daily basis if you choose a Garmin device that uses a more advanced calculation method.

While simpler devices that calculate calories burned based solely on speed/distance or heart rate might save you money, you may want to take these estimates with a pinch of salt.

Devices that base their estimates on second generation firstbeat algorithms or have the capacity to download New Leaf VO2 Testing Profiles may give you more accurate results. 

Compared to some other fitness devices on the market, Garmin’s calorie functions can definitely be considered accurate.

However, it’s ultimately a question of paying for the higher-end models for high-accuracy results. 

Final Thoughts 

It can be hard to determine actual calories burned during a workout, especially when you don’t fully trust the monitoring technology you’re using to track your activities. 

Luckily, Garmin has some wearable fitness devices in their Forerunner range that use advanced technology to produce accurate calorie metrics. 

Just remember that not all technology, including technology used within the Garmin Forerunner range, is created equal.

Some calculation methods, such as speed/distance, are less reliable than others, and you may have to invest in a more expensive product if you want an accurate calorie estimate.

Megan Rinzel
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