The big question is how do smartwatches measure calories burned? Is it accurate? Can you rely on the data shown by different wearables?

Smartwatches are becoming increasingly popular, and their popularity is only set to grow. Statistica estimates that the smartwatch shipments will increase to 253 million by 2025, up from 173 million in 2022.

They are another way to measure how many calories you burn, how many steps you take, how many hours you sleep, and more.

Few models even use GPS technology to help runners map their routes and make sure they’re hitting their goals.

Smartwatches help you track your daily activity, via the number of steps you take, distance cover and calories burned. Here’s how smartwatches track calories.

How Do Smartwatches Measure Calories Burned?

How Does a Smartwatch Detect Calorie Burn?

Step tracking

Your smartwatch counts every step you take using its built-in pedometer. A pedometer is an instrument for recording the distance travelled by a person on foot.

A pedometer works by counting a person’s steps, and may also measure the distance travelled. Pedometers record the number of steps taken, often in units of 1,000 (1 kilometre, or 0.62 miles).

Some models can track other measures such as heart rate or calories burned. It was invented in Japan in the 1970s by Dr Yoshiro Hatano and since then has been used more widely throughout Asia and Europe.

stecp tracking in smartwatch

Distance tracking

Distance is measured using GPS or AGPS (assisted GPS), which uses existing cellular networks to calculate your distance from known locations and triangulate your location based on those cells’ signals. Some smartwatches use both systems to help obtain a more accurate reading.

Calories burned and heart rate tracking

Most smartwatches will measure your heart rate using either an optical sensor or by using a light sensor that detects changes in blood flow near the skin surface as a result of underlying blood vessel contraction/expansion as your heartbeats.

Do smartwatches track calories burn? In order to accurately track calories burned, your watch needs to know two things: how many calories you burn each day and how much activity you’ve performed.

do smartwatches accurately track calories

If you don’t input this information into your watch, it won’t be able to accurately measure your daily calorie burn.

If you don’t have time to record all of your activities throughout the day, there are several apps available for smartwatches that can do it for you.

The best part is that these apps are free! However, they do require you to give them access to your phone information before they can accurately measure your activity throughout the day.

You can read our article which explains how does smartwatch work.

Why it is Important?

It’s important to know how many calories you burn in a day because the amount of calories you consume and the number of calories you burn each day needs to be equal.

If you consume more calories than what your body burns, then you will gain weight. If you consume fewer calories than what your body burns, then you will lose weight.

Losing weight is one of the most common reasons people purchase smartwatches. Smartwatches can help people keep track of how many calories they’re consuming in a day, as well as how many calories they’re burning by exercising.

This enables them to stay on top of their weight loss goals and make sure they don’t consume too many calories in a single day.

Most smartwatch brands can also track your heart rate, which is crucial for athletes or those who are very active. This way, if something goes wrong, they’ll be able to catch it early.

Smartwatch Calories Burning Accuracy

Do smartwatches accurately track calories? Although it does to a great extent, it isn’t entirely accurate for everyone.

If you’re someone who loves a workout that mixes up different types of exercise such as strength training then an accelerometer won’t accurately pick this up.

smartwatch calorie burn accuracy is debatable

If you have large wrists then you may find that there is too much movement for the smartwatch to accurately track your movements and therefore your calories burnt.

The only thing that you need to know about the calories burned is that no devices are 100% accurate for everyone. It depends on your size, weight, and the intensity of your workouts.

The best thing you can do is to take the average of all your activities and use that as a guide to keeping you on track. When it comes down to it, there are no smartwatches that are 100% effective with calorie tracking.

If they were, they would be able to tell you exactly how many calories you burn during a workout or day with 100% accuracy. However, fitness bands have better accuracy than smartwatches.

But if a watch could do this, the calories burned would depend on too many factors. For example, how much does someone weigh? How fast were their steps? How long were their strides? To what extent did their arms move? Etcetera!

So, smartwatch calories burned accuracy is where companies have a workaround.

How to Customize Your Calorie Burn to Your Activity Level & Goal?

You can customize your calorie burn to your activity level and goal. A good way to start is by figuring out which activity level is right for you. There are five different levels, based on how active you are:

  • Sedentary: Little or no exercise, desk job Lightly
  • Active: Light exercise or sports one to three days a week
  • Moderately active: Moderate exercise or sports three to five days a week
  • Very active: Hard exercise or sports six to seven days a week
  • Extremely active: Hard daily exercise or sports and physical job.
set your workout goal and track it using smartwatch

After you’ve figured out your activity level, take a look at your goals. If you’re trying to lose weight, focus on calories burned.

If you’re trying to maintain, focus on steps. Trying to gain weight? focus on calories in vs. calories burned.

A simple daily goal is to reach 10,000 steps. This is the minimum recommendation for adults who are at a healthy weight.

In order to lose weight, then you can set a more ambitious step goal. And if you’re trying to gain weight, aim for fewer steps per day.


Now you’ve got an idea of how smartwatches measure the calories burned. Since smartwatches were first introduced, there has been much debate surrounding how accurately they measure calories burned.

The bottom line is that there’s no way a smartwatch can accurately estimate calories burnt or heart rate since there’s so much human error and environmental variance involved.

Regardless of how your smartwatch collects this data, it is then processed by an algorithm that neatly spits out a figure representing the number of calories you have burned during your workout.

All in all, the smartwatch is a powerful tool for those on a fitness trek. All you have to do is keep yourself motivated enough to find the time and effort needed to maintain that healthy lifestyle.

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