How Accurate Are Fitbit Calories Burned?


Fitbit is one of the several activity trackers that has helped many people improve their health and fitness. With this gadget, the size of a bracelet, you can view real-time calorie loss data and learn what to adjust in your exercise routine. Unfortunately, it’s not always clear to users whether the data their Fitbit displays are accurate.

The most important thing to note about Fitbit’s calories burned data is that it’s sometimes inaccurate. However, don’t just discard your Fitbit based on this fact alone. Instead, consider factors determining the degree of accuracy of your Fitbit before you conclude.

This article discusses several of these factors and helps you learn if you can trust your Fitbit’s calories burned information.

Overview of Fitbit Calories Burned

The simple truth is that Fitbit calories burned tends to be an estimated forecast and not the actual number. But, even with this knowledge, you can still trust that Fitbit’s calculation of calories burned compares well to other activity trackers.

Generally, your Fitbit calculates two types of calories burned. The first is BMR calories, and the other is calories burned through exercise. BMR calories refer to those you burn when you perform basic life-sustaining activities. As the name suggests, exercise calories refer to those your body burns when you perform target calorie-burning activities.

The primary data that accounts for your Fitbit’s calculation of your calories burned include:

  • Running
  • Steps
  • Floors
  • Heart-rate
  • Sleep

The above standard data, your BMR, and any other manually input data create the basis of your Fitbit calories burned. Even though there is potential for error, especially when your profile has inaccurate data, Fitbit calories burned is a helpful guide in planning weight and fitness goals.

How Does Fitbit Calculate Calories Burned?

How Fitbit calculates calories burned is an essential consideration in the gadget’s accuracy. First, the methods highlight areas likely for potential errors. Second, you can judge whether the data feels like a genuine reflection of calories burned depending on your activities on a particular day.

Method #1: Using Basal Metabolic Rate (BMR) Data

As earlier mentioned, BMR is the rate your body burns calories without any exercise. BMR data depends on gender, age, height, and weight. For this reason, it will vary from person to person. Using BMR data is one of the significant reasons Fitbit calories burned is generally inaccurate.

First, Fitbit’s algorithm does not account for differences in fitness for people under the same BMR category. For example, if you exercise daily but are the same age and weight as someone who doesn’t, your metabolism will differ. Even though Fitbit puts you in the same BMR category, there should be a difference in total calories burned when considering BMR data.

Another area for potential error is when you input inaccurate data in your BMR profile. Fitbit’s estimation of calories burned will be based on wrong information and, therefore, inaccurate if you don’t input the correct data.

Method #2: Using Exercise and Movement

In addition to BMR, Fitbit also tracks your movement, heart rate, and exercise. Generally, Fitbit calculates energy expenditure from movement and exercise then quantifies how many calories you have burned. Even with advanced technology like Fitbit’s algorithm, it’s still difficult to estimate motion accurately. 

For example, it’s common for Fitbit to register movement even when you are just moving the gadget along your wrist. Based on that alone, the total tally of Fitbit calories burned will be inaccurate because fiddling with the device is not an actual movement.

Additionally, Fitbit over or underestimates energy expenditure depending on the particular movement. Several research studies show that Fitbit tends to be accurate when estimating calories burned when running but not when walking. The final number of total calories burned will be entirely inaccurate if the two movements are incorporated.

Is It Possible To Know the Exact Number of Calories Burned?

As earlier noted, Fitbit uses both your BMR data and movement estimation to calculate calories burned. As highlighted in this article, both methods have many loopholes that lead to data inaccuracies. Until there are other technological advancements in activity tracking gadgets, these loopholes will only improve to a small extent.

But, it’s essential to remember that Fitbit cannot capture or interpret this data with the same accuracy as laboratory equipment. For this reason, it’s impossible to know the exact number of calories burned with Fitbit.

To improve your chances of accurate estimation, ensure that the BMR data profile is as accurate as possible. After, you can use personal judgment to gauge the accuracy of your total Fitbit calories burned.


As you have learned from this article, Fitbit calories burned is not entirely accurate. But, you should note that there are still several benefits to using a Fitbit. First, it will keep you motivated and make exercising more enjoyable. Additionally, even though Fitbit does not display the exact data, it will still give a reasonable estimate of calories burned. You can improve or adjust your exercise routine to best suit your fitness goals.

Frequently Asked Questions

Should I Still Use a Fitbit Even if Its Estimation of Calories Burned Is Inaccurate?

Yes, you can still use a Fitbit to see how many calories you have burned in a day. Remember that maintaining a proper exercise routine can be an uphill task. Fitbit’s various features can make exercising more manageable and fun, helping you keep track of your fitness goals.

How Does Fitbit Compare to Other Brands?

After learning that Fitbit calories burned are inaccurate in some instances, you may be tempted to switch to another brand. The truth is that no fitness tracker is accurate in estimating calories burned. Other activity trackers overestimate up to fifty percent, making them grossly inaccurate.

Are All Fitbits the Same in Estimating Calories Burned?

No, some have fewer error percentages than others. While some Fitbits have a higher degree of accuracy when calculating calories burned, it’s essential to note that none is perfect. The best thing is to treat the number of calories burned as a baseline and not the actual number.

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