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How Does Fitbit Calculate Calories Burned?

Fitbit calorie tracker explained

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Updated on January 8, 2021

The Fitbit calorie tracker feature can be useful when planning a diet or workout schedule. Here's how Fitbit calculates calories burned.

If you prefer to count kilojoules instead of calories, tap your profile image, then tap Advanced Settings > Units.

How Does Fitbit Calculate Calories Burned?

Calories are calculated using a variety of data provided by the user and information collected by the Fitbit tracker. Here’s what Fitbit uses to measure your daily calorie burn.

Basal Metabolic Rate (BMR)

Your BMR, or basal metabolic rate, is an estimate of how much energy your body uses while at rest, or when not performing any extraneous activity such as playing sports or running. Fitbit works out a rough estimate of your BMR by using the personal data you provided when filling out your profile such as your height, gender, weight, and age. Other information often used to determine a person’s BMR including breathing rate, blood pressure, and heart rate.

This BMR information is why your Fitbit app will show you burning calories even when you haven’t done any exercise and have just been lounging around watching Netflix or Disney+ all day. Your body is burning calories all of the time.

Calories Burned screen in the Windows 10 Fitbit app. — Fitbit

If you use a Fitbit Aria smart scale, your current weight will be automatically synced to your Fitbit profile each time you weigh yourself, so you won’t have to manually change it if you gain or lose weight.

Heart Rate

While Fitbit devices can’t measure your breathing rate and blood pressure, most Fitbit trackers that you wear on your wrist can measure your heart rate and will sync this data to your account to improve the calorie burn estimate. Generally, a higher heart rate means a faster metabolism while a slower heart rate implies that you’re burning calories at a slower rate.

Some examples of Fitbit trackers that can measure your heart rate include the Fitbit Ionic, Fitbit Blaze, Fitbit Versa, Fitbit Versa 2, Fitbit Charge 2, Fitbit Charge 3, and the Fitbit Inspire HR.

Daily Steps

All Fitbit trackers can record how many steps you take each day. Not only is this technology used to measure when you’re active, but it’s also helpful for detecting how much you don’t move.

Tracked Exercises

When you log activities in the Fitbit app, Fitbit will estimate the number of calories burned based on the type of activity and how long you were doing it. This number will be added to your daily total.

Logging exercises in the Fitbit apps can inflate the total number of calories burned because your profile will log both the BMR burn and the estimated exercise-related burn for that same time period.

How to Use the Fitbit Calorie Counter

The Fitbit apps for iOS, Android, and Windows include a calorie-counting feature, which lets you manually log food consumed throughout the day. This feature combines with the calorie burned feature to show you how many calories you’re consuming compared to how many calories you’ve burnt throughout the day.

To add Fitbit calorie counting to your app dashboard, go to Discover > Health & Fitness Stats > Food > Add to Today.