Fitbit devices encourage movement and wellness, but just how accurate is Fitbit calories burned and other data? Learn how Fitbit tracks these stats and how you can aid in more precise logging.

How Does Fitbit Track Calories Burned and Steps Taken?

Fitbit uses a three-axis accelerometer to sense motion.

A proprietary counting algorithm looks for specific movement patterns captured by the accelerometer to log everything from steps taken to distance, exertion and intensity levels, and sleep quality.

As for how Fitbit calculates calories burned, it uses your basal metabolic rate (BMR), a figure that measures how you burn calories while resting, and logged activity data.

How Accurate Is Fitbit Calories Burned?

The general consensus is that Fitbits are accurate, but they’re not perfect.

Several factors can influence over- or undercounting steps taken, including:

• Overcounting factors: Driving or riding on a bumpy road
• Undercounting factors: Activities that don’t require active arm swinging, such as pushing a stroller or shopping cart

According to a study on Fitbit accuracy published by the NCBI, researchers found that Fitbit devices were “acceptably accurate” for step counting about 50 percent of the time.

Additionally, they found that accuracy increased depending on where the device is worn:

• Wrist: For jogging, wrist placement was the most accurate.
• Torso: For normal-paced walking, wearing the Fitbit on the torso provides the most accurate measurements.
• Ankle: For slow or very slow walking, placing it on the ankle provided the best accuracy.

On the other hand, Fitbits aren’t great at calculating calories burned or workout intensity.

They tend to overestimate higher-intensity activities while underestimating distance traveled with fast walking.

But for sleep tracking, Fitbit devices were on par with research-grade accelerometers—in other words, accurate.

How to Increase the Accuracy of Your Fitbit

If you’re concerned your Fitbit isn’t tracking your activity correctly, or you want to ensure the most accurate results, here are the steps you can take to help increase the accuracy of your Fitbit.

Wear Your Device Correctly

Where and how you wear your Fitbit can impact accuracy.

In general, the device should remain in close contact with your body when you’re exercising (and not dangling from a necklace, backpack, or loose clothing).

Here’s what Fitbit recommends:

• For wrist-based Fitbits: Wear your Fitbit watch on top of your wrist, not too tight or too loose.
• For devices that track heart rate: Make sure it’s touching your skin, and wear it a bit tighter on your wrist when working out.
• For clip-based Fitbits: Wear the device close to the body. Secure the clip tightly to clothing with the screen facing outward.

Change Your App Settings

Fitbit relies on the information you provide in the app to calculate your steps and daily activity accurately.

Make sure the following settings are set up correctly in the app from Device Settings or account Settings.

• Wrist orientation: Make sure your device is set to the preferred wrist. By default, Fitbit uses the the left hand, the non-dominant hand for most people.
• Height: Fitbit uses height to estimate your walking and running stride lengths. Enter your correct height in inches or centimeters to ensure the most accurate step count.
• Stride Length: Fitbit uses a default stride setting based on your height. For greater accuracy, manually enter your stride length.
• Exercise App: To better measure workout intensity, use Fitbit’s exercise app (particular models only) to track your workouts, especially for activities like spinning or yoga.
• Use the GPS: If you’re not swinging your arms when walking (for example, when pushing a stroller), you can use Fitbit’s GPS feature to calculate your daily activity better (specific models only).

Change Where You Wear Your Fitbit

Based on the research, you can potentially increase your Fitbit’s accuracy by changing the location of where you wear your Fitbit during certain activities.

• Walking: Wear clip models on your torso for moderate paces or on your ankle when walking slowly.
• Jogging and running: Wrist-based models worn on the wrist provide the most accuracy.
• Sleeping: Fitbit suggests wearing a classic wristband (wrist models).