How does my Fitbit device calculate my daily activity?

Fitbit devices use a 3-axis accelerometer to count your steps. This sensor also allows your device to determine the frequency, duration, intensity, and patterns of your movement.

Fitbit devices use the formula below to calculate distance. Your stride length is determined by your height and sex.

Steps x Stride Length = Distance Traveled

When you track an activity with GPS, your device calculates your distance using GPS data rather than steps. If you begin moving before you get a GPS signal, your device calculates distance using your steps until GPS connects.

To update your stride length, track a run with GPS or measure your stride length manually. For more information, see Can I change my stride length in my Fitbit account?

Fitbit devices that count floors have an altimeter sensor that detects when you go up in elevation. Your device registers 1 floor when you climb about 10 feet or 3 meters. Your device uses changes in barometric pressure combined with the steps you take to calculate floors climbed. Fitbit devices don’t count floors on stationary exercise equipment, such as a StairMaster or treadmill, or when you go down a flight of steps.

Fitbit devices combine your basal metabolic rate (BMR)—the rate at which you burn calories at rest to maintain vital body functions (including breathing, blood circulation, and heartbeat)—and your activity data to estimate your calories burned. If your device tracks heart rate, your heart-rate data is also included, especially to estimate calories burned during exercise. The number you see on your Fitbit device is your total calories burned for the day.

Your BMR is based on the physical data you entered in to your Fitbit account (height, weight, sex, and age) and accounts for at least half the calories you burn in a day. Because your body burns calories even if you’re asleep or not moving, you see calories burned on your device when you wake up and will notice this number increase throughout the day.

Note that in certain regions, you see kilojoules instead of calories. To change your units of measurement, see How do I change the units of measurement in my Fitbit account?

• Make sure that you wear your device correctly, either on top of your wrist or in the clip. If you switch your device to your other wrist, update the Wrist setting in the Fitbit app. For more information, see How do I wear my Fitbit device?
  
• Confirm that the personal information you entered when you set up your Fitbit account (height, weight, sex, and age) is correct. For more information, see How do I manage my Fitbit profile?
• On certain devices, you can use the Exercise app to track your workouts and see your real-time heart-rate data. This data can better determine calories burned during exercise, especially for activities like spinning or yoga where your step count might not reflect your intensity level. For more information, see How do I track my workouts with my Fitbit device?
• For your device to count steps during a walk or run, your arm must swing back and forth as you move. If you need both hands (to push a stroller, for example), or if you hold a dog leash with the same arm that you wear your device on, consider using GPS to better calculate your distance traveled and calories burned. For more information, see How do I use GPS on my Fitbit device?

You can’t delete daily activity data. If you see extra steps or floors on your device, log a non-step-based activity, such as driving, to override them. For more information, see How do I add, edit, or delete Fitbit data and activities?

After you track a run with GPS, your stride length updates automatically. For best results, run at a comfortable pace for 10 minutes or more. For more information, see How do I use GPS on my Fitbit device?

You can also measure your stride length manually and add it to your Fitbit account.

How do I measure my stride length?

1. Go to a place where you're sure of the distance, such as a track.
2. Count your steps as you walk or run, making sure you travel at least 20 steps.
3. Divide the distance traveled (in yards or meters) by the number of steps you took to determine your stride length. If needed, convert your stride length into inches or centimeters.

How do I add my stride length to my Fitbit account?

Fitbit app

1. Tap the Today tab , and then tap Exercise days.
2. Tap MenuActivity settingsStride Length.
3. Adjust your stride length.

fitbit.com dashboard

1. From the fitbit.com dashboard, click the settings icon Settings.
2. Click Personal Info.
3. Under Advanced Settings, find Stride Length and click Edit.
4. Click Set Your Own and adjust your stride length.
5. Click Submit and sync your device.