The most common reason your Fitbit won't sync is a broken connection between the device and your phone

Fitbit syncing fails when Bluetooth is off, the app is closed, or the device and phone are too far apart. The device itself may also need a restart, or the app may need to be reinstalled. Most of the time, one of these five fixes will restore the connection within minutes.

Before you try anything else, check that Bluetooth is turned on in your phone's settings. Then open the Fitbit app and leave it open while the device syncs — the app does not sync in the background on most phones. If the app is already open and Bluetooth is on, move closer to your phone. Fitbit devices need to be within 30 feet of your phone to sync.

Key Takeaways

  • Bluetooth must be on and the Fitbit app must be open for syncing to happen; the app does not sync when closed.
  • Restarting your Fitbit device clears temporary glitches and is the fastest fix when the connection is stuck.
  • Reinstalling the Fitbit app removes corrupted files that prevent syncing and usually works when restarts do not.
  • Fitbit devices need to be within 30 feet of your phone and should not be blocked by walls or metal objects during sync.
  • If your device is very old or the battery is critically low, syncing may fail even when everything else is set up correctly.

Restart your Fitbit device first

A restart clears the device's memory and stops stuck processes that block syncing. The method depends on which Fitbit model you own, but most devices restart by holding the button on the side or bottom for 10 to 15 seconds until you see the Fitbit logo on the screen.

For Fitbit Charge models, hold the button until the screen goes black and the logo appears. For Fitbit Inspire or Ace models, hold the button until you see a smiley face or the Fitbit logo. For Fitbit Versa or Sense smartwatches, swipe down from the top of the screen, tap Settings, scroll to About, and tap Restart. After the restart, open the Fitbit app and try syncing again.

Check your phone's Bluetooth and app settings

Bluetooth must be on for the device to connect. Go to your phone's Settings, find Bluetooth, and toggle it on. Then open the Fitbit app and wait 30 seconds for the app to search for your device. If the app does not find it, close the app completely and reopen it.

On Android, swipe up from the bottom of the screen to see your quick settings, or go to Settings and tap Connected Devices. On iPhone, go to Settings, tap Bluetooth, and make sure it is toggled on. If Bluetooth is already on, turn it off for 10 seconds, then turn it back on. This resets the Bluetooth connection and often fixes sync problems.

Reinstall the Fitbit app if restarting does not work

The app can develop corrupted files that prevent syncing even when your device and phone are set up correctly. Uninstalling and reinstalling the app removes these files and usually restores the connection.

On Android, go to Settings, tap Apps, find Fitbit, and tap Uninstall. On iPhone, press and hold the Fitbit app icon on your home screen, tap Remove App, and confirm. Then go to the Google Play Store or Apple App Store, search for Fitbit, and tap Install. Sign in with your Fitbit account and let the app search for your device. This process takes a few minutes but fixes most sync problems that restarts do not solve.

Forget the device and re-pair it in Bluetooth settings

Sometimes the Bluetooth pairing between your phone and Fitbit becomes corrupted. Removing the device from your phone's Bluetooth list and pairing it again can fix this.

On Android, go to Settings, tap Connected Devices, find your Fitbit device in the list, and tap the gear icon next to it. Tap Unpair or Forget. On iPhone, go to Settings, tap Bluetooth, find your Fitbit, and tap the info icon, then Forget This Device. Now open the Fitbit app and let it search for your device again. The app will guide you through re-pairing, which usually takes less than a minute.

Charge your Fitbit if the battery is very low

A device with a critically low battery may not have enough power to sync. Plug your Fitbit into its charging cable and let it charge for at least 15 minutes before trying to sync again.

Most Fitbit devices show a low battery warning on the screen or in the app before the battery dies completely. If your device has not synced in several days, the battery may have drained. Charge it fully and try syncing once it reaches at least 50 percent battery.

Update the Fitbit app and your device firmware

Outdated software on either your phone or your Fitbit can cause sync problems. Check that the Fitbit app is up to date by going to the Google Play Store or Apple App Store, searching for Fitbit, and tapping Update if an update is available.

Device firmware updates happen automatically when your Fitbit syncs with the app, so keeping the app updated usually keeps your device updated too. If you have not synced in a long time, the device may be waiting for a firmware update. Charge your device, open the Fitbit app, and let it sync completely. The update may take a few minutes.

Frequently Asked Questions

Why does my Fitbit sync sometimes but not other times?

Intermittent syncing usually means Bluetooth is turning off between syncs or the app is closing in the background. Make sure Bluetooth stays on and keep the Fitbit app open while syncing. If you have a lot of other apps running, close them to free up memory on your phone.

Can I sync my Fitbit without the app?

No, the Fitbit app is required to sync your device. You cannot sync through a web browser or any other method. The app must be installed and open on your phone for syncing to work.

What if my Fitbit is too old to sync?

Very old Fitbit models may not work with the current version of the app. Check the Fitbit website to see if your device model is still supported. If it is not, you may need to use an older version of the app, which you can find by searching your device model and "legacy app" online.

Does distance from my phone affect syncing?

Yes. Your Fitbit must be within 30 feet of your phone to sync. If you are too far away, move closer and try again. Walls and metal objects can also block the Bluetooth signal, so try syncing in an open area if you are near obstacles.

Will syncing work if my phone is in airplane mode?

No. Airplane mode turns off Bluetooth, which stops syncing. Turn off airplane mode before you try to sync your device.