I have an existing account but I broke my fitbit and bought a new one. How do I sync my new one to my account?

No, you do not necessarily need a cell phone to use a Fitbit Inspire. While syncing the Fitbit with a smartphone can enhance its functionality by allowing you to receive notifications and track your data more comprehensively, you can still use the Fitbit Inspire without a smartphone.
To set up and use your Fitbit Inspire, you can follow these general steps:

1. Charge your Fitbit: Plug your charging cable into a USB port or wall adapter and connect it to the charging port on the back of your Fitbit Inspire. Charge it fully before you start using it.
2. Create a Fitbit account: If you don't have one, you will need to create a Fitbit account. You can do this on the Fitbit website or through the Fitbit app on a smartphone or tablet.
3. Set up your Fitbit: Follow the on-screen instructions on your Fitbit device or the Fitbit app to set up your device. This typically involves connecting your Fitbit to your Fitbit account.
4. Wear your Fitbit: Put on your Fitbit Inspire and start tracking your activity, sleep, and other metrics.
5. Sync with your phone or computer (optional): If you have a smartphone or a computer with Bluetooth capabilities, you can sync your Fitbit data with the Fitbit app or Fitbit website to see your stats, set goals, and track your progress more comprehensively.

clearing wont do it need to cancel sync/ account and you need to sync open account

You will have to Go to Settings> Bluetooth and turn Bluetooth off and back on. Open the Fitbit app. If your Fitbit device didn’t sync, restart it. If your Fitbit device won’t sync after your reinstall the app, log in to your Fitbit account on a different phone, tablet or computer and try to sync

You need to make account first then sync your Fitbit to your account

Bring your charged fitbit near to the plugged-in dongle or base station. You may need to press your fitbit button or tap it to wake it up. Then, Click the Fitbit Connect icon. Finally, Click Open Main Menu, and then click Sync Now. You may be asked to sign in, after which your fitbit should sync with your account.

just pull battery back out and place battery back in and then reconnect it to app. If it is similar to fit bit zip there is a limited time frame to re connect it to app once battery inserted.

https://help.fitbit.com/customer/portal/articles/183855-can-i-use-multiple-trackers-with-one-account-

http://www.quora.com/Fitbit/Can-one-Fitbit-base-sync-two-Fitbits-linked-to-separate-accounts

http://www.myfitnesspal.com/topics/show/1221397-multiple-fit-bit-products-one-computer

1. Go tohttp://www.fitbit.com/setup/and click theDownload Herebutton to download Fitbit Connect for your Force, Flex, One, or Zip tracker. If you have an Ultra, you should instead followthese steps.
2. Once the download has completed, open the file and begin to follow the onscreen instructions.
   If you are on a Mac, open the dmg file. If it doesn't appear on your desktop, search for "Fitbit Connect" in Spotlight.
   If you are on a PC, run the .exe file from your download location. If it doesn't appear on your desktop, search for "Fitbit Connect" in the Start menu.
3. Once the installation is complete, you will be presented with the Fitbit Connect Main Menu. SelectSet Up A New Fitbit Device.
4. Account Setup:
   • SelectNew to Fitbitif you don't already have a Fitbit.com account.
   • SelectExisting Userto log in using your existing Fitbit.com account.
   • ou will be asked for a few details about yourself. This information improves the accuracy of your caloric burn and distance data. You can later adjust yourprivacy settingsto control which details are shared with others.
   • After filling out your personal information, you'll be asked which device you're setting up. Select the appropriate tracker to continue.
   • Plug the wireless USB sync dongle into your computer (this is the smaller USB device--not the charging cable), and bring your tracker near to it to begin pairing.
   • Tracker Pairing:
     • Force, One, or Zip: You will see a pairing number that appears on your tracker's display once your device has been located; enter this number on your computer.
     • Flex: Follow the onscreen instructions and rapidly tap the device when instructed, then confirm its vibration.
   • After clickingNext, your tracker will connect to your Fitbit.com account. This can take up to a minute.
   • Once your tracker has connected to Fitbit.com, you may be prompted to enter a greeting (depending on which tracker you have). This can be your name or any 8-character combination of letters or numbers.
   • When your tracker is linked with your Fitbit account, Fitbit Connect will notify you and present some basic instructions on using your device.
   • You can now log into your account dashboard to view your synced data.
     You will not need to repeat these steps once they have completed--you can simply login tohttp://fitbit.comto access your dashboard.Or Still having Problem Then follow Us For
     HP Support

You must use the app or Fitbit Connect to set it up. The Bluetooth settings screen on the phone or computer will not work.