How to stop your phone from uploading your address book to Facebook

• Facebook has an opt-in feature that uploads all of your contact data to its servers.
• You can easily turn this feature off, and then delete all of your phone contacts stored on Facebook.
• Here's how to stop your phone from uploading your contacts to Facebook.

Whether you remember it or not, you may have once granted Facebook permission to store the contacts in your phone's address book. If you did, Facebook is continuously uploading these contacts to its servers.

You can find out if your phone is doing this, and stop it pretty easily.

Here's how to do that on Facebook for Android:

Todd Haselton | CNBC

• Open the Facebook app on your Android phone.
• Tap the menu button on the top right of the screen.
• Select "Settings & Privacy" near the bottom of the list.
• Select the "App Settings" option.
• Disable the "Continuous Contacts Upload" feature.

How to do it on Facebook for iPhone and iPad:

Todd Haselton | CNBC

• Tap the menu button in your iPhone or iPad Facebook app.
• Select Settings.
• Select Account Settings.
• Select General.
• Select "Upload contacts."
• Turn the option off.

How to remove contacts that have already been uploaded:

• First, make sure that you've followed the instructions above.
• Visit Facebook's contact management page from your web browser.
• Select "Remove all contacts."