Previously we have written about how to delete duplicated contacts. Today we will introduce another feature you may not notice: Back up and Restore in Contacts. 

If you have a backup for your Contacts:

• You could restore all contacts on any iPhone.

• You could restore contacts again if you lose it accidentally.

Download and install the latest 3uTools. Click "iDevice" → "Data", you will see as below and you could manage Data in your iPhone on this page. 

Please ensure your "Contacts" on iCloud is closed. If closed, you can ignore this step, if not, just follow the screenshot to close it.

You can choose to back up any format you want: 

Connect the iOS device you want to restore contacts in 3uTools, and click restore.

If you have an Android device, you could read this.

And then 3uTools will restore the contacts to your another device automatically.