Deleting tons of duplicate contacts in your android smartphone is very stressful and time consuming, that is why google has added a powerful feature to the android Operating System (OS) that will allow or enable you merge duplicate contacts on your android smartphone just by a single tap.
How To Automatically Merge Duplicate Contacts in Android smartphone
Android's stock smartphone application should be the first thing to try. Go to your Contacts. I tried this on LG and Samsung phones, but depending on your phone's brand it can be a little different on the app,- Tap the Menu button.
- Manage Contacts.
- Then select Merge.
A screen with all repeated contacts will show up, so you can confirm which you want to merge one by one.