If you sync iPhone contacts from multiple sources, such as iTunes, iCloud or Microsoft Exchange, duplicate contacts are likely stored on your device. While iOS doesn't include a way to merge these duplicates, third-party software can access your phone's address book and automatically find, merge, back up and delete duplicate contacts. These programs enable you to search for duplicates by name, number or email address, so you can find contacts with missing names or numbers when searching for duplicates.

Step 1

Open the App Store and search for duplicate contact-merging software, such as Cleaner, Remove Duplicate Contacts or Contact Manager (links in Resources), which all provide a similar interface with the ability to search, merge, back up and delete contacts sorted by various filters, including exact duplicates or contacts without names.

Step 2

Stop syncing iCloud and Microsoft Exchange contacts while removing duplicates. These services don't recognize each other and may cause duplicates to reappear after removal if they remain in sync during the process. Other services, such as Gmail and Yahoo, sync with all contacts in your address book rather than server-specific ones, so they don't cause this problem. To disable iCloud and Exchange contacts, tap “Settings,” choose “Mail, Contacts, Calendars,” select the account to disable and turn off the “Contacts” option.

Step 3

Launch the contact-merging software and select the “Duplicate Contact” filter from the menu screen. This option is the same in each application, although the filter's name may vary between programs. The software searches your iPhone's address book for contacts with identical data fields and displays them in a list.

Step 4

Select a contact from the list of contacts with duplicate entries to view a list of the discovered duplicates. Tap “Merge” or “Delete,” depending on the software you're using. The program deletes any unnecessary duplicates, leaving just one entry for the selected contact. You are returned to the screen listing all contacts found to have duplicate entries. Repeat this step for each contact on the list.

Step 5

Resume syncing iCloud and Microsoft Exchange contacts if you disabled them in Step 2. Tap “Settings,” choose “Mail, Contacts, Calendars,” select an account and turn on the “Contacts” option. These services now sync with the contacts stored on your device and don't create duplicates by transferring existing contacts. Your iPhone remains free of duplicates as long as you don't separately add the same contacts to iCloud and Microsoft Exchange from another device, such as a computer. This solution also applies to contacts synced with iTunes as iTunes doesn't transfer contacts that already exist on your device.