Your iPhone often contains dozens of contacts that need to be backed up to to your Gmail account. This process, dubbed "syncing" by Apple, is very quick and easy as long as you have an iPhone using version 3.0 or higher Operating System (iOS.) If you own an earlier version of the iPhone, install an updated operating system (3.0 or any later iOS) before you perform this contact sync.
Access the "Settings" menu on your iPhone.
Choose "Mail, Contacts, Calendars," followed by "Add Account."
Choose the "Gmail" icon from the list of email providers.
Enter your Gmail address in its entirety into the "Address" field.
Enter your Gmail password into the "Password" field. Touch "Next."
Enter the following phrase:
in the "Server" field. Touch "Next."
Touch "Delete Existing Contacts" when the iPhone prompts this action. While this action may seem contrary to the objective, it is a necessary part of the contact-syncing process. This will begin the backup process, and your iPhone contacts will be synced to Gmail shortly.
This process is necessary only once: In the future, your iPhone contacts will be automatically backed up to Gmail, as long as you have enabled "Push" on your iPhone.