How do I move my iPhone contacts to Gmail?
Since end of 2012, Google has ended support for the Exchange protocol, so you would not be able to sync your iPhone contacts with your Gmail account via Exchange. Instead use the Gmail account method directly via Settings > Mail, Contacts, Calendars > Add account... > Gmail, enter your Gmail account credentials and enable contact sync. 

You can alternatively export your iPhone contacts to your computer to a single vCard file and then import the contacts file to your Gmail account.