If you're logged into your phone with a google (android) or icloud (iphone) account, the chances are good that all of your contacts are backed up in the cloud already. [substeps] See back up an android phone on the google cloud for instructions on backing up your android contacts.
[header] How to delete cell phone memory [title] Back up your contacts. [step] Before wiping your phone, you may want to back up your contacts list. You'll be able to restore this list after you finish the reset procedure.