How to update my htc phone without losing contacts?

I want to update my phone but I don't want to lose my contacts. I've been told many different things. I tried using htc sync but I don't think its working. I also heard you can sync your contacts with your gmail account? I don't know how to. Can someone explain how to or another way to save my contacts somewhere? Something free safe and legit. Nothing that will cause a virus. Shanks(: