Your "total" contact number includes all contacts in your account, including those that are unsubscribed.
Your "subscribed" total excludes contacts that are unsubscribed. *
* It's important to note that your total subscribed number may not match your total reachable contacts. For more information on this, see Why does my audience number differ from the number of contacts actually sent to?
For more detail on contact statistics, see Contacts: Overview.