It’s been rumoured for quite a while but we can now confirm that the PS5 comes with 667GB of usable storage. This can also alternate based on how the console is used. We’re not really sure what that means but the UI says that 85GB is reserved for “other”.
Astro’s Playroom also comes pre-installed on the console taking up another 11GB but this can be removed and re-downloaded at any time.
Given the fact that external hard drives don’t support PS5 games, and there’s no internal upgrade available at the moment, use this information however you will.