While the PS4’s stock hard drive is 500GB, which actually means there will be 465GB available for standard devices, it appears that you’ll only be able to use 408GB of that system storage, with a picture posted to twitter showing 323GB available after approximately 85GB has been used.
So, just where has that extra 57GB got to? Could it be that the OS, when unpacked completely, partitions off 57GB of the hard drive space, for anything that might be required in the future? That does seem like a lot of space.
It’s not another game anyway, as the user posted a follow-up tweet showing that he only had three games installed, which amount to around 85GB after all.
Whatever the case, it appears as though you’ll only have around 400GB of space on your stock hard drive, so upgrading might be required sooner than you thought.