I do not have a vanilla system to look at, but I have a fairly new company issued 13" Macbook Pro with a handful of company installed apps (think system resource sucking anti-virus, and similar). I have not stored much personal stuff on it.
This system is using 22GB. I suspect if the company stuff was not on this system, there would be somewhere under 20GB. This would be macOS and all the standard Apple apps that come with a new Mac.
So you should have at least 225GB of free space for your own use.