Mystere is correct.
I advise on a single drive to leave the whole drive as a single drive. Many years ago when space was a real premium it was different.
Invest in an external drive to back up your data. Or install a Secondary Drive as a Data Drive.
The reason for this is... even if you partition out the one drive, if it goes bad, you are going to lose it all anyway, so partitioning it out has very little benefit.
However, I am about to contradict myself, there is a slight benefit to partitioning a drive that size, but I would only split it in half (250/250), you do keep your data and OS separate by doing this.
On the other side though, if you are going to be doing backups (which you should, cause there are 2 class of PC users and data,, those who have lost data and those who WILL lose data), You would then just back up the whole drive, OS and all, then if you have to restore the entire drive for any reason, you can, as long as you have a good restore, and if you don't, you will still have the data backed up anyway. So, this eliminates the need to partition the drive into multiple drives. Which I rarely recommend these days.
Unless as stated, you will be multi-booting OS's.