How to create exact-size (50 GB, 100 GB, 200 GB...) partitions for Windows 10

So you want to see a round number when you open the file explorer because for some unexplainable reason it gives you inner peace? Well, to each their own I guess!

TL; DR formula:

(X + 0.566) x 1024 = Y MB

Where X = the partition size you want, and the result is in MB because the installer prompts to enter the size in MB and not GB.

So, the explanation for this formula is that you have to do is take into account the fact that the Windows 10 installer creates several small, hidden partitions when you're partitioning your hard drive, so when you enter the partition size you desire, the installer takes some of that size for its own small system partitions, and that's way it was difficult to calculate a round number for the partition size.

What you should do instead is that, during the installation, when you have enter the partition size, you're going to sum the size of the system partitions in the total amount.

For this, just keep in mind that Windows 10 creates 3 system partitions with the following sizes: 450 MB, 100 MB and 16 MB = 566 MB

Now, if you want, let's say, a 200 GB partition, you need to include the additional system partitions for a total of 200.5660 GB.

Last but nos least, the installer needs you to enter the size in MB. Since 1 GB is actually 1024 MB, you have to multiply:

200.5660 x 1024 = 205,379.584 or 205,380

And that's the value you need to enter during the installation in orden to have a round 200 GB partition.

Let me know in the comments if this worked for you!