partition doesn't match the size I specified it to be

Question

I created a disk partition on my USB with the size of 100MB. I used fdisk and mkfs commands.

I noticed that the size of partition isn't actually 100MB, but 104.9MB. I am wondering, why partition doesn't match the size I told it to be?

Answer 1

It's because of different units.

1 MiB (Mebibyte) = 1,048,576 B (Bytes) (2^20 Bytes)

In your case 100 MiB = 104857600 B ≈ 104.9 MB.