Here is another trick. Use of GiB or MiB or KiB instead of GB, MB, KB. The old terms are the correct ones, if you use the correctly. Kilo means 1000, not 1024. Just because computers use a base 2 system and it has remainin unused bits does not change the true meaning of the word.
Mega means 1 Million
Giga means 1 Billion.
You don't need to worry about the extra bits of data unless you are a programmer, then you can simply reference them mathematically.