Why is a 3 1/2" floppy diskette 1.44MB and not 1.47MB?
If you were to use the conventional base 2 or 1,024KB to figure out the capacity of a floppy diskette size it would be 1,474,560 bytes.
1.44 * 1000 * 1024 = 1,474,560
So then why is a 3 1/2" floppy diskette 1.44MB and not 1.47MB? Because when the manufacturers first created the floppy diskette, they decided to divide by a base 10 or 1,000 value and not 1,024.
1.44 * 1000 * 1000 = 1,440,000
Although at the time this was not the conventional method of defining a disk space on a computer, this value persisted. This was one of the first of many confusions regarding disk space on computers.