Why is a 3.5 floppy diskette 1.44 MB and not 1.47 MB?

If you were to use the conventional base 2 or 1,024 KB 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 1.44 MB and not 1.47 MB? 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.