# Why can i store only 465 GB in 500 GB hard disk? [duplicate]

Possible Duplicate:
Why is the effective hard drive size lower than the actual size?

If one buys a 500 GB hard disk, why it shows only 465 GB. Where does the extra space go? Same for other secondary storage devices like pen drives. What is the reason?

-

## migrated from stackoverflow.comNov 27 '12 at 14:21

This question came from our site for professional and enthusiast programmers.

## marked as duplicate by Oliver Salzburg♦Nov 27 '12 at 14:51

1 kilobyte is actually 1024 bytes. So

500,000,000,000 / (1024*1024*1024) = 465.66 GB

To a hard disk manufacturer, one KB is 1000 bytes, one MB is 1000 KB, and one GB is 1000 MB. Essentially, if a hard disk is advertised as 500GB, it contains 500 * 1000 * 1000 * 1000 = 500,000,000,000 bytes of space.

However, manufacturers of RAM don’t sell it in even groups of 1000 – they use groups of 1024. When you’re buying memory, a KB is 1024 bytes, a MB is 1024 KB, and a GB is 1024 MB.

Unfortunately, Windows has always calculated hard drives as powers of 1024 while hard drive manufacturers use powers of 1000.

-
500 Marketing GByte (1000*1000*1000 bytes) = 465 Engineering GByte (1024*1024*1024) :-) – marc_s Nov 27 '12 at 14:26