Formatting a new disk, lost a lot of drive

I just formatted a 120G drive and it came back with 111G.

Wow, I can’t believe it. I know drives typically come up less than what they are advertised for, but it has never amounted to very much space. Now that it’s 9G I’m missing out on, I feel like I have to ask: is there any way to reclaim this “lost” space, or is this just the price you have to pay? If nothing else, can anyone explain why this happens?

It’s formatted as NTFS in XP.

A small part of it is space that’s used for OS overhead – actually keeping track of tracks, sectors, etc.

The majority of it, though, has to do with the fact that drives are advertised in “marketing gigabtyes,” which are 1000 megabytes, while operating systems use “real gigabytes”, which are 1024 megabytes. One reason the numbers don’t add up.

the fact that drives are advertised in “marketing gigabtyes”

LOL, thanks Denny. I knew there was a technical reason. The first time this happened to me, I actually called the drive manufacturer and complianed. He essentially told me what you just did, but it sounded much more complicated when he said it.


I had the same thing happen. My new Western Digital 120GB Special Edition hard drive is really only a 111GB drive :( Denny is correct with the “marketing” GBs.


Remember that after formatting a 2MB (“real megabytes”) floppy, you only have 1.44MB left. It’s also good to know that the hard drive gigabytes are 10^9 bytes (the usual “giga” in the computer world is 2^30).

What I meant was that the hard drive probably is 120GB in the usual sense of the prefix “giga”, even after formatting. 120*10^9 / 2^30 = 111.76. Windows will report the computer “giga”.

You beat me to it :)

heh, he should’ve tried formatting it for FAT16 or even FAT32. He’d really be crying, due to the size of the clusters. :D

Tim, read this in order to get an idea of why it is happening. Be sure to also click on the Managing Partitions link on that page too.