HD File Space/Capacity Question

Hi

I bought a Macbook 13" that comes with 120GB.

It arrived yesterday and when I click on Macintosh HD on the desktop it says on the bar below "94GB available" - or approximately that number.

Why does it not say 120GB?

Because it has OS X and other applications pre-installed that take up some of the space. Also the drive probably isnt 120gb.120gb is just an approximate, so it was probably more like 115gb to start with.

"Mac OS X reports hard drive capacity in binary math, hard drive manufacturers report capacity in base 10 math"

"Modern operating systems such as Mac OS X use binary mathematics to define the total capacity of a hard drive. Using binary math, an 80-gigabyte (GB) hard drive reports approximately 74.51 GB of available space.

In binary math, 1 GB is equal to 1,073,741,824 bytes, whereas conventional (or base 10) mathematics instead calculate 1 GB as exactly 1,000,000,000 bytes.

This numerical discrepancy (73,741,824 bytes per gigabyte) represents a difference between the physical “base 10” specification used by hard drive manufacturers and Mac OS X’s binary measurement of available capacity. The 80 GB and 74.51 GB values represent two methods of mathematical measurement that describe a hard drive with approximately 80 billion bytes.

This is normal behavior, and there is no hard disk space missing. Regardless of which method is used to measure total capacity, the storage capacity in bytes of the hard drive is the same. Previous operating systems (including Mac OS 9 and earlier versions) also demonstrate this mathematical difference.

Other factors, such as the system software, applications, updates, and your files and data use part of the available disk capacity, meaning a new Macintosh computer will not show the total capacity listed as available for use. The amount of hard disk drive space required for normal operation of a Macintosh computer will vary widely, depending on configuration, model, and personal requirements.

Note: Hard disk manufacturers may also round off decimal places when stating storage specifications, such as approximately "39.5 GB" instead of "39.49 GB". "

http://docs.info.apple.com/article.html?artnum=30065

plus anytime after "formatting" a harddrive there is always going to be less than allotted, then throw in all the preloaded software.