Taken from Seagate's FAQ's about their drives ... Western Digital say the same thing ...
Quote ... "Hard drive manufacturers market drives in terms of decimal (base 10) capacity. In decimal notation, one megabyte (MB) is equal to 1,000,000 bytes, and one Gigabyte (GB) is equal to 1,000,000,000 bytes.
Much of this information is available from the National Institute of Standards and Technology at
http://physics.nist.gov/cuu/Units/binary.htmlPrograms such as FDISK, system BIOS, and Windows use the binary (base 2) numbering system. In the binary numbering system, one megabyte is equal to 1,048,576 bytes, and one gigabyte is equal to 1,073,741,824 bytes.
Simply put, decimal and binary translates to the same amount of storage capacity. Let's say you wanted to measure the distance from point A to point B. The distance from A to B is one kilometer or .621 miles. It is the same distance, but it is reported differently due to the measurement.
Capacity Calculation Formula
Decimal capacity / 1,048,576 = Binary MB capacity
Example:
A 40 GB hard drive is approximately 40,000,000,000 bytes (40 x 1,000,000,000).
40,000,000,000 / 1,048,576 = 38,162 megabytes" ... unquote
In other words, formatted capacity and actual capacity are two different things. They just round the figures up to make it look good in the adverts. :-D
