How come my new XX GB Hard Drive is not XX GB after being formatted?
The formatted capacity is almost always less than the drive rating (label/packaging). Although some drives may be listed by their formatted capacity – almost every drive is sold by its decimal size rating – not binary which the computer uses (read on). (There’s also some space used by the formatting/partitions/file allocation table, etc. but this is a relatively small amount.) The reasons why a 9GB Drive formats to appx. 8.4GB (or your 80GB drive is reported as appx 74.5GB, etc.) is usually due to the binary vs decimal number scheme, but also remember formatted capacity can vary depending on block size, partition data and spares (spare sectors). This often varies depending on OS and formatting/driver software used. By far the biggest part of the ‘loss’ is the binary vs. decimal number scheme i.e. Binary for 1K (1000) is 1024, decimal is 1000 • 1GB in Decimal (base 10) is 1,000,000,000 • 1GB in Binary (base 2) is 1,073,741,824 Now you can see how with larger drives this would be even mo