External drive reporting wrong capacity

Hi All,

We use a 1tb Western Digital USB3 external drive for a system backup on a desktop PC under windows 10. After formatting it's showing 931gb capacity.

The Windows Image Backup file is approx 560gb. Problem is the drive is now saying there is only 79gb space available on the drive. I ticked the "show hidden files" option but there still only seems to be a total of 560gb on the drive.

Any idea what's happened to the remaining disk space or how we can get it back? Just spent the last hour on Google trying to find a solution but don't seem to be getting anywhere

Thanks in advance if anyone can help...

No. It is just way windows reports a kilobyte as 1024 bytes but strictly a kilobyte is 1000 bytes.

Thus 931 GB is 931*1024*1024*1023 bytes equals 1000,000,000,000 bytes.

Drive manufacturers use strict 1000 bytes to kilobyte definition.

It is actually Windows that is wrong really but been that for ever. If you used same drive on OSX, same capacity would be reported as 1000 GB

Berton said:

My MacBook Pro with a 500GB HDD is showing as 498.88GB using Mac OS Extended (Journaled) formatting. It also could be called HFS Plus. The formatting of HDDs using FAT/FAT16/FAT32, exFAT or NTFS will report different capacities.

Windows and the older DOS basically use multiples of 2 when working with RAM/Random Access Memory and drive storage such as 2, 4, 8, 16, 32, 128, 256, 1024, etc.

Apple use strict definition of kilo as 1000.

Windows do not. The term KiB has now been introduced to mean 1024 (GiB is 1024*1024*1024 whereas as GB is 1000*1000*1000).

So Windows actually reports GiB but calls them GB (of course windows predates GiB).

so 931 GiB = 1000 GB.