Data storage: MB, GB, TB, MiB and GiB explained
A drive sold as 1 TB may appear as roughly 931 GiB on a computer. This usually does not mean capacity is missing. The manufacturer and software may simply use different unit systems.
Decimal units
Decimal kB, MB, GB, and TB increase in steps of 1,000. One GB is 1,000,000,000 bytes and one TB is 1,000,000,000,000 bytes. Drive packaging and many cloud services use these definitions.
Binary units
KiB, MiB, GiB, and TiB increase in steps of 1,024. One GiB is 1,073,741,824 bytes and one TiB is 1,099,511,627,776 bytes.
A GiB is larger than a GB, so the same bytes produce a smaller number of GiB. A marketed 1 TB drive is approximately 0.909 TiB or 931.3 GiB.
Ambiguous labels
Some operating systems and programs have historically displayed “GB” while calculating in binary units. When precision matters, inspect both the label and the underlying byte count rather than relying on the abbreviation alone.
Bits and bytes
One byte is exactly 8 bits. Uppercase B means byte and lowercase b means bit. A 100 Mbit/s internet connection therefore has a theoretical maximum of 12.5 MB/s before protocol overhead, wireless conditions, and other losses.
Capacity versus free space
Formatting, file systems, recovery partitions, and installed software use storage. A difference in free space can therefore combine unit conversion with data already occupying the drive.
Cloud plans and backups
Check how a provider defines GB, whether file history counts towards the quota, and whether compression changes the stored size. The converter compares data quantities; it cannot determine a service’s billing rules.
When two systems appear to disagree, compare their byte counts. Bytes are the shared base and remove the decimal-versus-binary ambiguity.