💾 Data Storage Converter
Enter a value and pick its unit. Results are shown both ways: the binary definition disk and memory manufacturers vs. operating systems disagree on (1 KB = 1024 bytes) and the decimal SI definition (1 KB = 1000 bytes) used on some spec sheets.
Two definitions, one prefix
The Definition dropdown picks the base every step of the ladder uses, and bits are always an eighth of a byte:
bytes = value × base ^ steps base = 1024 or 1000
bits = bytes × 8
1 GB (binary) = 1024³ = 1,073,741,824 bytes
1 GB (decimal) = 1000³ = 1,000,000,000 bytesDrive and flash manufacturers sell in decimal; Windows reports in binary while still writing "GB". Nothing is missing from the disk - the two sides are counting with different sized units.
How far the two drift apart
| Unit | Binary bytes | Decimal bytes | Binary is bigger by |
|---|---|---|---|
| KB | 1,024 | 1,000 | 2.4% |
| MB | 1,048,576 | 1,000,000 | 4.9% |
| GB | 1,073,741,824 | 1,000,000,000 | 7.4% |
| TB | 1,099,511,627,776 | 1,000,000,000,000 | 10.0% |
| PB | 1,125,899,906,842,624 | 1,000,000,000,000,000 | 12.6% |
The gap compounds by roughly 2.4% per step, so it is invisible on a photo and obvious on a hard disk.
Frequently asked questions
How many MB are in a GB?
1024 MB under the binary definition, which is what your operating system shows, or 1000 MB under the decimal one used on packaging. Pick the matching definition above and the tool answers either way.
Why does my 1 TB drive show only 931 GB?
The maker counted 1,000,000,000,000 decimal bytes; the computer divides that by 1024 three times and reports 931.32 GB. Both numbers describe the same drive, and no space has been lost to formatting.
Is 100 Mbps the same as 100 MB per second?
No, and the difference is a factor of eight. Mbps counts megabits, so 100 Mbps is 12.5 MB per second at best. Convert with the Bits row here and use the decimal definition, which is what network speeds are quoted in.