How file-size conversion works
Every unit is converted to bits first, then divided by the number of bits in the target unit. The formula is value × source unit in bits ÷ target unit in bits. Because one byte contains eight bits, converting bytes to bits multiplies by eight.
GB and GiB are not the same
SI prefixes use powers of 1,000. One GB is exactly 1,000,000,000 bytes. IEC binary prefixes use powers of 1,024. One GiB is exactly 1,073,741,824 bytes, so 1 GB converts to about 0.9313 GiB.
| Unit | Exact size in bytes | System |
|---|---|---|
| MB | 1,000,000 | SI decimal |
| MiB | 1,048,576 | IEC binary |
| GB | 1,000,000,000 | SI decimal |
| GiB | 1,073,741,824 | IEC binary |
Bits and bytes use different symbols
A lowercase b means bit and an uppercase B means byte. For example, 100 MB equals 800 Mb. The converter keeps those symbols distinct.
Frequently asked questions
Is 1 GB the same as 1 GiB?
No. One GB is 1,000,000,000 bytes, while one GiB is 1,073,741,824 bytes.
How many bits are in a byte?
There are eight bits in one byte.
What is the difference between MB and MiB?
MB is an SI decimal unit equal to 1,000,000 bytes. MiB is an IEC binary unit equal to 1,048,576 bytes.
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