File size measures the size of a computer file. Typically it is measured in bytes with a prefix. The actual amount of disk space consumed by the file depends on the file system.
The maximum file size a file system supports depends on the number of bits reserved to store size information and the total size of the file system. For example, with FAT32, the size of one file cannot be equal or larger than 4 GiB.
Some common file size units are:
| Name | Symbol | Binary Measurement | Decimal Measurement | Number of Bytes | Equal to |
|---|---|---|---|---|---|
| KiloByte | KB | 210 | 103 | 1,024 | 1,024 bytes |
| MegaByte | MB | 220 | 106 | 1,048,576 | 1,024 KB |
| GigaByte | GB | 230 | 109 | 1,073,741,824 | 1,024 MB |
| TeraByte | TB | 240 | 1012 | 1,099,511,627,776 | 1,024 GB |
| PetaByte | PB | 250 | 1015 | 1,125,899,906,842,624 | 1,024 TB |
| ExaByte | EB | 260 | 1018 | 1,152,921,504,606,846,976 | 1,024 PB |
| ZettaByte | ZB | 270 | 1021 | 1,180,591,620,717,411,303,424 | 1,024 EB |
| YottaByte | YB | 280 | 1024 | 1,208,925,819,614,629,174,706,176 | 1,024 ZB |