File Size Converter

This tool converts file sizes between bytes and their larger units, in both the decimal and binary conventions that cause so much confusion. Digital storage is measured in bytes, but real files are large, so we use prefixes like kilo, mega and giga. The catch is that there are two competing systems. The decimal convention, used by storage manufacturers and most operating systems' display, treats a kilobyte as 1,000 bytes, a megabyte as a million, and so on in powers of a thousand. The binary convention, closer to how computers actually address memory, treats a kibibyte as 1,024 bytes, a mebibyte as 1,024 squared, and so on in powers of 1,024, and uses the distinct names KiB, MiB and GiB. This is why a drive sold as 1 terabyte shows up as about 931 of the binary gigabytes your computer reports, a perennial source of head-scratching. This converter clears it up. You enter a size and choose its unit, and the calculator shows the equivalent in bytes, and in all the decimal units (KB, MB, GB) and binary units (KiB, MiB, GiB) at once. The results update as you type. Use it to convert file and storage sizes, to reconcile the decimal and binary figures, or to understand why a disk's capacity looks different in different places. The decimal units step in factors of 1,000, while the binary units step in factors of 1,024, so the same number of bytes gives a smaller figure in binary units. Knowing which convention a tool uses explains most storage-size discrepancies. Whether you are sizing a download, estimating storage, or just curious why the numbers never quite match, this converter shows every equivalent at once so you can read the size in whichever units you need.

Decimal: 1 KB = 1,000 bytes. Binary: 1 KiB = 1,024 bytes. Storage makers use decimal; computers often display binary, which is why a 1 TB drive shows as ~931 GiB.