Decimal and binary units

Decimal storage units use powers of 1,000: one kilobyte is 1,000 bytes and one gigabyte is 1,000,000,000 bytes. Binary IEC units use powers of 1,024: one kibibyte is 1,024 bytes and one gibibyte is 1,073,741,824 bytes.

Why displayed capacity differs

Storage manufacturers commonly state capacity in decimal units, while some operating systems display binary quantities using decimal-looking labels. A device sold as 1 TB contains one trillion bytes, equal to about 931.323 GiB before formatting and system use.

Bits are not bytes

A lowercase b normally means bit, while uppercase B means byte. Eight bits make one byte. Network speeds stated in megabits per second are therefore not directly equal to file sizes in megabytes.

This tool converts byte-based quantities. Available device capacity can be lower because of formatting, reserved areas, redundancy, and system files.