Convert between bits, bytes, kilobytes, megabytes, gigabytes, terabytes, petabytes and more.
Digital storage and data transfer are measured using units based on binary (base-2) mathematics. A bit is the smallest unit of digital data — a single 0 or 1, representing the two states of a transistor. Eight bits make one byte, which can represent 256 different values (2⁸). All files, messages, photos, videos, and programs are ultimately sequences of bits stored in memory or on disk.
A persistent source of confusion is the difference between decimal and binary prefixes. Hard drive manufacturers use decimal: 1 TB = 1,000,000,000,000 bytes. Operating systems use binary: 1 TiB (tebibyte) = 2⁴⁰ bytes = 1,099,511,627,776 bytes. This discrepancy is why a "1 TB" drive shows as about 931 GB in Windows or macOS — the OS uses binary measurement while reporting the label from the decimal-defined drive. The IEC introduced official binary prefixes (kibibyte, mebibyte, gibibyte, tebibyte) in 1998 to resolve this, but consumer products rarely use them.
Internet connection speeds are measured in bits per second, not bytes — and this is not an accident. Dividing by 8 converts from bits to bytes. A "100 Mbps" broadband connection downloads at a maximum of 12.5 megabytes per second (MB/s). This distinction between megabits (Mb) and megabytes (MB) is important when comparing advertised speeds to actual file download times.
Data storage conversions matter when comparing cloud storage plans, understanding why a drive shows less space than advertised, calculating how many photos or videos fit on a memory card, estimating file transfer times, planning server storage for backup systems, or understanding the difference between download speed (bits) and file size (bytes).
In computing, 1 gigabyte equals 1,024 megabytes (using binary prefixes). However, storage manufacturers often use 1 GB = 1,000 MB (decimal). This tool uses binary (1 GB = 1,024 MB).
1 kilobyte equals 1,024 bytes in the binary system used by computers. In the decimal system, 1 kilobyte = 1,000 bytes. Most operating systems display file sizes using binary kilobytes.
GB (gigabyte) in marketing context often means 1,000,000,000 bytes (decimal). GiB (gibibyte) is the precise binary term for 1,073,741,824 bytes (2^30). Operating systems typically report storage in GiB but label it GB.
There are exactly 8 bits in one byte. This is a fundamental definition in computing. A single bit is the smallest unit of data (0 or 1), and a byte can represent 256 different values.
One petabyte equals 1,024 terabytes, 1,048,576 gigabytes, or approximately 1.13 billion gigabytes. To put it in perspective, 1 petabyte could store about 11 years of continuously recorded HD video.