Data Storage Converter

What a bit really measures

Digital storage units quantify information, and the smallest atom of that information is the bit — a single yes-or-no, on-or-off, 0-or-1. Eight bits clump into a byte, the practical unit used to encode a character of text, while a nibble (four bits) is the half-byte that hexadecimal notation maps onto neatly. Everything else is just prefixes stacked on top.

From punched cards to petabytes

The byte was popularized in the 1950s and 60s with IBM's System/360, which standardized the 8-bit byte across an entire computing platform. For decades, prefixes like kilo and mega were used loosely: engineers meant 1024 (a tidy power of two), while the rest of the metric world meant 1000.

The International Electrotechnical Commission settled the fight in 1998 by introducing binary prefixes — KiB, MiB, GiB, TiB — for the powers of 1024, leaving kB, MB, GB for clean powers of 1000. Adoption has been famously uneven.

Where the prefixes live now

Drive manufacturers and networking equipment stick to decimal: a 1 TB SSD genuinely contains 10¹² bytes. Operating systems, memory chips, and file sizes lean binary, which is why Windows reports that same drive as roughly 931 GiB. Networking adds another twist by measuring throughput in bits per second — Mbps and Gbps — not bytes.

Where the math goes wrong

A handful of mistakes account for most of the confusion around storage figures.

• Assuming a 1 TB drive is "missing" space — it is not; the OS is just counting in GiB.
• Equating a 1 Gbps internet line with 1 GB/s downloads. Divide by 8: real-world ceiling is about 125 MB/s.
• Mixing Mb (megabit) and MB (megabyte) in the same sentence — they differ by a factor of eight.
• Treating RAM and disk capacity with the same prefix convention; memory modules are virtually always binary.