Question 1

What’s the difference between MB and MiB (decimal vs binary)?

Accepted Answer

A megabyte (MB) is a decimal unit equal to 1,000,000 bytes, using powers of 1000. A mebibyte (MiB) is a binary unit equal to 1,048,576 bytes, using powers of 1024. They’re close but not equal: 1 MiB is about 4.9% larger than 1 MB, and the gap widens at higher units (a TiB is about 10% larger than a TB). Storage manufacturers and networks use the decimal units, while operating systems and memory typically count in binary units — which is the root of most “missing space” confusion.

Question 2

Why do drive sizes look smaller than advertised?

Accepted Answer

Drive makers label capacity in decimal units: a “1 TB” disk holds 1,000,000,000,000 bytes. Your operating system, however, often displays capacity in binary units (gibibytes) while still calling them “GB”. Dividing that same byte count by 1024³ gives about 931, so the drive shows as roughly 931 “GB”. No space is missing — it’s purely a difference in how the same number of bytes is counted. Some space is also reserved for formatting and the file system, which reduces usable capacity slightly further.

Question 3

What’s the difference between bits and bytes?

Accepted Answer

A byte is eight bits. Storage is usually measured in bytes (capital B), while data-transfer and network speeds are measured in bits (lower-case b) — which is why a “100 Mbps” connection downloads at around 12.5 megabytes per second, not 100. The factor of eight catches many people out when estimating how long a download will take. This converter works in bytes; to convert a speed in bits to bytes, divide by eight first.

Byte Converter — KB, MB, GB, TB (and KiB/MiB/GiB)

Decimal (SI · 1000-based)

Binary (IEC · 1024-based)

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