What is mebibyte (binary)?

A mebibyte is a binary data unit equal to 1,024 kibibytes, or 1,048,576 bytes. It is used in operating systems, RAM specifications, and software contexts where exact binary data sizes are required.

Real-world uses

Mebibytes are used by operating systems when reporting RAM size and filesystem usage. Windows Task Manager and Linux tools such as "free" and "df" report memory in MiB. RAM sticks are specified in binary multiples; a "4 GB" RAM module is actually 4 GiB = 4,096 MiB.

History

The mebibyte was standardised by the IEC in 1998 alongside the kibibyte and gibibyte to eliminate the ambiguity created by the historical use of "megabyte" to mean either 1,000,000 or 1,048,576 bytes. Adoption has been gradual, with the Linux kernel and many technical tools now using MiB correctly.

Common mistakes

Confusing MiB (mebibyte, 1,048,576 bytes) with MB (megabyte, 1,000,000 bytes). A mebibyte is approximately 4.86% larger than a megabyte. Software that reports in MiB may appear to show less space than marketing specifications that use MB.

What is kibibyte (binary)?

A kibibyte is a binary data unit equal to 1,024 bytes. It is the IEC-standard unit that precisely distinguishes binary-based kilobyte measurements from the decimal kilobyte used in storage marketing.

Real-world uses

Kibibytes are used in operating system kernels, Linux system tools, and technical documentation where binary precision matters. Memory allocations, filesystem block sizes, and network buffer sizes are specified in kibibytes to avoid decimal ambiguity. The Linux kernel, GNU tools, and JEDEC standards all use binary prefixes.

History

The kibibyte was defined by the International Electrotechnical Commission (IEC) in 1998 as part of IEC 80000-13 to resolve the longstanding ambiguity between decimal and binary multiples of bytes. The prefix "kibi-" derives from "kilo binary" (2^10 = 1,024).

Common mistakes

Confusing KiB (kibibyte, 1,024 bytes) with kB (kilobyte, 1,000 bytes). The difference is 2.4%, small but significant at scale. Many users and some software still use "kB" to mean 1,024 bytes despite the IEC 1998 standardisation of "KiB".

When is this conversion used?

Operating systems and storage manufacturers use different base systems (binary vs decimal), which is why a '1 TB' drive shows less than 1 TB in your file manager. Understanding this conversion prevents confusion about available storage.

Worked examples

1 mebibyte (binary) = 1,024 kibibyte (binary)

1 kibibyte (binary) = 1,024 byte

How to convert mebibyte (binary) to kibibyte (binary)

To convert mebibyte (binary) to kibibyte (binary), multiply the value by 1,024.

To convert kibibyte (binary) back to mebibyte (binary), multiply by 0.00097656.

Measurement standards

The International Electrotechnical Commission (IEC 80000-13) defines binary prefixes: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes. The SI decimal prefixes (kB = 1,000 bytes, MB = 1,000,000 bytes) apply to data units as they do to all SI quantities.

Did you know?

By 2025, the global datasphere is estimated to reach 181 zettabytes — roughly 181 trillion gigabytes. If stored on standard Blu-ray discs, the stack would reach from Earth to Mars and back over 20 times.

Quick reference: mebibyte (binary) to kibibyte (binary)

mebibyte (binary)kibibyte (binary)
0.1102.4
0.5512
11,024
22,048
55,120
1010,240
2525,600
5051,200
100102,400
250256,000
500512,000
1,0001,024,000

Common values

mebibyte (binary)kibibyte (binary)
A text email0.00476837 mebibyte (binary)4.8828125 kibibyte (binary)
An MP3 song (4 min)3.81469727 mebibyte (binary)3,906.25 kibibyte (binary)
A smartphone photo4.76837158 mebibyte (binary)4,882.8125 kibibyte (binary)
An HD movie4,768.37158203 mebibyte (binary)4,882,812.5 kibibyte (binary)
A full hard drive953,674.31640625 mebibyte (binary)976,562,500 kibibyte (binary)