abbreviation

MB

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MB (abbreviation) means Megabyte: a unit of digital storage equal to one million bytes, or 1,048,576 bytes when counted in binary. Used for file sizes, memory and data allowances. Example: “The photo is about 4 MB, so it should attach fine.”

abbreviation

Megabyte: a unit of digital storage equal to one million bytes, or 1,048,576 bytes when counted in binary. Used for file sizes, memory and data allowances.

"The photo is about 4 MB, so it should attach fine."

"My phone plan includes 500 MB of roaming data."

Megabit, when written with a lower-case b as Mb. One megabit is one eighth of a megabyte and is used mainly for connection speeds.

"The line syncs at 80 Mb per second."

slang My bad: a short written apology admitting a small mistake.

"Sent it to the wrong thread, mb."

How to use MB

Learner’s notes

In plain EnglishA unit for measuring file size, or in chat, a quick way of saying "my bad".

When to use it

The storage sense is neutral and technical; the "my bad" sense is slang and belongs only in casual messages.

Memory tip

Leave a space between the number and the unit and keep the B capital for bytes: 250 MB, not 250mb.

Trace the full origin ↓

Easily confused with

Mb → GB KB mbps

Common pairings

MB of storage file size in MB MB per second

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C2 · Advanced serendipity Fortunate discoveries made entirely by accident.

Gen Z slang rizz Charm — the ability to attract a romantic interest.

B2 · Intermediate empathy The capacity to share another person’s feelings.

C1 · Advanced nonchalant Casually calm and relaxed; unconcerned.

Internet slang delulu Delusional — believing something against the odds.

Etymology nostalgia Greek nostos “return home” + algos “pain”.

C2 · Advanced serendipity Fortunate discoveries made entirely by accident.

Gen Z slang rizz Charm — the ability to attract a romantic interest.

B2 · Intermediate empathy The capacity to share another person’s feelings.

C1 · Advanced nonchalant Casually calm and relaxed; unconcerned.

Internet slang delulu Delusional — believing something against the odds.

Etymology nostalgia Greek nostos “return home” + algos “pain”.

Test yourself on “MB” A quick quiz — meaning, synonyms & usage →

Fill the gap

Can you complete this real example?

The photo is about 4 _____, so it should attach fine.

Etymology

An initialism of megabyte, from the prefix mega- (Greek megas 'great') plus byte.

Origin: English

Synonyms

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megabyte megabit my bad sorry my fault

Related words

sorry Ms oops dismal distressing megabit megabyte my bad

Frequently asked questions

What is the difference between MB and Mb?

Capital B means bytes and lower-case b means bits, and there are eight bits in a byte. So 100 Mb per second of broadband delivers roughly 12.5 MB of files per second.

How many MB are in a GB?

1,024 MB in a gigabyte when counted in binary, or 1,000 MB under the decimal system that storage manufacturers and network operators use. That difference is why a drive sold as 500 GB shows up as slightly less on your computer.

What does mb mean in a text message?

In casual messaging, lower-case "mb" is usually short for "my bad", a quick way of admitting a small mistake. Context makes it clear, since nobody apologises in megabytes.

What is the meaning of MB?

"MB" (abbreviation) means megabyte: a unit of digital storage equal to one million bytes, or 1,048,576 bytes when counted in binary. Used for file sizes, memory and data allowances.

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sorry Ms oops dismal distressing megabit megabyte my bad