Megabits (Mb) and megabytes (MB) sound identical, and their abbreviations use the exact same letters, but they certainly don't mean the same thing.

It's important to be able to distinguish between the two when you're calculating things like the speed of your internet connection and the size of a file or hard drive.

What does it mean if you're testing your internet speed and you're told it's 18.20 Mbps?
How much is that in MB? What about a flash drive that has 200 MB left - can I read it in Mb if I want to?

The Little "b" vs the Big "B"
Megabits are expressed as Mb or Mbit when talking about digital storage, or Mbps (megabits per second) in the context of data transfer rates. All of these are expressed with a lowercase "b."

For example, an internet speed test can measure your network's speed at 18.20 Mbps, which means that 18.20 megabits are being transferred every second. What's interesting is that the same test can say that the available bandwidth is 2.275 MBps, or megabytes per second, and the values are still equal.

If a file you're downloading is 750 MB (megabytes), it's technically also 6000 Mb (megabits).

Here's why, and it's very simple
Young businesswoman using laptop in office
Hero Images/Digital Vision/Getty Images
by Paul Gil
Updated March 22, 2017
Megabits (Mb) and megabytes (MB) sound identical, and their abbreviations use the exact same letters, but they certainly don't mean the same thing.

It's important to be able to distinguish between the two when you're calculating things like the speed of your internet connection and the size of a file or hard drive.

What does it mean if you're testing your internet speed and you're told it's 18.20 Mbps?


How much is that in MB? What about a flash drive that has 200 MB left - can I read it in Mb if I want to?

The Little "b" vs the Big "B"
Megabits are expressed as Mb or Mbit when talking about digital storage, or Mbps (megabits per second) in the context of data transfer rates. All of these are expressed with a lowercase "b."

For example, an internet speed test can measure your network's speed at 18.20 Mbps, which means that 18.20 megabits are being transferred every second. What's interesting is that the same test can say that the available bandwidth is 2.275 MBps, or megabytes per second, and the values are still equal.

If a file you're downloading is 750 MB (megabytes), it's technically also 6000 Mb (megabits).

Here's why, and it's very simple...

There Are 8 Bits in Each Byte
A bit is a binary digit, or small unit of computerized data. A bit is really, really small - smaller than the size of a single character in an email.

For the sake of simplicity, think of a bit as the same size of a text character. A megabit, then, is approximately 1 million typed characters.

Here is where the formula 8 bits = 1 byte can be used to convert megabits to megabytes, and vice versa. Another way to look at it is that a megabyte is 1/8 of a megabit, or that a megabyte is 8 times that of a megabyte.

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