And how does it differ from a megabyte (MB)?
A megabit is a unit of measurement for data size, most often used in discussions of data transfer.
All of these abbreviations are expressed with a lowercase ‘b.’

Lifewire / Alex Dos Diaz
Megabits and Megabytes
It takes eight megabits to make a megabyte (abbreviated as MB).
As another example, if a file you’re downloading is 750 MB, it’s also 6,000 Mb.
Bits and Bytes
A bit is a binary digit or small unit of computerized data.
A megabit, then, is approximately the size of one million characters.
The formula8 bits = 1 bytecan be used to convert megabits to megabytes and vice-versa.
Just enter something like “1000 megabits to megabytes” into the search bar.
That’s typically the only time you see megabits mentioned.
At a quick glance, they may seem identical and you might just pick whichever one is cheapest.
That’s why it’s important to recognize this difference.
What About Gigabytes and Terabytes?
A megabyte, for example, is just 1/1,000 a gigabyte, tiny in comparison!
FAQ
One megabit equals 125 kilobytes.
There are 1,000 megabits in a gigabit.
There are 1,000 kilobytes in a megabyte.
A gigabyte is bigger than a megabyte.
One gigabyte contains 1,000 megabytes.