What is the difference between Megabit (Mbit) and MegaByte (MByte)?

In order to explain this let's go down to the difference of a bit to a byte. A bit (short for ‘binary digit’) is the smallest unit of digital information; simply a 1 or a 0. A byte is a group of eight bits.

Scaling these up, 1 Megabit (MBit / Mb) is 1000,000 bits, and 1 MegaByte (MByte / MB) is 1000,000 bytes, and, as there are 8 bits in every byte, there are 8 Megabits in every MegaByte.

So, in short, 1 Megabit is 1 million ‘1’s and ‘0’s, while 1 MegaByte is 8 million ‘1’s and ‘0’s.

Confusingly both terms are commonly used in computing; MegaBits are most often used for measuring an Internet connection download or upload speeds, while Megabytes are used to measure file size.

In terms of download and upload speeds, when someone says a connection is “30 Megabits per second” this needs to be divided by eight to find the “MegaBytes per second” that will be transferred. The most common way people are confused is when speeds (eg 30 Megabits/Megabytes per second) are written in short forms like 30Mbps or 30MBps without additional clarification as to whether the ‘b’ is representing a bit or a byte, compared to the much clearer ‘30MBit/s’ or ‘30MByte/s’. The common convention for the shortened form, is that a lowercase ‘b’ represents bits, while a uppercase ‘B’ represents bytes.