MBps is an abbreviation for Megabytes per second, whereas Mbps is an abbreviation for megabits per second. Eight megabits equal one Megabyte. These abbreviations are commonly used to specify how much data can be transferred per second between two points. In some cases, mbps is used as an abbreviation for megabits per second; however, the lowercase m technically means "milli" not "mega," so it doesn't really mean the same thing.
To put megabits and Megabytes in perspective, let's back up for just a moment. One bit of data is a single "on" or "off" digit, a one or zero. It takes eight bits to represent a single character, or one byte of data.
- 8 bits = 1 byte
- 1000 bytes = 8 kilobits (kb) = 1 Kilobyte (KB)
- 1000 Kilobytes (KB) = 8 megabits (Mb) = 1 Megabyte (MB)
As a point of possible confusion it should be mentioned that there are two different systems for calculating multiples of data: the decimal system as noted above, and the binary system.
According to the binary system, used in relation to computer storage and memory, it takes not 1000 bytes to equal a KB, but 1024 bytes. This is because the binary system is base 2, and 210 = 1024. Technically, the designations in this case are Kibibyte (KiB) and Mebibyte (MiB), but these haven't caught on in the public sector, leading many uses of "MB" to mean 1024 kilobytes, and others to mean 1000 kilobytes. When considering MBps, however, the decimal system applies, as the reference is to data transfer rates and not data storage.
Data transfer rates are quite handy for gauging performance levels of various hardware devices. Everything from USB and Firewire® ports to memory card readers and mobile devices are associated with corresponding transfer rates, often measured in megabits or Megabytes per second.
We must also translate speed to value when considering Internet service plans, advertised by download and upload speeds expressed in kilobits per second (kbps) or megabits per second. For example, a typical Digital Subscriber Line (DSL) plan might have an upper transfer limit of 1,500 kbps, which can also be expressed as 1.5 Mbps. A cable plan might be advertised with speeds up to 5,000 kbps or 5 Mbps; and fiber optic Internet can reach speeds of 50 Mbps or more.
The wireless G network (802.11g) has a maximum transfer rate of 54 Mbps, making it much faster than all but the fastest fiber optic Internet plans. Thankfully, going wireless won’t slow your surfing. The more current wireless N standard (802.11n) can’t speed up your Internet connection, but will allow faster data transfer rates between local networked computers of up to 100 Mbps, or about twice the data transfer rate of G networks.
As if the abbreviations aren't close enough to cause confusion, it doesn’t help that they are often expressed in the wrong case. When in doubt look for translations such as the kilobit or Kilobyte equivalent, or simply ask someone if the specification is indeed megabits per second or Megabytes per second.