Bandwidth

Bandwidth is how fast information can be moved from one computer to another, or more generally, from one device to another. A device with a high bandwidth will transfer data more quickly, which means you can more quickly download files and browse the Web with it.

All of the information on your computer is stored as a series of 1’s and 0’s. Each 1 or 0 is called a "bit," and eight bits strung together are called a “byte.” Bandwidth is usually expressed in bits per second (bps or bit/s), but it is also sometimes expressed in bytes per second (Bps). So if a device has a bandwidth of 5 bps, that means it can send 5 bits of data (5 1's or 0's) in a second.

Bandwidth can also be expressed in Kbps or Kbit/s (kilobits per second) for one thousand bits per second, Mbps or Mbit/s (megabits per second) for one million bits per second, or Gbps or Gbit/s (gigabits per second) for one billion bits per second. Sometimes bandwidth is just written as K, which means kilobits per second, not kilobytes per second.

You will see bandwidth listed for dial-up modems, the fastest of which transfer data at 56 Kbps; standard wireless networking devices, which transfer data close to 200 times faster at 11 Mbps; and digital subscriber line (DSL) technology, which typically transfers data between 128 Kbps and 24 Mbps. The bandwidth you see listed for a device is the maximum speed at which it can transfer data. The actual speed of data transfer will depend on various network conditions and is typically slower than the maximum.