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What is the difference between bits and bytes?

Answer: Bits and Bytes both measure amounts of data. However, they are typically used in two different contexts.

Bits, kilobits (Kbps), and megabits (Mbps) are most often used to measure data transfer speeds. This may refer to how fast you are downloading a file, or how fast your Internet connection is. For example, if you are downloading a file on cable modem, your download speed might be 240Kbps. This is much faster than a dial-up modem, which maxes out at 56Kbps.

Bytes, on the other hand, are used to measure data storage. For example, a CD holds 700MB (megabytes) of data and a hard drive may hold 250GB (gigabytes). The other important difference is that bytes contain eight bits of data. Therefore, a 240Kbps download is only transferring 30KB of data per second. However, kilobytes per second is not as commonly used as kilobits per second for measuring data transfer speeds. After all, using kilobits per second (Kbps) makes your connection sound eight times faster!

It is important to know that bytes are abbreviated with a capital B, where as bits use a lowercase b. Therefore, Mbps is megabits per second, and MBps is megabytes per second. So 8Mbps is equal to 1MBps.

Published: November 28, 2005 — by Per Christensson

Answer from the PC Help Center