Kbps is primarily used to measure data transfer rates. For example, dial-up modems were rated by their maximum download speeds, such as 14.4, 28.8, and 56 Kbps. Throughout the 1990s and early 2000s, Kbps remained the standard way to measure data transfer dates. However, broadband connections such as cable and DSL now offer speeds of several megabits per second. Therefore, Mbps is more ubiquitous than Kbps.
NOTE: The lowercase "b" in Kbps is significant. It stands for "bits," not bytes (which is represented by a capital "B"). Since there are eight bits in one byte, 400 Kbps is equal to 400 ÷ 8, or 50 KBps. Because data transfer speeds have traditionally been measured in bps, Kbps is more commonly used than KBps.
Updated: October 8, 2016