How much data can be transmitted in a time period over a communications channel, often expressed in kilobits per second (kbps).
The difference between bandwidth and data transfer causes much confusion and is worth noting.
Bandwidth is a rate and data transfer is a total. For example, you might be a web hosting plan with 128 kbps of bandwidth for a maximum monthly data transfer of roughly 40 GB.
|128 kbps||= bits||= bytes|
|divide by one billion
Note: many hosts use the terms bandwidth and data transfer interchangeably, referring to the monthly data allowance as bandwidth.
WebHosting Bandwidth – An Introduction
SitePoint.com (May 14, 2001)