When simply running in the background, Skype uses between 0 and 4 kilobits per second of data throughput over an Internet connection. When making a call, usage rates rise to between 24 and 128 kilobits per second.
Video transmission over Skype requires a higher throughput than text messaging or voice calls. For a single video connection, 128 kilobits per second is the minimum data throughput required, with high-quality calls requiring at least 400 kilobits per second. High-definition video calls require a connection of 1.2 megabits per second.
Group calls also require greater data throughput, with standard-quality calls between three people needing at least 512 kilobits per second. Generally a higher data rate means a higher quality connection.