Bits per second
Bitrate is the amount of data transferred or processed per unit of time. It is commonly measured in bits per second (bit/s), kilobits per second (kbit/s), or megabits per second (Mbit/s).
Network plans usually use decimal SI prefixes. A connection advertised as 100 Mbit/s has a theoretical maximum of 12.5 MB/s before protocol overhead, because eight bits make one byte.
Media quality and compression
For audio and video, a higher bitrate can preserve more detail, but bitrate alone does not determine quality. Codec efficiency, resolution, frame rate, source quality, and encoding settings all matter.
File size can be estimated by multiplying bitrate by duration and then dividing by eight to convert bits to bytes. Variable-bitrate media changes over time, so the result is an estimate based on average bitrate.