What is Bitrate?
Also called: kbps, bit rate
Bitrate is the amount of data used per second of audio, usually given in kilobits per second (kbps). Higher bitrates generally mean better quality and larger files for lossy formats like MP3 and AAC.
For uncompressed audio, the bitrate follows directly from the format: sample rate times bit depth times channels. CD quality stereo (44.1 kHz, 16 bit) works out to about 1,411 kbps.
Lossy formats choose a much lower bitrate and throw away the details the encoder judges least audible. MP3 goes up to 320 kbps. Constant bitrate (CBR) keeps the same rate throughout, while variable bitrate (VBR) spends more data on complex passages and less on simple ones.
Raising the bitrate of a file that was already compressed does not bring back what was lost; it only makes the file bigger. Always encode from the best quality source you have.
Example
A 3 minute MP3 at 320 kbps is about 7.2 MB, while the same length as a 44.1 kHz, 16 bit stereo WAV is about 31.8 MB.
Put it to work
Calculate file size from bitrate and length, or the bitrate from a file's size.
Audio File Size and Bitrate Calculator