MP3 encoding a set filesize?

[Brainiac]

Hi all,
Is there any software or encoding method available that will encode a wav file to an mp3 at a specified filesize? For example, I would input a wav file and set the resultant filesize of the mp3 to 25 mb or less and the software would generate the settings for the mp3 file automatically.

[jagabo]

The definition of bitrate is:

bitrate = size / running time

For mp3 size is expressed in bits and time is expressed in seconds.

Example: for a 3 minute 30 second audio file (210 seconds), to be 5,000,000 bytes (40,000,000 bits):

bitrate = 40,000,000 bits / 210 seconds
bitrate = ~190,476 bits per second
bitrate = ~190 kbps

[Brainiac]

Thank you, jagabo!