Locate the file on your hard drive. If you have it within a media player, you will need to find the original file on either your Macintosh or Windows computer.
Select the file by clicking on the icon. When the icon appears highlighted you will know you have selected it correctly.
Find the bit rate information by right-clicking on the file and selecting "Get Info" on a Macintosh. The total bit rate will be listed under the "More Info" tab in the information screen that pops up. In Windows, select the properties menu. This will give you a list of information, including the bit rate.