.flac (Free Lossless Audio Codec) is a lossless audio compression codec. It’s a great format to backup your CDs without loosing any quality. A lot of PC audio players can play .flac files directly, but some portable MP3 players and smartphones often refuse to play .flac natively. In this case you may need to convert your audio files into a more popular format such as MP3.

There are many paid utilities which can do this kind of conversion, but you can do the same job for free.

• Download and install foobar2000 audio player.
  For latest version and more info check foobar2000 website.
• Download lame.exe file and save it somewhere on your computer.
  This is version 3.99 release 5. For latest versions check here. You only need lame.exe file.
• Run foobar2000 and open all .flac audio files you wich to convert.
• Select all files > Right Click > Convert
  
  • Output Format – Select MP3 (LAME). Default bitrate (quality) is 190kbps which is fine for portable players. If you click on Edit you can increase bitrate up to 320kbps.
  • Destination – Choose where to save and how to name you converted files.
  • Click Convert
  • Foobar2000 will ask you to locate lame.exe file. Browse to a location where you previously saved the file and click Open. This only needs to be done once (as long as you don’t delete or move the file).
• Wait for conversion to complete.

Remember, MP3 is lossy data compression format which will somewhat reduce audio quality. At high bitrates such as 320kbps most people would not be able to tell the difference between MP3 version and the original, but I would always recommend to keep your lossless .flac files as well.