How to Convert Audio Files Between MP3, FLAC, AAC, and More

At some point, every music lover needs to convert an audio file. Maybe your car stereo only reads MP3, your audiophile DAC wants FLAC, or you're uploading to a platform that requires a specific format. Whatever the reason, converting audio is straightforward — as long as you understand a few key rules.

The Golden Rule: Lossy to Lossless Doesn't Restore Quality

Before you start converting, understand this: converting a lossy file (MP3, AAC) to a lossless format (FLAC, WAV) does not improve its quality. You'll get a larger file that sounds identical to the original lossy source. The quality damage from lossy compression is permanent. The only exception is when converting from a high-quality lossy source to another lossy format at an equal or higher bitrate — quality loss is minimal in that case.

Always start from the highest quality source available.

The Best Free Audio Conversion Tools

Option 1: foobar2000 (Windows) — Recommended

foobar2000 is not just a player; it's a powerful converter. Here's how to use it:

  1. Download and install foobar2000 from foobar2000.org
  2. Install the free encoder pack (available on the same site) to enable MP3, AAC, and FLAC output
  3. Add your files to the library, then select the ones you want to convert
  4. Right-click → Convert → Quick Convert or Convert → … for custom settings
  5. Choose your output format, set your bitrate (for lossy) or compression level (for FLAC), and hit Convert

foobar2000 handles batch conversion beautifully and preserves metadata (tags) automatically.

Option 2: VLC Media Player (All Platforms)

VLC can convert audio files without any additional installs:

  1. Open VLC and go to Media → Convert/Save
  2. Click Add and select your source files
  3. Click the Convert/Save button
  4. In the Profile dropdown, choose your target format (MP3, FLAC, AAC, etc.)
  5. Set a destination file and click Start

Option 3: FFmpeg (Command Line — All Platforms)

FFmpeg is the most powerful and flexible option, used by professionals and developers. It runs from the command line and can handle virtually any format conversion imaginable.

Example commands:

  • FLAC to MP3 at 320kbps: ffmpeg -i input.flac -b:a 320k output.mp3
  • MP3 to AAC: ffmpeg -i input.mp3 -c:a aac -b:a 256k output.m4a
  • WAV to FLAC: ffmpeg -i input.wav output.flac

FFmpeg is free and open-source. Download it from ffmpeg.org.

Option 4: Online Converters (Quick & Easy)

For one-off conversions without installing software, browser-based tools like CloudConvert or Convertio are convenient. Upload your file, choose an output format, and download the result. Be mindful of file size limits and avoid uploading sensitive or private audio through third-party services.

Recommended Conversion Settings

Conversion Recommended Settings Notes
FLAC → MP3 320 kbps CBR or V0 VBR High quality, universal compatibility
FLAC → AAC 256 kbps Efficient; great for Apple devices
WAV → FLAC Compression Level 5–8 No quality loss; saves space
MP3 → MP3 Match or lower the source bitrate Re-encoding lossy files adds artifacts

Don't Forget Metadata

When converting, always verify that your tags (artist, album, track number, cover art) transferred correctly. Tools like MusicBrainz Picard or Mp3tag can fix missing or garbled metadata after conversion.

With the right tool and a bit of care, audio conversion is a quick and painless process. Start from the best source you have, choose sensible settings, and your converted files will sound great on any device or platform.