Audio Converter

For sharing or streaming pick AAC/M4A or MP3 at 256 kbps - they sound great on consumer headphones and are widely compatible. For archival of original recordings pick FLAC (lossless, ~50 percent smaller than WAV) or WAV (uncompressed). Avoid converting from one lossy format to another (MP3 to AAC) - go back to a lossless source if you have one, otherwise the second re-encode adds audible artifacts.

Both are lossless - the audio reconstructs to exactly the original samples. WAV stores them uncompressed in a simple container; FLAC compresses them losslessly to roughly half the size. FLAC also supports tags (artist, album, cover art); WAV barely does. Pick FLAC unless you specifically need WAV for a tool that does not understand FLAC.

Possibly. Converting MP3 to MP3 at the same bitrate is roughly a wash. Converting MP3 to AAC may sound cleaner but you have already lost detail in the first MP3 step. Converting MP3 to FLAC or WAV does not improve quality - the lossless format just preserves whatever quality the MP3 had. The general rule: never convert lossy to lossy more than once if you can avoid it.

Yes - drop a video (MP4, WebM, MOV, MKV) and pick an audio format. The video track is automatically dropped and only the audio is re-encoded. This is the same workflow as the dedicated extract-audio-from-video tool, just with a wider format menu.

Because FLAC is lossless. A 5-minute song is ~5 MB at 128 kbps MP3, ~7 MB at 192 kbps MP3, and 25-35 MB at FLAC. The FLAC contains every detail the MP3 had to discard. If you need small files pick MP3 or Opus; if you need perfect fidelity pick FLAC and accept the size.

Roughly real-time or faster. A 5-minute MP3 conversion finishes in about 5-10 seconds plus upload time. WAV and FLAC encoding is slightly slower. The 500 MB file size limit corresponds to roughly a 10-hour stereo audio file at 320 kbps, well above any normal use case.

Files travel over HTTPS to api.zeroutil.com (EU server). FFmpeg processes them locally on the server, returns a signed download URL, and both the input and the converted file are auto-deleted after 15 minutes. We do not log content, do not transcribe audio, and do not retain anything beyond the deletion window.