Audio compressor
Re-encode an audio file at a lower bitrate to make it much smaller.
How to use
- Choose an audio file (MP3, WAV, M4A, OGG, FLAC, AAC…).
- Pick a bitrate (96 kbps is a good balance) and, if you like, mono.
- Press Compress, listen to the result and download the .m4a file.
Audio compressor
Your browser decodes the file and re-encodes it as AAC (.m4a) with WebCodecs. Lower bitrates make smaller files at the cost of quality: 128–192 kbps is close to the original for most music, 64–96 kbps is fine for speech and podcasts, and 48 kbps suits voice notes. Mono halves the size again for speech.
The output is AAC in an .m4a file (or Opus in an .opus file if your browser cannot encode AAC); there is no MP3 output. If the source is already small the result may not be smaller, and you are told. Audio is never uploaded. Very long files can be slow on phones.
Frequently asked questions
Which formats can I compress?
Whatever your browser can decode: MP3, WAV, M4A/AAC, OGG, FLAC and the audio in MP4 or WebM files.
What bitrate should I choose?
96 kbps is a good default; use 128–192 kbps for music you care about and 48–64 kbps for speech.
Can I get an MP3?
No. The output is AAC (.m4a), which plays on phones, computers and most players. If your browser cannot encode AAC it saves Opus (.opus) instead.
Is my audio uploaded?
No. It is processed in your browser.