MP3 Compressor

Practical focus

Use this page when your source is already MP3 and you want a smaller copy without guessing from a generic preset.

Quick tips

• 320 kbps MP3s often have room to shrink to 192 or 128 kbps.
• Voice MP3s can usually go lower than music.
• Avoid compressing the same MP3 repeatedly.

How to use

• Check the original MP3 if you know its bitrate. A 320 kbps music file can often be tested at 192 kbps or 128 kbps.
• For podcasts, courses, and spoken recordings, try 96 kbps first; for simple voice notes, 64 kbps mono can be enough.
• Do not re-compress the same MP3 again and again. Each lossy-to-lossy pass can remove more detail.
• After compression, listen to a busy part of the file, not only the first few seconds, especially for music.

Recommended settings

Supported formats

Upload MP3 sources directly, or use this page for audio you plan to export as MP3 for broad compatibility.

MP3 output is a safe choice for email, websites, older players, and messaging apps.

Quality vs file size

MP3 to MP3 compression is lossy-to-lossy recompression. The file can get smaller, but it is not a clean restoration or lossless reduction.

Dropping from 320 kbps to 128 kbps can save a lot of space. Dropping an already-small 96 kbps MP3 to 64 kbps saves less and can make artifacts obvious.

Do not use 64 kbps voice settings for music unless size matters far more than sound quality.

Privacy and local processing

Compression runs in your browser, so the original audio is not uploaded to a server.

Large files can still be slow because decoding and encoding use your device memory and CPU.

Things to watch

• Repeated MP3 recompression can compound artifacts.
• If the source MP3 is already low bitrate, there may be little useful size reduction left.