Updated June 2026 · runs 100% in your browser
MP3 Compressor
Make MP3 files smaller by lowering the bitrate on your device. No upload, no sign-up, no limits.
Drop MP3 files here
or click to choose
🔒 Processed on your device · 0 bytes uploaded
First file loads the converter engine (~25 MB) — cached after that.
How it works
ConvertCabin loads a local copy of FFmpeg in this browser tab and converts on your device — nothing is uploaded. The first file downloads the engine (~25 MB), then it's cached.
It stays free, unlimited and private, and works offline once loaded.
About MP3 Compressor
Choose a bitrate — lower means a smaller file. 128 kbps is a good balance; 64 kbps is tiny.
Frequently asked questions
How do I use MP3 Compressor?
Drop MP3s, pick a bitrate, and download the smaller files.
Which bitrate should I use?
128 kbps suits most music; 64–96 kbps is fine for speech and gives the smallest files.
Is my file uploaded?
No. It is converted on your device by a local copy of FFmpeg and never uploaded.
What is an MP3 file?
MP3 is the most widely supported audio format. Its lossy compression shrinks audio to a fraction of the original size while keeping it perfectly listenable, which is why it became the standard for music.