MP3 Compressor
Reduce an MP3's file size by re-encoding at a lower bitrate. Private, in-browser.
🔒 Audio is decoded and edited on your device — recordings never leave your browser.
Make an existing MP3 smaller for email, course uploads or limited storage by re-encoding it at a lower bitrate — locally, with no upload.
About MP3 Compressor
Compress an MP3 in your browser. The file is decoded and re-encoded at a lower bitrate (64–320 kbps); going from 320 to 128 kbps cuts the size by 60% while staying perfectly listenable for speech and casual music. An optional mono downmix halves stereo voice recordings again. Note that re-encoding a lossy file always costs a little quality, so pick the lowest bitrate that still sounds good to you. Nothing is uploaded.
How to use MP3 Compressor
- 1Drop your MP3.
- 2Choose a lower bitrate (and mono, for speech).
- 3Re-encode and download the smaller MP3.
Why use MP3 Compressor?
- ✓Fitting MP3s under attachment and upload limits.
- ✓Freeing space on players with tiny storage.
- ✓Bitrate slider with size guidance — see exactly what you trade.
Frequently asked questions
How much smaller will my MP3 get?+
Size scales with bitrate: re-encoding a 320 kbps file at 128 kbps makes it 60% smaller; at 96 kbps, 70% smaller. Duration doesn't change — only the data rate does.
Will compressing an MP3 lose quality?+
Yes, slightly — each lossy re-encode discards a little more detail (generation loss). For speech you won't notice down to ~96 kbps; for music try 128–160 kbps first.
Can I make an MP3 bigger to improve it?+
No — re-encoding at a higher bitrate just wastes space. Quality lost in the original encode can never be recovered.
Is my MP3 uploaded?+
No, everything runs in your browser.
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