Compress an MP3 file online
Shrink an MP3 by lowering its bitrate, directly in your browser — the file is never uploaded to a server.
or click to select it
Shrink an MP3 file by lowering its bitrate, directly in your browser. Handy when the original file is too large to attach to an email or upload to a platform with a size limit.
Re-encodes the MP3 at a lower bitrate. A 320 kbps MP3 converted to 128 kbps can end up less than half the size, at the cost of a quality loss that's hard to notice on most headphones.
Use cases
- Shrink an MP3 to fit an email attachment size limit.
- Save storage space on a phone with limited memory.
- Prepare music for a platform with a per-file size cap.
How it works
- 1
Upload your MP3
Drop the file in or select it from your device.
- 2
Choose the bitrate
128 kbps is used by default; you can go lower for an even smaller file.
- 3
Download the result
Compare the original and final size before downloading.
Technical details
Runs ffmpeg.wasm with the libmp3lame encoder. Since the original MP3 is already lossy, re-compressing it doesn't recover quality — every re-encode adds a small extra amount of degradation, so it's best to always start from the highest-quality copy you have.
Frequently asked questions
How much smaller does the file get?
It depends on the original and chosen bitrate: going from 320 to 128 kbps shrinks the file by roughly 60%.
Can I get the original quality back afterwards?
No. Lowering the bitrate is irreversible — always keep the original file if you might need higher quality later.