MP3 Compressor
Reduce MP3 file size by re-encoding at a lower bitrate. Free and 100% client-side.
Drag & drop files here, or browse
Processed on your device. Nothing is uploaded
Automate this. An open tab can compress whole folders via the Local API - still zero uploads.
Local API →How to use MP3 Compressor
- 01Add files
Choose files or drop them here
- 02Settings
Settings · Runs on your device
- 03Download
Processed on your device. Nothing is uploaded
What is a MP3 (MPEG-1 Audio Layer III) file?
MP3 is the world's most compatible lossy audio format. It compresses audio to a fraction of its original size while keeping quality most listeners find indistinguishable.
- Developed by
- Fraunhofer IIS
- Initial release
- 1993
Frequently asked questions
How does MP3 Compressor work?
Drop your file, pick a quality target and hit Compress. The optimized file downloads straight from your browser. Nothing is uploaded.
Is MP3 Compressor free?
Yes, completely free with no watermarks or limits, because all processing runs on your own device.
Are my files safe?
Your files never leave your device. Compression happens locally in your browser via WebAssembly.
Is there a file size limit?
We impose no fixed limit. The practical ceiling is your device's free memory, since processing happens locally. Most conversions work comfortably with files up to a few hundred megabytes, and image or document conversions handle much more.
Does it work on my phone?
Yes. The converter runs in any modern browser on Windows, macOS, Linux, Android and iOS. No app installation is required.