MP3 Compressor
Re-encode MP3 audio at a lower bitrate to shrink file size for podcasts, voice memos, and music sharing.
Drop or click to select (mp3)
First run downloads ~30MB ffmpeg engine; subsequent runs are instant. Everything stays in your browser.
About this tool
MP3 has been the universal audio format for decades. Even though newer formats like AAC and Opus are technically superior, MP3 still plays on virtually any device on Earth. That ubiquity is exactly why compressing MP3 files is still useful: a smaller file uploads faster, fits more easily into a podcast feed, and stretches your storage further.
Our MP3 Compressor uses ffmpeg running in your browser via WebAssembly to re-encode your audio at a lower bitrate. The file never uploads — everything happens locally on your CPU, which is important for confidential interviews, voice memos, and unreleased music alike.
Pick a bitrate manually or specify the exact MB you want to hit. The tool handles the math.
Why use it
- Runs locally in your browser — your audio never uploads.
- Powered by ffmpeg.wasm for professional-grade re-encoding.
- Target a specific file size in MB.
- Free, unlimited, no watermark, no signup.
How to use it
- 1Upload your MP3
Drop a .mp3 file into the upload area. There's no length limit beyond your device's memory.
- 2Pick a bitrate or target MB
128 kbps is great for podcasts and voice memos. 192 kbps is a comfortable music default. Lower bitrates make smaller files.
- 3Download the compressed audio
The new MP3 saves to your downloads folder. The original remains untouched.
Common use cases
- Sending voice memos and interview recordings via email.
- Trimming podcast episodes before uploading to a host.
- Saving space on phone music libraries.
- Preparing audio for embedded HTML5 players on websites.
- Compressing audiobook chapters for portable players.
- Reducing lecture and meeting recordings for sharing.
Tips for best results
Spotify Free, YouTube, and most podcast apps stream at 128 kbps. Going much higher rarely makes a noticeable difference on phone speakers or earbuds.
Spoken-word audio sounds fine at 22 kHz mono, halving the file again on top of bitrate savings.
If you're archiving a music master, keep the original WAV. Re-compressing a compressed file always degrades it.