Free MP3 Compressor
Use Free MP3 Compressor, review the result, and keep the original until the output is checked.
How to use Free MP3 Compressor
- Add up to 50 audio files; a video file dropped in here has its soundtrack taken out instead.
- Drag Bitrate (kbps) down from 128 to make the file smaller, or tick Variable Bitrate (VBR) in Advanced Compression Options and use Quality (0-9) instead, where 9 is the largest and cleanest.
- Leave Normalize Audio ticked to level quiet recordings, or untick it to keep the original dynamics.
- Press Convert All and read the size of each result before Download All.
What Free MP3 Compressor actually does to your file
Every run decodes the MP3 and encodes it again, so quality can only move down from the source - raising the bitrate above the original does not bring anything back, and a 128 kbps file re-encoded at 320 kbps is simply a larger file with the same loss. A typical spoken-word recording drops far at low bitrates while music needs 96-128 kbps before artefacts stop being audible. Normalize Audio applies loudness normalisation, so expect the output level to differ from the input.
Free MP3 Compressor FAQ
What does Free MP3 Compressor do?
Our free MP3 compressor lets you easily reduce audio file size online. Adjust bitrate, sample rate, or channels to get the perfect balance between size and quality—fast, secure, and no software needed.
Which files work with Free MP3 Compressor?
This category commonly supports MP3, WAV, AAC, OGG, and M4A. Use the accepted file types shown in the uploader, because support varies by browser and by the engine behind each tool.
Does compressing reduce the quality?
Yes, size comes from discarding detail. Start near the middle of the quality range and look at the result; if it is not small enough, lower the quality rather than re-compressing the same file several times, because each pass loses more.
Will my original file be changed?
No. The work is done on a copy in this tab by your browser's audio decoder and a WebAssembly build of ffmpeg, and the result arrives as a separate download, so your original is still there if you need it.
How is my file processed?
It is not uploaded. The processing is done locally by your browser's audio decoder and a WebAssembly build of ffmpeg, so the practical ceiling is your device's memory and the limit shown beside the uploader - no queue, no account, no copy on a server.
Are my files uploaded to your servers?
Many EditTools pages process files in your browser, so data never leaves your device. When server processing is required, files are handled over encrypted connections and removed according to our privacy policy.