How to use
- Select or drop an audio file into the dropzone.
- Choose a target bitrate — 64k, 96k, 128k or 192k.
- Click Compress and wait for the engine to process it.
- Download your smaller compressed MP3.
Frequently asked questions
What audio formats can I compress?
You can load common audio files such as MP3, WAV, M4A, AAC, OGG and FLAC. Whatever you feed in, the tool re-encodes it and gives you back a compressed MP3.
Is my audio uploaded to a server?
No. Everything runs locally in your browser with ffmpeg.wasm, so your audio never leaves your device and nothing is ever uploaded.
Which bitrate should I choose?
Lower bitrates like 64k and 96k create the smallest files with lower quality, ideal for voice or podcasts. Higher bitrates like 128k and 192k keep more quality but save less space.
Why is the first run slow?
The first run downloads the ~30 MB ffmpeg engine to your device. After that it is cached and runs offline, so later compressions start much faster.
Is there a file size limit?
There is no fixed limit, but since compression happens entirely in your browser, very large files use more memory and take longer. Most music and voice recordings compress quickly.
Will compressing reduce the audio quality?
Lowering the bitrate discards some data, so a lower bitrate means smaller size and slightly lower quality. Choose 128k or 192k when you want to keep quality close to the original.
About this tool
Free online audio compressor. Reduce MP3 and audio file size by lowering the bitrate (64k, 96k, 128k, 192k). Runs 100% in your browser — no uploads, fully private.