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Audio Compressor
Audio Compressor
What is this tool?
A browser-based audio re-encoder built on ffmpeg.wasm. Pick a target bitrate, sample rate and mono/stereo setting, and it compresses your audio to MP3 while showing a live estimated output size.
When to use it
- Shrinking a voice recording before emailing it
- Reducing a podcast episode's file size before uploading
- Fitting an audio file under a platform's upload size limit
- Converting a large WAV recording to a smaller MP3
- Cutting file size for a project that doesn't need studio-quality audio
How to use it
- 1Upload an audio file
- 2Choose a target bitrate (kbps) — lower means smaller but lower quality
- 3Choose a sample rate and mono or stereo output
- 4Check the live estimated output size
- 5Click Compress, then download the resulting MP3
Frequently asked questions
How much smaller will my file get?
It depends on the source and your chosen bitrate — the tool shows a live size estimate before you commit, so you can compare settings.
Will compression reduce audio quality?
Yes, MP3 at a lower bitrate is lossy — pick a higher bitrate if quality matters more than file size.
Why does this take a moment to start?
The first compression loads the ffmpeg.wasm encoding engine (~30MB) into your browser; it's cached after that.
Is my audio uploaded to a server?
No — encoding runs entirely in your browser via WebAssembly.