Audio Compressor — Free, Browser-Based
Shrink audio files for email, podcasting, or storage. Re-encode MP3, AAC, OGG, or WAV at a lower bitrate or downsample. Powered by ffmpeg.wasm — your audio stays local.
How to compress an MP3 or audio file in your browser
- Drop your audio file. Drag in an MP3, AAC, OGG, WAV, M4A, or FLAC. First use loads ffmpeg.wasm (~25 MB, cached after).
- Pick a target bitrate. Choose 64 kbps (voice/podcast, smallest), 128 kbps (balanced), or 192 kbps (music, better quality).
- Optional: downmix to mono. For voice memos or podcasts, mono cuts file size in half with no perceptual loss.
- Download compressed audio. Click Compress. A 30 MB file typically shrinks to 5–10 MB depending on settings.
Frequently Asked Questions
- Are my files uploaded?
- No. Compression runs entirely in your browser via ffmpeg.wasm. Files never leave your device.
- How much can it shrink an audio file?
- 60–80% reduction is typical going from 320 kbps stereo to 128 kbps stereo, or 80–90% going to 64 kbps mono.
- Will quality drop?
- Yes — lossy re-encoding always loses some fidelity. 128 kbps is transparent for speech; for music, prefer 192 kbps.
- What formats are supported?
- Input: MP3, AAC, M4A, OGG, WAV, FLAC, OPUS. Output: MP3, AAC, OGG.
- Can I batch compress?
- Yes. Drop multiple files; apply the same preset to all and download as ZIP.
- Is there a length limit?
- No hard limit. 2+ hour files work on most laptops; processing time scales with duration.
Use Cases
- Shrink a voice memo for email attachment
- Compress podcast episodes before upload to RSS hosting
- Reduce a recorded interview to fit Discord/Telegram upload limits
- Re-encode a high-bitrate WAV to MP3 for portable players
- Downmix stereo voice recordings to mono to save space