Compress Audio
Shrink audio files by adjusting bitrate and format — choose MP3, AAC, or OGG output.
100% in your browser — files never leave your device
Why compress audio in your browser?
Large audio files create friction: slow email attachments, storage limits on messaging apps, and long upload times for podcast hosts. Compression reduces file size by re-encoding at a lower bitrate — the perceived quality loss is minimal at 128 kbps or higher for most content.
This tool runs FFmpeg.wasm in your browser, with no server involved. The FFmpeg WASM binary (about 25 MB) downloads from a CDN on first use and is cached for future visits. Compression happens locally — useful for audio containing sensitive or private content you don't want passing through a third-party service.
Choose your output format (MP3 for widest compatibility, AAC for better quality-per-bit, OGG for open-source contexts) and target bitrate, then compress. If your file is already smaller than the target, the original is returned unchanged.
Frequently asked questions
What output formats does audio compression support?
The compressor outputs MP3 (via libmp3lame), AAC in an M4A container (via the FFmpeg aac encoder), or OGG Vorbis (via libvorbis). All three are lossy formats — the tool re-encodes your audio at the selected bitrate. MP3 is the most universally compatible. AAC offers better quality at the same bitrate. OGG is open-source and works well in web contexts.
What bitrate should I choose?
64 kbps is suitable for speech-only content where file size matters most. 128 kbps is a good all-purpose setting for podcasts and general audio. 192 kbps is high quality and appropriate for music or anything where fidelity matters. 320 kbps is near-transparent quality for most listeners and produces the largest files.
Is my audio uploaded to a server?
No. Compression runs in your browser using FFmpeg.wasm — a WebAssembly port of FFmpeg. The WASM binary (about 25 MB) downloads from a CDN the first time you use a media tool, then is cached for future visits. Your audio files never leave your device.
What if the compressed file is larger than the original?
This can happen when the source file is already highly compressed or at a lower bitrate than your selected target. The tool detects this and downloads the original file instead, with a note explaining what happened. Try selecting a lower bitrate.
Can I compress WAV or FLAC files down to MP3?
Yes. The input can be any audio format that FFmpeg can read — including WAV, FLAC, M4A, OGG, and more. Select MP3 as the output format and the desired bitrate, and the tool will convert and compress in one step.