Audio Converter
Switch audio files between MP3, WAV, FLAC, and more. Preview the result before you download.
Drop your audio here
or click to browse
How it works
This converts audio between MP3, WAV, OGG, FLAC and AAC in your browser, using ffmpeg compiled to WebAssembly. Drop a file, pick a target format, convert. Nothing is uploaded.
For MP3, OGG and AAC you also choose a bitrate, defaulting to 192k. WAV and FLAC have no bitrate control because neither throws anything away - WAV stores raw samples and FLAC compresses them losslessly.
More detail
What each format is for
- MP3, via
libmp3lame. Plays on everything ever made. Pick it when compatibility matters more than efficiency. - AAC. Better quality than MP3 at the same bitrate, and the default in the Apple ecosystem and in video containers.
- OGG, Vorbis. Comparable to AAC and unencumbered, but less widely supported by consumer hardware.
- WAV. Uncompressed PCM, roughly 10 MB per stereo minute. Some audio tools and speech APIs only accept this.
- FLAC. Lossless and compressed, about half the size of WAV with bit-identical audio. The right choice for keeping a master copy.
The one thing to get right
Conversion cannot add back what a previous encoder removed. Going from a 128k MP3 to FLAC gives you a lossless copy of lossy audio: larger, no better. Going from MP3 to MP3 at a higher bitrate is worse than useless, because you pay a second generation of loss for a bigger file.
Convert down from the best source you have, not sideways between lossy formats. If you only have the lossy file and the destination needs a different container, accept the single generation and move on.
Limits
The ffmpeg core is about 25 MB and is fetched once per session from a public CDN, so the first conversion is slower. Input is capped at 500 MB, and the browser's memory is usually the real ceiling on very long files.
Questions
Are my files uploaded?
No. ffmpeg runs as WebAssembly inside the page and reads the file through the browser's File API. The only network request is the initial fetch of the ffmpeg core.
What bitrate should I use for MP3?
192k is a reasonable default and what this uses unless you change it. 128k is fine for speech and podcasts. Going above 256k rarely earns its size unless the source is lossless and you are listening on good equipment.
Will converting to FLAC improve a low-quality MP3?
No. FLAC reproduces exactly what it is given. You get a bit-perfect copy of the compression artefacts, several times larger than the MP3 you started with.
Why is my WAV file so big?
Because WAV stores raw uncompressed samples. Roughly 10 MB per minute of stereo audio is normal. If you want lossless without the size, use FLAC instead.