Audio Converter
Convert audio files to MP3, WAV, OGG, M4A or FLAC in your browser, or extract the sound of a video. Batch conversion, no upload, no sign-up.
Most MP3 and WAV conversions run instantly with your browser's own decoder. OGG, M4A, FLAC and formats your browser can't read use FFmpeg compiled to WebAssembly: the first time, this downloads about 30 MB, which your browser then keeps in its cache.
How to convert audio files
- Drop one or more files on the drop zone, or click it to choose them. Audio files (MP3, WAV, M4A, AAC, OGG, Opus, FLAC, WMA, AIFF…) and videos (MP4, MOV, MKV, WebM) are accepted, up to 300 MB each.
- Under Convert to, pick the output: MP3 (plays everywhere), WAV (uncompressed), OGG Vorbis, M4A (AAC) or FLAC (lossless).
- For MP3, OGG and M4A, choose a Bitrate. Optionally change the Sample rate and the Channels (Mono or Stereo); Same as the source keeps them unchanged.
- Press Convert. A progress bar follows each file, and each finished file gets its own Download button. Download all saves every result; Clear empties the list.
You can press Convert again after changing the settings to convert the same files to another format.
How the conversion works
Two engines run in your browser, and neither uploads anything.
- Fast path for MP3 and WAV. When your browser can read the input format (MP3, WAV, AAC, Ogg, Opus and FLAC in current browsers), the file is decoded with the Web Audio API and encoded straight away: WAV as 16-bit PCM, MP3 with the LAME encoder. This takes a few seconds even for long files.
- FFmpeg for everything else. OGG, M4A and FLAC output, and inputs your browser can’t read (WMA, AIFF on some browsers, AMR, some video files), go through FFmpeg compiled to WebAssembly. The first time, your browser downloads the engine, about 30 MB, from this site; after that it comes from the cache. FFmpeg runs in a background worker so the page stays responsive.
When FFmpeg does the conversion, tags such as title and artist are copied if the output format supports them; the fast path writes files without tags. Cover art is never kept.
Which format should I choose?
| Format | Type | Typical use |
|---|---|---|
| MP3 | Lossy | Maximum compatibility: phones, cars, old players |
| M4A (AAC) | Lossy | Apple devices, better quality than MP3 at the same bitrate |
| OGG Vorbis | Lossy | Games, Linux, web; open and royalty-free |
| FLAC | Lossless | Archiving music at about half the size of WAV |
| WAV | Uncompressed | Editing, audio software, CDs |
For lossy formats, 192 kbps suits most music, 128 kbps is fine for speech, and 256–320 kbps is for demanding listening. Converting from one lossy format to another (MP3 to M4A, for instance) never improves quality: the losses of both add up, so choose a generous bitrate. Converting a lossy file to FLAC or WAV makes it bigger without restoring anything, but gives you a copy that won’t degrade with further edits.
Frequently asked questions
Are my files uploaded to a server?
No. Both engines run on your device. The only download is the FFmpeg engine itself, the first time it is needed; your audio never leaves your computer or phone.
Why does the first OGG, M4A or FLAC conversion take longer?
It downloads the FFmpeg WebAssembly engine, about 30 MB. Later conversions start immediately, as the browser keeps it in its cache.
Can I extract the audio from a video?
Yes. Drop an MP4, MOV, MKV or WebM file: only its first audio track is converted, and the picture is dropped.
Is there a file size limit?
Yes, 300 MB per file, because the whole conversion happens in your browser’s memory. On phones, very large files can fail for lack of memory; the tool then shows a message.
Which bitrate should I use for MP3?
192 kbps is a good default. Use 128 kbps for voice or to save space, and 320 kbps if you want the best MP3 quality.
Related tools
- Audio Cutter Cut and trim MP3, WAV, M4A, OGG or FLAC files in your browser. Select on the waveform, add fades and export to MP3 or WAV. No upload.
- Volume Booster and Normalizer Increase the volume of an audio file in dB, normalize its peak or its loudness, with a limiter that prevents clipping. Export to MP3 or WAV in your browser.
- Audio Speed and Pitch Changer Slow down or speed up an MP3 without changing the pitch, or transpose a song by semitones. Preview, then export to MP3 or WAV, all in your browser.