What does Audio Converter do?
Convert audio in your browser between MP3, WAV, OGG, Opus, FLAC and M4A. Set bitrate, sample rate and mono or stereo. Files are never uploaded.
- Price
- Free
- Account
- Not required
- Processing
- Entirely in your browser; your data and files are not uploaded
- Works on
- Any modern browser on desktop, tablet or phone
- Category
- Video and Audio Tools
How to use the audio converter
- Drop an audio file (MP3, WAV, OGG, FLAC, M4A or AAC, up to 100 MB). WebM, MKV and AVI videos also work; only the audio is kept.
- Choose the output format.
- For MP3, OGG, Opus and M4A pick a bitrate. Optionally change the sample rate or convert to mono or stereo.
- Click Convert, play the preview and download.
Worked example
Size of a 3 minute track
MP3 at 192 kbps: 192,000 x 180 / 8 = 4,320,000 bytes (about 4.1 MB). WAV at 44.1 kHz, 16-bit stereo: 44,100 x 2 x 2 x 180 = 31,752,000 bytes (about 30.3 MB). FLAC falls in between, depending on the music.
How it works
FFmpeg decodes the first audio stream and encodes it with libmp3lame (MP3), pcm_s16le (WAV), libvorbis (OGG), libopus (Opus), the native FLAC encoder, or the native AAC encoder in an M4A container. -ar changes the sample rate with FFmpeg's resampler and -ac mixes to mono or stereo. Opus supports only 48, 24, 16, 12 and 8 kHz, so other rates fall back to 48 kHz.
Assumptions
- Converting between lossy formats (for example M4A to MP3) loses a little quality each time.
- Converting a lossy file to WAV or FLAC does not restore quality; it only makes the file larger.
- Only the first audio track is converted, and embedded cover art is not kept.
Frequently asked questions
Are my files uploaded?
No. The file is processed by FFmpeg compiled to WebAssembly, running inside your browser. Only the engine itself is downloaded (once, from cdn.jsdelivr.net); your video, audio or images never leave your device.
Which format should I pick?
MP3 plays everywhere. M4A (AAC) and Opus give better quality at the same bitrate. FLAC is lossless for archiving. WAV is uncompressed and suits audio editors.
Does converting to a higher bitrate improve quality?
No. The output can never be better than the source. A higher bitrate only avoids adding more loss.
Why does the first run take longer?
The first time you use any of the video and audio tools, your browser downloads the FFmpeg engine, about 31 MB. It is stored in your browser, so later runs on this device start without downloading it again unless you clear site data.
Limitations
- FFmpeg runs as single-threaded WebAssembly in the browser, which is much slower than desktop FFmpeg. Processing time depends on the file length, resolution and your device; long HD videos can take many minutes.
- Browsers limit how much memory a page can use. Very long or high resolution files can fail with an out of memory message, especially on phones and tablets.
- Files up to 100 MB are accepted.
- Tags (title, artist) are copied where the output format supports them, but cover art is dropped.