Audio Converter
Convert audio files between MP3, WAV, OGG, FLAC and AAC online free using FFmpeg in your browser. No sign-up needed — works entirely in your browser.
- First use downloads the ~31MB audio engine once; it is cached after that.
- Practical input limit is about 500MB due to browser memory.
An audio converter changes a sound file from one format to another. This one handles MP3, WAV, OGG, FLAC, M4A and AAC entirely on your device: drop a file in, pick the output format and quality, and download the result. Video files work too — the audio track is extracted. Nothing is uploaded.
Which format should you choose?
| Format | Type | Choose it when |
|---|---|---|
| MP3 | Lossy | You want it to play on absolutely everything |
| WAV | Uncompressed | An editor or DAW demands raw audio |
| FLAC | Lossless | Archiving music with no quality loss but smaller than WAV |
| M4A | Lossy (AAC) | Apple devices, iTunes, and voice memos |
| AAC | Lossy | Better quality than MP3 at the same bitrate, broad modern support |
| OGG | Lossy (Vorbis) | Games, web applications, and open-format projects |
The short version: MP3 for sharing, FLAC for keeping, WAV for editing. If you have no particular constraint, MP3 at 192 kbps is almost always the right answer.
Lossy, lossless, and why direction matters
Audio formats fall into two camps, and confusing them causes most format mistakes.Lossy formats — MP3, AAC, M4A, OGG — permanently discard audio information judged inaudible, which is how they get so small. Lossless formats — FLAC — compress without discarding anything, and uncompressed WAV stores every sample outright.
The consequence is that conversion is not symmetrical. Going from FLAC to MP3 loses information, as intended. Going from MP3 to FLAC or WAV does not recover anything: you get a file three to ten times larger containing exactly the same audible content. Converting between two lossy formats, say MP3 to AAC, is worse still, because the second encoder discards information based on what the first one already threw away. If you need a file in several formats, always convert from the highest-quality original you have rather than from a previous export.
Choosing a bitrate
| Bitrate | Roughly per hour | Best for |
|---|---|---|
| 128 kbps | About 58 MB | Speech: lectures, interviews, podcasts |
| 192 kbps | About 86 MB | Music and general use — the default |
| 320 kbps | About 144 MB | The MP3 ceiling, archiving lossy files |
WAV and FLAC ignore this setting entirely, which is why it disappears when you select them — their size is determined by the source audio rather than by a target rate. A useful trick: because the tool allows re-encoding to the same format, you can drop in a 320 kbps MP3 and export it at 128 kbps purely to shrink a file for email, without changing anything else about it.
Converting audio out of a video
The tool accepts video files as well as audio. Drop one in and the video stream is discarded while the audio track is converted to your chosen format, which is often what you want from a lecture recording, a webinar, or a voice memo your phone saved as video. For more control over that specific job — trimming to a section and previewing before download — the video to MP3 tool is purpose-built for it.
Practical notes
- Work from the best original. Every lossy re-encode costs quality that cannot be recovered.
- Match the format to the requirement, not to what sounds most impressive. WAV is not "better" for listening.
- Keep the tab in the foreground on long files, since browsers throttle background tabs.
- Expect around 500 MB to be the practical input ceiling, set by browser memory.
- Use 128 kbps for anything that is speech. The saving is large and the difference is inaudible.
Related audio tools
To cut a section rather than change format, use the audio trimmer. Thespeed changer adjusts tempo, join audio combines several files into one, and the loudness normaliser evens out a recording whose levels drift. For the reverse direction, extract audio pulls a track out of a video file.
Frequently Asked Questions
Is my audio file uploaded to a server?
No. Conversion runs entirely in your browser through FFmpeg compiled to WebAssembly, so the file is read from your disk into memory and never transmitted. Once the page has loaded you can disconnect from the internet and it still works.Which formats can it convert between?
Six: MP3, WAV, OGG, FLAC, M4A and AAC. Any of them can be the input or the output, and you can also re-encode to the same format, which is the way to change an MP3’s bitrate without changing its container.What bitrate should I choose for MP3?
192 kbps is the balanced default and transparent for most music. Use 320 kbps when quality matters more than size, and 128 kbps for speech such as lectures, interviews and podcasts, where it sounds clear at roughly half the size.Why does the quality setting disappear for WAV and FLAC?
Because neither uses a bitrate. WAV is uncompressed 16-bit PCM and FLAC is lossless compression, so both are determined entirely by the source audio. The bitrate selector only applies to the lossy formats: MP3, OGG, M4A and AAC.Can I pull the audio out of a video file?
Yes. Drop in a video and the video stream is discarded while the audio track is converted to your chosen format. If you want trimming and a preview player as well, the dedicated video to MP3 tool has more options.Does converting MP3 to WAV improve the quality?
No, and this is the most common misunderstanding about audio formats. Converting a lossy MP3 to WAV produces a much larger file containing exactly the same audible information. Detail discarded during the original MP3 encode cannot be recovered.Is there a file size or daily limit?
No daily limit and no account. The practical ceiling is around 500 MB per file, set by how much your browser can hold in memory rather than by any quota we impose. Longer recordings simply take a little more time.Why is the first conversion slower?
The audio engine is roughly 31 MB of WebAssembly and downloads once on first use, after which your browser caches it. Later conversions in the same session start immediately, and audio encoding itself is fast compared with video.