Free Audio Converter

Convert between MP3, WAV, M4A, OGG, Opus and FLAC in your browser, or pull the audio out of a video. Pick the output, pick the bitrate, and nothing gets sent to a server.

The converter is ffmpeg compiled to WebAssembly. It downloads once (30 MB) when you pick your first file, then stays in your browser cache.

A higher bitrate keeps more detail and costs more bytes. 192 kbps is transparent for most music on ordinary gear, 128 is plenty for speech, and 320 is the practical ceiling for MP3.

Your file is processed by your own browser and never uploaded. The engine itself is a one-time 30 MB download the first time you use it, and after that it comes out of your browser cache.

How to use Audio Converter

  1. 1Drop your files onto the box above. Audio and video both work, since the audio track is what gets read either way.
  2. 2Choose an output format, and a bitrate if that format has one. WAV and FLAC do not.
  3. 3Play each result to check it, then download. Take a batch as a single .zip.

Choosing an output, briefly

Most people arrive at an online audio converter already knowing the format they need, because something downstream told them. When that is not the case, the decision is short:

  • MP3 plays on everything ever made. Pick it when you do not control the other end.
  • M4A holds AAC, which sounds better than MP3 at the same bitrate. Pick it for Apple software and modern browsers.
  • Opus is the best of the lossy codecs by a clear margin at low bitrates, and excellent at high ones. Pick it when both ends are yours.
  • FLAC is lossless and roughly half the size of WAV. Pick it to archive.
  • WAV is uncompressed PCM. Pick it because a tool insists, not because it sounds better.
  • OGG holds Vorbis. Pick it for game engines and older open-source tooling.

The rule that matters more than the format

Lossy encoding is not reversible, and it stacks. Every time you convert audio format from one lossy codec to another, the second encoder works from what the first one left behind rather than from the original recording, and makes a fresh set of decisions about what to discard. One hop is usually fine. Four hops through a chain of tools is audible.

The practical consequence is about where you keep things, not about which converter you use. Keep the least-compressed version you have as the source, and generate lossy copies from it when a particular device or platform needs one. If all you have is a lossy file, converting it does not make things worse than they already are, but it does not make them better either.

What this one preserves

Sample rate and channel count come through unchanged. Text metadata such as title, artist and album is carried across where both containers support it. Embedded cover art is not, because artwork lives in the file as an image stream and only the audio is kept.

Everything runs on your own machine. The engine is ffmpeg compiled to WebAssembly, fetched once on your first file and then served from your browser cache.

Frequently asked questions

Which output format should I choose?
MP3 for maximum compatibility. M4A if the destination is Apple software or a modern browser, since AAC is more efficient than MP3 at the same bitrate. Opus if you control both ends and want the best quality per byte. FLAC to archive losslessly. WAV when a piece of software demands uncompressed PCM. OGG mainly for game engines and older open-source tooling.
Can it read video files?
Yes. Drop an MP4, MOV, MKV, WebM or AVI and the audio track is extracted and re-encoded to whatever you picked. The video is discarded, which is why the output is a fraction of the input size.
Does converting between two lossy formats hurt quality?
Yes, a little, every time. MP3 to M4A, M4A to MP3, OGG to MP3: each of those decodes what survived the first encode and lets a second encoder make its own decisions. One hop at a decent bitrate is usually inaudible. Repeated hops are not, which is why a lossless master is worth keeping.
Is the sample rate changed?
No. Whatever the source runs at is what comes out, and a mono file stays mono. This is deliberate: the browser's own Web Audio API would resample everything to your output device's rate, which is why this tool uses a real decoder instead.
How large a file can it take?
Up to 500 MB. The whole container has to fit in the browser tab, so the tool refuses larger files up front rather than letting the tab be killed halfway through.

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