Is my file uploaded to be converted?

No. Decoding and encoding both happen inside this page. You can open your browser's network panel during a conversion and watch nothing leave, which is worth doing if the recording is sensitive.

Why is there no AAC or M4A output?

Your browser can encode AAC frames, and nothing in a browser packs them into an M4A file. Writing that container is a piece of work in its own right, and until it is done here, an M4A from this page would be a file some players refuse to open.

Which bitrate should I choose?

192 kbps for music, 128 for podcasts and 96 for plain speech. Go to 320 only if the file is going to be edited again or you have a reason to keep every bit of the source.

Will converting an MP3 to WAV improve it?

No. The WAV will be ten times the size and will sound exactly like the MP3, because what the MP3 encoder discarded is gone. Converting to WAV is useful when a program will only read WAV, not as a way to recover quality.

How long does a conversion take?

WAV is near instant, since writing it is just copying samples into a header. MP3 takes a few seconds a minute of audio, and the progress bar shows real progress rather than an animation.

Audio Converter

Drop in an audio file and save it as MP3 or WAV. The conversion runs on your own machine, so a voice note or an unreleased mix is never sent anywhere.

Choose an audio file or drop it hereMP3, WAV, FLAC, OGG or M4A, up to 100 MB.

Runs entirely in your browser. Your files are never uploaded.

How to use Audio Converter

1Choose an audio file, or drag it onto the box.
2Pick MP3 with a bitrate, or WAV with a bit depth.
3Change the sample rate or channels if you need to.
4Press convert and save the result.

What goes in, and what comes out

Decoding uses the same engine your browser uses to play audio on a web page, which is why the list of formats it reads is long: MP3, WAV, FLAC and OGG work everywhere, and M4A works wherever the system has an AAC decoder, which covers Windows, macOS, Android and iOS.

Coming out, the choice is MP3 or WAV. Browsers can encode Opus and AAC through WebCodecs, but neither arrives in a file you can hand to someone: the encoder produces raw frames and something still has to wrap them in an OGG or MP4 container. Until that wrapper is written here, offering those formats would mean producing files that half the players reject.

Bitrate, and what it costs

192 kbps is the default because it is where most people stop hearing the difference on music through ordinary headphones. 320 kbps is the ceiling MP3 allows and roughly doubles the file against 192. For speech, 96 or 128 kbps is plenty and saves a lot of space on a long recording.

One thing worth knowing before converting a download: MP3 is lossy, and so are M4A, OGG and the audio in a video file. Converting one lossy format to another decodes it and throws information away a second time, which is audible at low bitrates even when the source sounded fine. Converting from FLAC or WAV has no such problem, since nothing was discarded the first time.

Sample rate and channels

44,100 Hz is what CDs and most music downloads use, and 48,000 Hz is what video does. Converting between them is fine, and there is rarely a reason to go lower unless size matters more than quality.

Folding stereo to mono halves the file and loses nothing on a recording that was mono to begin with, which most phone voice memos and interviews are. It does flatten a music mix, so leave it alone for anything with a stereo image you care about.

Limits

100 MB per file, and 30 minutes of audio. Decoded audio is held uncompressed in memory, so a longer recording would exhaust the tab.
MP3 output is constant bitrate. Variable bitrate needs a different encoder mode than the one available here.
No AAC, Opus or FLAC output, because each needs a container written around the encoded frames.
A file with DRM on it will not open, here or in any browser.

Frequently asked questions

Is my file uploaded to be converted?: No. Decoding and encoding both happen inside this page. You can open your browser's network panel during a conversion and watch nothing leave, which is worth doing if the recording is sensitive.
Why is there no AAC or M4A output?: Your browser can encode AAC frames, and nothing in a browser packs them into an M4A file. Writing that container is a piece of work in its own right, and until it is done here, an M4A from this page would be a file some players refuse to open.
Which bitrate should I choose?: 192 kbps for music, 128 for podcasts and 96 for plain speech. Go to 320 only if the file is going to be edited again or you have a reason to keep every bit of the source.
Will converting an MP3 to WAV improve it?: No. The WAV will be ten times the size and will sound exactly like the MP3, because what the MP3 encoder discarded is gone. Converting to WAV is useful when a program will only read WAV, not as a way to recover quality.
How long does a conversion take?: WAV is near instant, since writing it is just copying samples into a header. MP3 takes a few seconds a minute of audio, and the progress bar shows real progress rather than an animation.