MP3 converter

The converter accepts any audio or video file your browser can decode. In practice that covers:

• Video: MP4, MOV (iPhone videos), M4V, WebM and most MKV files. The soundtrack is extracted and the picture is dropped.
• Audio: M4A and AAC (iPhone voice memos, iTunes), WAV, FLAC, OGG and OPUS, and MP3 itself if you want to change the bitrate.

Chrome and Edge can decode the widest range of formats. If a file won't open, it's usually because the browser doesn't know its codec, the file is damaged, or it has no audio track. Copy-protected files (DRM) can't be converted.

There are dedicated pages for the most common pairs, such as M4A to MP3, WAV to MP3 and MOV to MP3; they use the same engine with the file picker set to that format.

Bitrate	Good for	Size per minute (stereo)
96 kbps	Speech, podcasts, audiobooks	about 0.7 MB
128 kbps	Casual music listening	about 1 MB
192 kbps	Good-quality music (default)	about 1.4 MB
256 kbps	Very good quality	about 1.9 MB
320 kbps	Best MP3 quality	about 2.4 MB

Size per minute is simply bitrate × 60 seconds ÷ 8, so it applies to any MP3 encoded at a constant bitrate.

For music, 192 kbps is hard to tell apart from the original on most headphones and speakers. Go to 256 or 320 kbps if you are archiving music or will edit it again later. For recorded speech, 96 kbps (or 128 kbps) is plenty, and ticking Mono halves the file size again.

Converting a low-quality file to a higher bitrate doesn't add quality back: a 128 kbps MP3 re-saved at 320 kbps just gets bigger.

You can add as many files as you like, in one go or one after another. Each file keeps its name with the new extension, so interview.m4a becomes interview.mp3. If two files would end up with the same name (for example song.wav and song.flac), the original format is added to the second one so nothing gets overwritten.

One file downloads directly as an MP3. Two or more are packed into a single ZIP file, which you can open on any computer or phone. After converting you can play a single result right on the page to check it.

Stereo keeps separate left and right channels. Mono mixes them into one channel, which is all you need for a voice recording, a lecture or a phone call. A mono MP3 at the same bitrate sounds the same for speech and is half the size of a stereo one at half the bitrate, so for podcasts mono at 96 kbps is a common, efficient choice.

Keep stereo for music: mixing the channels can make some instruments quieter or change the stereo image.

Everything happens in your browser: your files are decoded and encoded on your own device and are never uploaded to a server. That also means there's no upload wait and no file-size limit set by a server.

The browser has to hold the whole decoded audio in memory, which takes roughly 10 MB per minute of stereo sound. Files over about 200 MB, or very long recordings, can be slow on older computers and may fail on a phone. If that happens, use a desktop browser or split the file first.