Convert MP4 to MP3

Turn an MP4's soundtrack into a standalone MP3 file at the bitrate you choose, in your browser.

Drop your files here

.mp4, .m4v · up to 300 MB

Choose files

128 kbps192 kbps320 kbps

More settings

Sample rateChannelsLoudness

How to Convert to MP3

1
Add your MP4 file
Up to 300 MB, including the .m4v files iTunes and some cameras produce. The picture is never decoded, so the limit here is much higher than for tools that touch every frame.
2
Pick an MP3 bitrate
192 kbps is plenty for the AAC track inside a typical MP4; 128 keeps a lecture small, and 320 only pays off when the source audio was high quality to begin with.
3
Click Convert and download
The MP3 keeps the video's file name and length and weighs roughly 1.4 MB per minute at 192 kbps.

What is inside an MP4, and why it cannot just be renamed

An MP4 is a container: a video stream, usually H.264 or HEVC, and next to it an audio stream, almost always AAC, each with its own timing table. Renaming the file to .mp3 changes nothing inside it, and a music player that expects a bare stream of MP3 frames finds a box of unrelated data instead, which is why the renamed file is silent or refused. Converting means opening that box, taking only the audio track and encoding it as MP3. The video stream is skipped with a single flag and never decoded, so the limits here are much higher than on tools that have to touch every frame.

AAC in, MP3 out: what changes

The AAC track inside an MP4 is already compressed, so converting it to MP3 is a second lossy step. At 192 kbps or above the loss is inaudible on normal playback gear, and MP3 buys you a file that every car stereo, phone, voice recorder app and ancient player accepts. If you want the sound exactly as it was and your player reads AAC files, Audio from Video can copy the track out byte for byte without re-encoding at all. Come here when the destination insists on MP3, which it usually does.

File size and bitrate, in numbers

MP3 size depends on bitrate and length, not on the video's resolution: a minute of audio is about 1 MB at 128 kbps, 1.4 MB at 192 and 2.4 MB at 320, so an hour-long recording comes out around 60, 85 or 145 MB. For speech (lectures, podcasts, meetings) 128 kbps is plenty. For music, 192 is the everyday choice, and 320 only helps when the source was better than 192 to begin with; encoding a 128 kbps AAC track at 320 produces a bigger file, not a better one.

If your file isn't actually MP4

Video containers look alike from the outside, and an MKV or MOV file renamed with an .mp4 extension is common. This page checks the real signature of the file rather than trusting its name, and if it turns out to be a different container, it offers to continue straight on the general video-to-MP3 tool with the same file and the same bitrate already picked, with no re-uploading and no starting over.

Nothing about your MP4 is uploaded

The container is read and the audio encoded on your own device by a WebAssembly build of ffmpeg, and the picture is never decoded, which is why this page takes files up to 300 MB. There is no upload, no account and no queue, and closing the tab clears everything.

Frequently asked questions

Which bitrate should I pick for an MP4?

192 kbps for most MP4s: the AAC track in a phone or camera video rarely holds more detail than that. Use 128 for lectures and meetings, where the file size matters more, and 320 only for music you know was encoded at a high bitrate.

Does converting MP4 to MP3 lose quality?

A little, because the AAC track is decoded and re-encoded as MP3. At 192 kbps the difference is inaudible on normal equipment. If your player accepts AAC files, Audio from Video copies the track out untouched instead.

How big will the MP3 be?

About 1 MB per minute at 128 kbps, 1.4 MB at 192 and 2.4 MB at 320, whatever the video's resolution: a 4K recording and a phone clip of the same length give MP3s of the same size.

What if my file is really an MKV or MOV, not MP4?

The page detects the real container and offers a one-click continue on the general video-to-MP3 tool with the same file and bitrate, and nothing to re-upload.

What if the MP4 has no sound at all?

You'll get a clear message that there's no audio track to extract, with a link to add a soundtrack to the video first if you meant to make one.

Why not just rename the .mp4 to .mp3?

Because the extension does not change the bytes: an MP4 is a container with a video stream and an AAC audio stream, and an MP3 player expects a bare stream of MP3 frames. Renamed files play as silence or are refused; converting extracts the audio and encodes it properly.

Does this work on an iPhone?

Yes, in Safari: an MP4 from the camera roll or Files converts on the phone itself, and the result is saved through the Share sheet. iPhone recordings are usually .mov, though, and those belong on Video to MP3, which accepts MOV directly.