Convert MP4 to MP3
Take the sound out of a video and keep it as an MP3 that plays anywhere — in the car, on a phone, in any music app. The video is never stored, however long it is.
- Never stored
- No queue, no waiting
- No signup, no watermark
How it works
Add your video
Drop an MP4 — or a MOV, MKV, WEBM, AVI, FLV or WMV file. It opens straight away, and its length and sound track are shown at once.
Choose the quality
192 kbps suits music, 128 kbps is plenty for speech, and 320 kbps keeps everything the video had.
Download the MP3
One file, named after the video, ready for any player.
What comes out, and what it costs
The sound in a video is almost always AAC, so this is a transcode between two lossy codecs rather than a copy. They use different filter banks and disagree about what is inaudible, which means the MP3 spends bits reproducing decisions the AAC encoder made, artefacts included. The result is a little worse than either codec would be from a clean source — the ordinary price of a format that plays in every car — and it is why the bitrate this page reports for the video's own sound track is the number worth matching rather than beating.
There is one case that costs nothing at all. A few MP4 and MKV files carry an MP3 track rather than an AAC one, usually older recordings and older exports; when that happens the packets are lifted straight out of the container into the MP3 file with nothing decoded, and what you get is bit for bit the track that was in the video.
Otherwise the encoding is at a constant bitrate, so the size is plain arithmetic rather than a guess: an hour at 192 kbps is about 86 MB, whether the hour is an action film or a lecture.
When you want something else
ffmpeg offers one setting this page does not: variable bitrate. Asking it for -q:a 2 produces a file smaller than a 192 kbps constant-rate MP3 at the same quality, because quiet passages are cheap and loud ones are not, and it is the better default for anything you mean to keep. A folder of lecture recordings is that one command in a loop, which here would be an afternoon of clicking.
Frequently asked questions
Is my video stored anywhere?
No. Nothing is sent anywhere — no queue, no copy of your file on someone's server, and it works on a plane with the Wi-Fi off.
Which bitrate should I choose?
192 kbps is the sensible default: close to transparent for music at about 1.4 MB a minute. Take 128 kbps for lectures, podcasts and anything spoken, and 320 kbps when you want the largest, safest file — though an MP3 can never be better than the sound already in the video.
Can I convert a two-hour film?
Yes. Only the sound track is decoded, so a long film converts at many times real speed and uses very little memory. The progress bar shows how far along it is, and you can stop it at any point.
What if the video has no sound?
You are told so rather than handed a silent file. Some screen recordings and camera clips genuinely have no sound track at all.
Which video formats work?
MP4, M4V, MOV, MKV, WEBM, AVI, FLV, WMV, MPEG and MPEG-TS, including old camera and Flash files whose sound is stored as AC-3, Windows Media Audio, PCM or MP2 — all of it is decoded and written out as MP3.
Would a lossless format be better?
If you want to edit the sound later, choose WAV or M4A in Extract Audio: MP3 re-compresses what is already compressed, which is fine for listening and less good for editing. For listening, MP3 is the one format every device plays.
Good to know: MP3 supports up to two channels, so 5.1 surround sound is folded down to stereo. A copy-protected film (a DVD rip with its protection intact, or a downloaded rental) cannot be opened by any browser tool.
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