MP4 to MP3 Converter
Pull the soundtrack out of MP4, MOV, MKV, WebM or AVI and save it as MP3, M4A or WAV at the bitrate you pick. The video is processed in your browser.
The interactive tool loads here when JavaScript runs.
About this toolWhat is MP4 to MP3 Converter?
Drop a video, choose MP3, M4A or WAV, and this page saves only the audio. It takes the first audio track from MP4, MOV, MKV, WebM, AVI, FLV, WMV, MPG and most other video files, throws the picture away and writes an audio file with the same name, so "Lecture 3.mp4" becomes "Lecture 3.mp3".
For M4A there is a shortcut. Nearly every MP4 and iPhone MOV already stores its sound as AAC, and M4A is simply AAC in an audio-only MPEG-4 file. When the tool sees AAC in the source it copies the track byte for byte instead of re-encoding it, which is lossless and takes a second or two even for an hour of video.
Conversion runs on ffmpeg compiled to WebAssembly inside your browser. The first extraction downloads that engine, about 32 MB, from the jsDelivr CDN; the video itself never leaves your computer.
- MP3 (LAME), M4A (AAC) and WAV output
- Bitrates from 96 to 320 kbps and a mono switch
- Lossless AAC copy into M4A when the source allows it
- Reads MP4, MOV, MKV, WebM, AVI, FLV, WMV, MPG and more
- Batch extraction with progress, cancel and audio preview
- Video stays on your device; the engine is loaded from a CDN once
How to use MP4 to MP3 Converter
- Drop one or more video files on the upload area, or record the 3-second sample.
- Pick MP3, M4A (AAC) or WAV, and a bitrate for MP3 or M4A. Turn on Mono for speech to halve the size.
- For M4A, leave "Copy AAC audio without re-encoding" on unless you specifically need a new bitrate.
- Click Extract. Each row shows the source audio codec, progress and the output size.
- Play the result in the preview and click Download, or Download all.
Worked examples
Recorded lecture to MP3 for a phone
Input
52-minute MP4 screen recording, MP3 at 96 kbps, Mono on
Output
lecture.mp3 of about 37 MB (96,000 bits x 3,120 s / 8)
Speech does not need stereo or a high bitrate; the same audio at 192 kbps stereo would be twice the size with no audible gain.
Music video to M4A without quality loss
Input
clip.mp4 with AAC 160 kbps audio, M4A, copy on
Output
clip.m4a, the original AAC stream in an audio-only file
Because the track is copied, the M4A is bit-identical to the audio in the video and is ready almost instantly.
Background and insight
MP3 output always means a fresh encode with the LAME encoder: the AAC (or Opus, or Vorbis) audio in the video is decoded and compressed again as MPEG-1 Audio Layer III. Each lossy generation discards a little more, which is why the M4A copy is the better choice when your player supports it. MP3 is still the answer for car stereos, older MP3 players, some podcast hosts and anything that says "MP3 only".
Bitrate decides the size and, up to a point, the quality. MP3 tops out at 320 kbps. For speech such as lectures, meetings and podcasts, 96 or 128 kbps mono is plenty; for music, 192 kbps is the usual sweet spot and 256 to 320 kbps is effectively transparent for most listeners. A higher bitrate than the source audio had buys nothing: if a phone recorded AAC at 128 kbps, a 320 kbps MP3 of it is just a bigger file.
WAV is there for editing and transcription. Audio editors, samplers and speech-recognition tools often want plain PCM, and decoding once to WAV avoids stacking another lossy generation before you edit.
Common use cases
Podcasts and talks
Turn a recorded webinar, interview or conference talk into an MP3 you can listen to on a commute.
Transcription
Extract WAV or a small mono MP3 from a meeting recording before sending it to a speech-to-text service.
Music from your own videos
Save the soundtrack of a concert clip or a song you recorded on your phone as a separate audio file.
Video editing
Pull the audio out as WAV to clean it up in Audacity or a DAW, then lay it back under the picture.
Tips and limitations
- Only the first audio track is extracted. Files with several language tracks or a commentary track will give you the default one.
- If a file says it has no audio track, it really has none: screen recordings made without a microphone are a common cause.
- M4A copy is skipped when you turn on Mono, because changing channels needs a re-encode.
- Extracting from a protected (DRM) video is not possible; ffmpeg cannot decode encrypted streams, and you should not try to work around that.
- Long videos are fine because only the audio is encoded, which is fast; the limit is the size of the video file the browser has to read, about 1.9 GB.
Frequently asked questions
Does extracting MP3 from MP4 lose quality?
A little, because MP4 audio is usually AAC and turning it into MP3 means decoding and encoding again. At 192 kbps or more it is hard to hear. If you want no loss at all, choose M4A with copy on, which keeps the original AAC stream untouched.
What bitrate should I choose for MP3 audio from a video?
Use 96 or 128 kbps with Mono for speech, 192 kbps for most music, and 256 or 320 kbps if you want to be sure. Going above the bitrate of the audio in the video does not improve it; it only makes the MP3 bigger.
Can I extract audio from MOV, MKV, WebM or AVI as well as MP4?
Yes. Anything ffmpeg can read works, including iPhone MOV files, MKV downloads, WebM screen recordings from a browser, AVI, FLV, WMV and MPG. The tool uses the first audio track and ignores the picture and subtitles.
Is the video uploaded to extract the audio?
No. The ffmpeg engine is downloaded once from the jsDelivr CDN and runs inside your browser tab. The video is read from your disk into that engine and the audio file is created locally, so it works for private recordings.
Why is M4A sometimes much faster than MP3?
When the video already contains AAC, an M4A can be made by copying the audio stream into a new file with no encoding at all. MP3 always needs the audio to be decoded and compressed again with the LAME encoder, which takes longer.
Can I keep only part of the audio?
This tool extracts the whole track. To cut a section, extract it first and then trim it with the Audio Format Converter, or trim the video with the Video Converter before extracting. Desktop editors such as Audacity also trim precisely.
Is there an in-depth guide to MP4 to MP3 Converter?
Yes. “WAV, MP3, AAC, FLAC and Opus: Audio Formats Explained” covers the background, how it works, common pitfalls and worked examples. Read the full guide.
Related Tools You May Like
Free, in-browser tools that pair well with this one.