MP4 to MP3 converter
Extract the audio from any video as MP3, M4A or WAV, right in your browser. Choose the quality, trim it if you like, and download. Your file never leaves your device.
4 steps, no signup
- 01
Choose a video
MP4, MOV, WebM, MKV and most other video files work. The file stays on your device.
- 02
Pick a format
MP3 plays everywhere. M4A copies the original audio with no quality loss, in seconds, when it is AAC (most MP4s). WAV is uncompressed for editing.
- 03
Trim if you want
Optionally set a start and end time to keep just part of the audio.
- 04
Convert and save
Press Convert. The audio is extracted in your browser and downloads when it's done.
Short answer: choose a video file above, keep MP3 selected, pick a bitrate (192 kbps suits most uses) and press Convert. The audio is extracted in your browser with FFmpeg and you download an MP3. Pick M4A instead for a lossless copy of the video's own audio track, or WAV for editing. Nothing is uploaded.
What this MP4 to MP3 converter does
Sometimes you only need the sound: a lecture to listen to on a walk, a voice memo recorded as video, the music from your own clip, or audio to edit into a podcast. The MP4 to MP3 converter pulls the audio track out of a video file and saves it as MP3, M4A or WAV. It runs entirely in your browser with ffmpeg.wasm, so nothing is uploaded and private recordings stay on your device.
MP3, M4A or WAV?
| Format | Quality | Size per minute (stereo) | Best for |
|---|---|---|---|
| MP3 128 kbps | Good for speech | ~1 MB | Podcasts, lectures, voice notes |
| MP3 192 kbps | Very good | ~1.4 MB | Music, general use |
| MP3 320 kbps | MP3 maximum | ~2.4 MB | High-quality sources |
| M4A (copy) | Identical to the video's audio | Same as the original track | Keeping full quality, fastest |
| WAV | Uncompressed | ~10–11.5 MB | Editing in Audacity, DAWs, video editors |
Sizes follow from the bitrate: 192 kbps × 60 seconds ÷ 8 = 1.44 MB. WAV keeps the source's sample rate: 16-bit stereo is about 10.6 MB per minute at 44.1 kHz and 11.5 MB at 48 kHz, the usual rate for video.
Why M4A is often the smartest choice: most MP4 videos store their audio as AAC. M4A simply copies that track into its own file, with no re-encoding, so there's zero quality loss and it finishes in seconds. Choose MP3 only when a device or app specifically needs it.
How the conversion works
The tool runs ffmpeg.wasm, the open-source FFmpeg media toolkit compiled to run inside a web page. For MP3 it drops the video stream and encodes the audio with the LAME MP3 encoder at the bitrate you choose; for M4A it copies the audio stream untouched; for WAV it decodes to uncompressed PCM. The engine (about 30 MB) downloads once per visit.
A worked example
Take a 4-minute phone video of a talk, recorded as MP4. Converting it to MP3 at 128 kbps gives a file of about 3.7 MB (128 kbps × 240 seconds ÷ 8 = 3.84 million bytes). At 192 kbps it is about 5.5 MB. To keep only the Q&A at the end, type 2:45 in Start and leave End empty: the MP3 then covers 1 minute 15 seconds. Choosing M4A for the same file usually finishes fastest, because the AAC track inside the MP4 is copied rather than encoded.
Troubleshooting
- "Write times like 90, 1:30 or 1:02:03." The start or end time has a typo. Use seconds, or minutes:seconds.
- "The end time must be after the start time." Swap or fix the two times.
- "This file has no audio track to extract." The video is silent. Screen recordings often are.
- "FFmpeg couldn't read the audio in this file." The file is damaged or uses an unusual codec. Re-export it as MP4 from the app that made it and try again.
- The M4A message says it was encoded to AAC. The video's audio wasn't AAC, so a straight copy wasn't possible. The tool encoded it at 192 kbps instead.
- It stalls on a phone. Very large videos can run out of browser memory. Trim the range, close other tabs or use a computer.
Common uses
- Lectures and webinars you want to listen to offline.
- Voice memos and interviews recorded on a phone camera.
- Your own videos: pull the soundtrack or voiceover for reuse.
- Transcription: many transcription tools accept audio files more readily, and they're far smaller than video.
- Podcast editing: export WAV for clean editing, then publish as MP3.
Copyright
Converting a file you made, or have permission to use, is fine. Extracting music or audio from other people's videos to redistribute is usually a copyright issue, whatever the tool. This converter works only on files already on your device, and it doesn't download from YouTube or other platforms.
Related tools
To get a video in the first place, the Reddit video downloader and Twitch clip downloader save public clips as MP4. To make a looping image from a video, use video to GIF, and to shrink a video before sending it, the video compressor.
Privacy
Your file is processed inside your browser and never uploaded. The only network download is the FFmpeg engine, from the jsDelivr CDN.
Last checked and updated: . Everything on this page runs in your browser; nothing you enter is sent anywhere.