MP4 to MP3 Converter
Pull the soundtrack out of a video — a phone clip, a screen recording, a recorded lecture — and save it as MP3 for listening or WAV for editing. It all happens in your browser, so the video never leaves your device.
128 kbps is plenty for speech; 192–320 kbps for music.
WAV is uncompressed 16-bit audio at the original sample rate — about 10 MB per minute.
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How to convert MP4 to MP3
- Under Save as, pick MP3 or WAV. For MP3, choose 128, 192 or 320 kbps; 192 is preselected.
- Drop one or more videos into the box, or tap Choose videos. Audio files such as M4A, WAV or FLAC are accepted too.
- Files are converted one after another, with a percentage on each row. Press Play to listen, then Download — or use Download all (ZIP) once two or more are done.
Which MP3 quality should you pick?
The sound inside a video is already compressed — phones and screen recorders usually store it as AAC — so an MP3 can preserve what is there but never add to it. Raising the bitrate beyond what the source holds only makes the file bigger.
128 kbps is plenty for speech: lectures, meetings, interviews, sermons. 192 kbps, the default, suits music and mixed content for everyday listening. 320 kbps is the highest bitrate MP3 allows; it pays off only when the original sound is genuinely good, such as a concert filmed on a capable camera.
When WAV is the better choice
WAV keeps the sound uncompressed, as 16-bit PCM at the sample rate of the original. Pick it when an editing program, a transcription service or a sampler asks for WAV, or when you will process the audio further and want to avoid a second round of lossy compression. A WAV is seven to eight times the size of a 192 kbps MP3 — around 10 to 11.5 MB per stereo minute.
WAV cannot bring back detail that the video's soundtrack lost when it was recorded; it simply makes sure nothing more is lost on the way out.
MP3 and WAV sizes, worked out
Audio size is plain arithmetic: bitrate × duration. One minute at 128 kbps is 128,000 bits × 60 seconds ÷ 8 = 960,000 bytes, a little under 1 MB. WAV is not compressed, so its size depends on the sample rate and the number of channels rather than on a bitrate.
| Output | Per minute | One-hour recording | Good for |
|---|---|---|---|
| MP3 128 kbps | ≈ 0.96 MB | ≈ 58 MB | Lectures, meetings, interviews, voice notes |
| MP3 192 kbps (default) | ≈ 1.44 MB | ≈ 86 MB | Music and mixed content for everyday listening |
| MP3 320 kbps | ≈ 2.4 MB | ≈ 144 MB | Music from a high-quality source |
| WAV from 44.1 kHz stereo | ≈ 10.6 MB | ≈ 635 MB | Editing, mastering, software that insists on WAV |
| WAV from 48 kHz stereo | ≈ 11.5 MB | ≈ 691 MB | The same jobs, when the video's sound is 48 kHz |
These figures use decimal megabytes (1 MB = 1,000,000 bytes). The list under the converter counts in binary units, so the same file reads a few percent smaller there. A mono source gives a mono file, which halves the WAV size; an MP3's size is set by its bitrate either way.
What happens to the sound on the way out
- One soundtrack. If a video carries several audio tracks — two languages, say, or a director's commentary — the main one is converted: the track marked as default, or otherwise the one with the highest bitrate. The rest are skipped, and the row says how many were left out.
- Surround becomes stereo. 5.1 and other multichannel sound is mixed down to two channels; mono stays mono.
- Sample rate. MP3 keeps the original rate up to 48 kHz, the most the format supports; anything above that, such as 96 kHz audio from some cameras and field recorders, is brought down to 48 kHz. WAV keeps the original rate, whatever it is. A low rate also caps the MP3 bitrate — the format allows at most 160 kbps at 16–24 kHz and 64 kbps at 8–12 kHz — so a phone-call recording at 8 kHz comes out at about 64 kbps whichever quality you pick; the row says so when that happens.
- The whole file. The soundtrack is converted from start to finish. To keep only part of it, trim the result afterwards in an audio editor.
- File names. clip.mp4 becomes clip.mp3 or clip.wav. Running an MP3 through again — to lower its bitrate, for instance — adds “-converted”, so the original is never overwritten.
- Changing your mind is cheap. Switch format or bitrate after adding files and everything already converted is redone with the new setting. The choice is remembered for the next time you open the page.
What people pull audio out of videos for
- Lectures and meetings. A two-hour recorded class becomes an MP3 of about 115 MB at 128 kbps that plays on any phone with the screen off.
- Interviews and transcription. Speech-to-text and captioning services commonly accept MP3 or WAV, and an audio file uploads in a fraction of the time the video would need.
- Editing. Bring the WAV into an audio or video editor to clean up noise, balance levels or lay the sound under different pictures.
- Rehearsals and voice memos. A song filmed at practice, or a note that was recorded as a video, is easier to loop, share and keep as plain audio.
- Older players. Many car stereos and portable players read MP3 from a USB stick or memory card and nothing else.
If it's the video itself that is too big to send, the video compressor shrinks it to a size in MB instead; for a short silent loop to drop into a chat or a slide, try Video to GIF.
Only files you already have
The converter works on files you select from your own computer or phone. It does not accept links and cannot download anything from video sites. Before reusing the sound from someone else's video, make sure you have the right to — your own recordings, a class where recording is allowed, or material whose licence permits it.
Other ways to get audio out of a video
- Mac: QuickTime Player saves the sound alone with File › Export As › Audio Only. The result is an AAC file with the .m4a extension, not an MP3.
- iPhone: the Shortcuts app's Encode Media action has an Audio Only switch that saves a video's sound as .m4a. For an MP3, open this page in Safari 26 or later instead.
- Windows: Windows Media Player can rip audio CDs to MP3, but it has no option for saving the soundtrack of a video file. VLC media player, which is free, can: use Media › Convert / Save with the Audio – MP3 profile.
- Audacity opens the sound of video files once its optional FFmpeg library is installed — handy when you also want to trim or clean up the audio.
Renaming .mp4 to .mp3 doesn't convert anything: the file is still an MP4 with the wrong name, and players that trust the extension will refuse it.
Frequently asked questions
How do I convert MP4 to MP3?
Choose MP3 and a quality below the drop box, add the MP4, and download the .mp3 when its row says Done. You can add many videos at once; they are processed in order.
Is converting MP4 to MP3 lossless?
No. MP3 is a lossy format, and the soundtrack inside an MP4 is normally lossy AAC already, so the MP3 is a copy of a copy. At 192 kbps or higher, most listeners can't tell the difference in everyday use. Choose WAV if you need to avoid the second lossy step.
Can I convert MOV, WebM or MKV to MP3?
Yes. The converter reads MP4, MOV, M4V, 3GP, MKV, WebM and MPEG-TS files (.ts, .mts, .m2ts), and audio files such as M4A, MP3, WAV, Ogg, Opus, AAC and FLAC. AVI, WMV, FLV and RMVB are not supported.
Is my video uploaded anywhere?
No. When you add the first file, the page fetches its audio converter from capypix.com; reading the video and encoding the sound then happen on your own device. The file's name, length and content are never sent anywhere.
Why does it say the video has no audio track?
The file holds pictures only. Screen recordings made with the microphone and system sound switched off, clips converted from GIFs and some exported animations have no soundtrack at all, so there is nothing to extract.
Can Windows Media Player convert MP4 to MP3?
Not directly. It can rip CDs to MP3, but it cannot save the soundtrack of a video file as MP3. Use this converter or VLC instead; changing the file extension does not convert the file.
How do I extract audio from a video on iPhone?
Open this page in Safari, tap Choose videos and pick the clip from your photo library, then save the MP3 to the Files app. It needs Safari 26 or later, which can decode compressed audio; older versions show a notice above the file list. If an .m4a file is enough, Apple's Shortcuts app can make one with the Encode Media action.
Can I extract just part of the audio?
Not here: the whole soundtrack is converted. Trim the MP3 or WAV afterwards in an audio editor; Audacity is free and can cut out a section.
Can I paste a link to a video instead?
No. The tool only reads files from your own device and never fetches anything from video sites. Save your own recording to the device first, then add it here.
Why does a file fail with a message about decoding the sound?
The browser has no decoder for that audio format. It happens with some surround formats, such as AC-3 or DTS tracks in camera files and TV recordings, and with any compressed audio in browsers that lack WebCodecs audio support. Trying the latest Chrome or Edge on a computer is the best next step.
Is there a length or size limit?
Not for MP3: long videos just take longer, and the video is read in pieces rather than loaded whole. A WAV is built in memory, so it is capped at about 2 GB, roughly three hours of 48 kHz stereo; for anything longer, choose MP3.