Convert MP4 to MP3
Extract the audio from an MP4 video as an MP3, right in your browser. No upload.
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MP4
Video and audio are converted entirely in your browser — longer or larger files take more time.
Quality
Why convert MP4 to MP3?
When you only need the sound — a lecture, a podcast recording, a song from a clip — an MP3 is a fraction of the size and plays on every device and in every music app.
MP4 vs MP3 at a glance
| MP4 | MP3 | |
|---|---|---|
| Type | Video container | Audio |
| Compression | Lossy | Lossy |
| Introduced | 2001 | 1993 |
| Created by | MPEG / ISO | Fraunhofer IIS |
| Best for | Sharing video anywhere — phones, web, TVs | Music and podcasts on any player |
What actually happens
An MP4 file is a container that usually holds an H.264 video track and an AAC audio track. Converting to MP3 throws the video away and re-encodes the soundtrack with the MP3 encoder (LAME), so the result plays in every music app, car stereo and old MP3 player.
The audio can't get better than the original soundtrack. If the video was a low-quality phone recording, a 320 kbps MP3 won't add detail — it just makes a bigger file.
Choosing a bitrate
128 kbps is fine for speech: lectures, interviews, podcasts and voice notes. 192 kbps suits most music. 320 kbps is the highest MP3 quality and makes sense only when the source is high quality and you listen on good headphones.
As a rule of thumb, one minute of audio is about 1 MB at 128 kbps and 2.4 MB at 320 kbps.
When there's no sound to extract
Screen recordings and some exported clips have no audio track at all. In that case Localvert tells you there is no sound to extract instead of producing an empty file.
Is it safe?
Yes. This conversion runs entirely inside your browser, and your MP4 file is never sent to a server. Metadata such as location is also removed automatically.
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How to convert MP4 to MP3
- 1Drop your MP4 files onto the box above, click it to choose files, or paste an image with Ctrl+V.
- 2Optionally pick a quality preset, or open fine-tune to set an exact quality or a maximum width and height.
- 3Conversion starts immediately and runs on your own device. Nothing is uploaded, so even large batches start without waiting for a transfer.
- 4Download each MP3 file individually, or grab everything at once as a single ZIP.
Frequently asked questions
How long does it take?
The conversion runs on your own computer. A few minutes of video usually takes seconds; a long video can take a minute or two on an older phone. Nothing is uploaded, so there's no waiting for a transfer.
Can I extract audio from a YouTube link?
No. Localvert only converts files that are already on your device. Downloading from streaming sites usually breaks their terms of service.
Is there a length limit?
The free plan accepts files up to 50 MB, one video at a time. Larger files depend on your device's memory, since the work happens locally.
Is it really free?
Yes. Converting MP4 to MP3 is free with no sign-up and no watermark. The free plan handles several files per batch; an optional premium licence removes ads and raises the limits.
Are my files uploaded anywhere?
No. Your MP4 files are read and converted by your browser on your own device. You can confirm it by opening your browser's developer tools and watching the Network tab while you convert: no file upload ever appears.
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