twineconvert

free · in-browser · no upload

MP4 to MP3
Converter

Drop your MP4 file. We'll convert it to MP3 right here in your browser, your file never leaves your device.

or drop your file

Select your file here to get started

or drop your file here.

Accepts .mp4, .m4v

nothing uploaded no file size cap no signup

How it works

Three steps. No upload, no signup.

  1. 1

    Drop your file

    Click the dropzone above or drag a MP4 from your desktop. Files of any size, there's no upload, so there's no upload limit.

  2. 2

    Convert in your browser

    The conversion runs entirely in this tab using JavaScript and WebAssembly. Your file never touches our servers, we don't have any.

  3. 3

    Download

    Get your MP3 the moment the conversion finishes. Convert another, or close the tab.

Files stay on your device

Your file is never uploaded. The entire conversion runs in your browser using WebAssembly. We can't see what you convert because we have no server to see it.

No file size limit

Server converters cap free users at 1-2 GB and gate larger files behind a paid plan. Since nothing uploads, our limit is whatever your browser can handle.

Free, no signup, no ads on conversions

No account required. No watermark on the output. No queue. Drop a file, get a converted file.

Why convert MP4 → MP3

What this conversion is actually for

You want the audio without the video: a song from a downloaded clip, a lecture you'll listen to on a walk, an interview to transcribe, a podcast episode someone sent as a video file. MP3 is tiny, plays on every device, and works in every podcast/music app.

A real example

A 45-minute conference talk was shared as a 1.2GB MP4. You just want to listen on your commute. Convert to MP3, about 40MB, drop it in your podcast app's local files, done.

Troubleshooting

Large video took a long time or ran out of memory.

The whole conversion runs in your browser tab, so a 2GB+ video can hit browser memory limits, especially on mobile. Use a desktop browser for big files, close other tabs, or trim the video to the segment you need first.

There's no audio in the output.

The source MP4 has no audio track (screen recordings without mic, some silent clips). Nothing to extract. Confirm the video actually plays sound in a media player.

Formats involved

About MP4 and MP3

MP4, MPEG-4 Part 14

MP4 is the dominant video container on the web, H.264 video plus AAC audio, in a structure designed for streaming. Every browser, mobile device, smart TV, and editing tool reads MP4. The format is technically a container (not a codec), so two MP4 files can have very different internal codecs, but the H.264+AAC default is what enables universal playback.

How to open

Every video player on the planet, VLC, QuickTime, Windows Media Player, browsers (HTML5 video), iOS, Android, smart TVs, game consoles. Universal.

Full MP4 format guide →
MP3, MPEG Audio Layer III

MP3 is the most widely-supported audio format ever, every device, app, and music player on the planet reads it. It uses lossy compression (typically removing audio frequencies humans can't hear well) to shrink files to about a tenth of their uncompressed size. At 192 kbps and above, the difference vs lossless is inaudible to most listeners on most equipment.

How to open

Every audio player ever made. iOS Music, Android, VLC, iTunes, Windows Media Player, browsers, smart speakers, universal.

Full MP3 format guide →

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FAQ

Common questions

Is this MP4 → MP3 converter really free?

Yes. No signup, no watermark, no daily file count limit. Every conversion runs in your browser, your file never touches our servers because there are no servers.

Where does my file go when I convert it?

Nowhere. The conversion runs entirely in your browser using JavaScript and WebAssembly. Your file is never uploaded to our servers. We don't have any servers handling files, there's nothing for us to log, store, or accidentally leak.

What's the maximum file size?

Whatever your browser can hold in memory. Practically, this means a few hundred MB on most computers, significantly larger than the 1-2 GB caps that server-upload converters charge for. Very large files (multi-GB) may require closing other browser tabs first.

Why convert MP4 to MP3?

Web video, mobile video recording, video sharing. Music files, podcasts, audiobooks, voice recordings. The most common reason to convert is compatibility, MP3 works in places where MP4 doesn't, or vice versa.

How do I open a MP4 file in the first place?

Every video player on the planet, VLC, QuickTime, Windows Media Player, browsers (HTML5 video), iOS, Android, smart TVs, game consoles. Universal.

Does this work offline?

Once the page is loaded, the conversion itself runs entirely offline. The first time you use a tool, your browser downloads the conversion library (a one-time cache). If you reload while offline, the page won't load, but you can install the site as a Progressive Web App for full offline use.

Can I convert multiple files at once?

Single file at a time for now. Batch conversion is on the roadmap, for now, drop one file, download the result, then convert the next.