Filenary

MP4 to MP3 Converter

Convert MPEG-4 video files to MP3 audio right in your browser — free, private and with no size limit.

Drop your file here

or click to browse

Choose File

On first use, a ~30 MB conversion engine is downloaded to your browser (one time only).

This file is processed in your browser and never uploaded to a server.

How to convert MP4 to MP3

  1. 1Drop your MP4 file into the box above, or click to choose it from your device.
  2. 2Click Convert. The conversion runs locally in your browser — nothing is uploaded.
  3. 3Download your new MP3 file as soon as it's ready.

Why convert MP4 to MP3?

MP4 files can be larger than newer formats like WebM at the same quality. MP3 plays on every device, car stereo and app, with small file sizes.

Why people make this conversion

Pulls the soundtrack out of any MP4 — the quickest way to turn a screen or call recording into a podcast-style audio file.

The size math: MP4 vs MP3

A minute of MP4 video weighs about 9 MB; its soundtrack alone as MP3 is 1.4 MB. Extracting audio shrinks the file about 6.4× smaller.

What is MP4?

MP4 is the most compatible video format, using H.264 video and AAC audio. It plays on every phone, browser, TV and social network.

  • MIME type: video/mp4
  • Standardized: 2001 (MPEG-4 Part 14)
  • Usual codecs: H.264 or H.265 video plus AAC audio
  • The universal container: phones, TVs and editors all accept it

What is MP3?

MP3 is the most popular audio format. It compresses music and speech into small files that play on any device.

  • MIME type: audio/mpeg
  • Standardized: 1993 (MPEG-1 Audio Layer III)
  • Common bitrates: 128–320 kbps
  • Plays on essentially every device made since 1993

Frequently asked questions

Is this MP4 to MP3 converter free?
Yes, it's completely free with no sign-up, no watermark and no daily limits.
Are my MP4 files uploaded to a server?
No. The conversion happens entirely inside your browser, so your files never leave your device.
Is there a file size limit?
Filenary sets no limit — even files over 1 GB work. The only practical limit is your device's memory.
Will converting MP4 to MP3 reduce the quality?
MP3 uses lossy compression, so the file becomes smaller with a small, usually invisible, loss of detail. Settings are tuned to keep the result sharp.
Can I convert several MP4 files at once?
This converter handles one file at a time. When it's done, click Start over to convert the next MP4 file.
Does it work on iPhone, Android, Mac and Windows?
Yes. It runs in any modern browser — Chrome, Safari, Edge or Firefox — on phones, tablets and computers, with nothing to install.

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Copy the code below and paste it into any page. It's free, needs no sign-up, and files are processed in your visitors' own browsers.