Convert Always

Runs on your device

MP4 to MP3 converter

Need MP3 instead of MP4? Add the file below and the converter handles the rest — batch conversion included, no account and no watermark.

Drop files here

Up to 20 files, 100.0 MB each. Conversion happens on your device — nothing is uploaded.

What is MP4?

MP4 is the universal video container, almost always carrying H.264 video with AAC audio. If a device plays video at all, it plays MP4.

Standardised by MPEG in 2001, based on Apple's QuickTime container.

  • The most compatible video format in existence
  • Hardware-accelerated decoding on virtually every chip
  • Streams progressively, so playback starts before the download finishes

What is MP3?

MP3 is the lossy audio format that made digital music portable. Psychoacoustic compression removes sound the ear is unlikely to register, cutting size by roughly ten to one.

Standardised by the Fraunhofer Institute and MPEG in 1993.

  • Plays on every device ever built with a speaker
  • Small files at 128-320 kbps, ideal for podcasts and music
  • Mature tooling, tagging and streaming support everywhere

Why convert MP4 to MP3?

  • MP3 is the better fit for music, podcasts and voice recordings meant for sharing or streaming, while MP4 is built for sharing, uploading and playing video anywhere.
  • It sidesteps the main drawback of MP4: h.264 is less efficient than modern AV1 or HEVC.
  • You gain plays on every device ever built with a speaker.
  • Compatibility improves where it counts: Every phone, browser, car stereo, DAW and media player.

Quality and file size after conversion

Both formats are lossy, so this is a re-encode rather than a copy. Quality is set by the target bitrate or quality level rather than by the source, and each additional round trip costs a little fidelity. Convert once, from the highest-quality file you have.

Compatibility

MP4 opens in Every browser, phone, smart TV, console and editor. MP3 opens in Every phone, browser, car stereo, DAW and media player.

If the file has to work for someone else, choose the format their software already understands rather than the one with the best specification.

Limitations to know about

  • MP3 is lossy — the conversion is one-way and re-editing the output repeatedly will degrade it.
  • Extra tracks, chapters and subtitles inside the MP4 file are not carried into the MP3 output.
  • Lossy — the discarded detail can never be recovered
  • No multichannel surround in practice, and no lossless mode

When to keep MP4 instead

MP4 is still the right choice for sharing, uploading and playing video anywhere. Keep the original alongside the converted copy whenever you might need to re-export at a different size or quality — conversion is quick, but recovering discarded detail is impossible.

How to convert MP4 to MP3

  1. 1

    Drag your MP4 file onto the drop zone above, or click to browse. Up to 20 files can be queued at once.

  2. 2

    MP3 is already selected as the output format — change it in the dropdown if you need something else.

  3. 3

    Press Convert and watch the per-file progress bar.

  4. 4

    Download the MP3 result, or grab everything as a single ZIP when you converted a batch.

Frequently asked questions

Is this MP4 to MP3 converter free?

Yes. Every conversion on Convert Always is free, with no account, no watermark and no daily download cap. The site is funded by advertising rather than subscriptions.

Are my MP4 files uploaded to a server?

No. MP4 to MP3 runs entirely inside your browser using WebAssembly, so the file never leaves your device. You can even disconnect from the internet after the page loads.

Will converting to MP3 reduce the quality?

Both formats are lossy, so this is a re-encode rather than a copy. Quality is set by the target bitrate or quality level rather than by the source, and each additional round trip costs a little fidelity. Convert once, from the highest-quality file you have.

Can I convert several MP4 files at once?

Yes. Add up to 20 files to the queue, convert them in one pass and download the results individually or bundled into a single ZIP archive.

What is the maximum MP4 file size?

Files up to 100 MB each are accepted. Browser-side conversions are limited mainly by your device's memory, so very large video files convert faster on a desktop than on a phone.

Does it work on mobile?

Yes. The converter is built mobile-first and works in Safari and Chrome on phones and tablets. Heavy media conversions are slower on mobile hardware but still run locally.

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