FileReshape
EN

MP4 to MP3 converter

FileReshape's MP4 to MP3 converter takes the sound track out of a video and saves it as an MP3 at 128 to 320 kbit/s, using FFmpeg inside your browser. The video is not uploaded. It also reads MOV, WebM, MKV and AVI files. Videos without sound, and copy-protected films from streaming services, cannot be converted.

Did a file not convert correctly? E-mail [email protected], ideally with a small sample file, and it will be fixed.

Key facts

MP4 to MP3: why convert

A lecture you recorded, a music video from your own camera, a voice note that a messaging app saved as a video, or a podcast published only as a video: often only the sound is needed. This converter reads the MP4 in your browser, takes the first sound track and encodes it as MP3 with the LAME encoder, the same one used by Audacity and most desktop converters. Choose 192 kbit/s for music or 128 kbit/s for speech to get a smaller file. The title and artist stored in the video are copied into the MP3 tags. Because nothing is uploaded, a one-hour video does not have to travel to a server first: the conversion starts as soon as the engine is loaded and usually takes a few seconds per minute of sound.

How to convert MP4 to MP3

  1. Drop the MP4 video in the box, or click to choose it.
  2. Check the duration and sound track shown, and choose the MP3 quality.
  3. Click Convert to MP3; the MP3 downloads when it is ready.

What changes when you convert

The sound is already compressed

The sound in an MP4 is almost always AAC, which is lossy like MP3. Converting it to MP3 is a second lossy step, so pick a bit rate at least as high as the original (the summary shows the sound codec). 192 kbit/s keeps music transparent for most listeners; a higher setting cannot add detail that the video's sound does not have.

Videos without a sound track

Screen recordings made without the microphone, GIF-like clips and some exported videos have no sound at all. The tool reads the file first and tells you straight away instead of producing a silent MP3.

Streaming videos and DRM

Films and series downloaded in the Netflix, Disney+ or Apple TV apps are encrypted and cannot be read by any converter. Only use the tool for videos you made or have the right to use.

Large files and phones

The video is read in pieces, so even files of one or two gigabytes work on a computer. On a phone, very long videos may be slow because the browser gets less memory and processor time.

About the formats

MP4

MP4 (MPEG-4 Part 14) is the most common video file format. Phones, cameras, YouTube, WhatsApp and every computer and TV use it. An MP4 is a container: the picture inside is usually compressed with H.264 or H.265 (HEVC) and the sound with AAC, and the same file can also hold subtitles, chapters and a cover image.

  • The format was standardised in 2003 and is based on Apple's QuickTime format, which is why MP4 and MOV files are so alike.
  • H.264 video with AAC sound plays on practically every device made in the last 15 years.
  • A minute of phone video in 1080p is typically 100–200 MB; in 4K it is often 350–500 MB.
  • The "faststart" layout puts the index at the beginning, so a video can start playing before it is fully downloaded.

MP3

MP3 is the most widely supported audio format. It was developed at the Fraunhofer Institute in Germany and standardised in 1993, and it plays on every phone, computer, car stereo and website. MP3 makes music about a tenth of its CD size by leaving out sounds people hardly hear.

  • 128 kbit/s is fine for speech and podcasts; 192–320 kbit/s is used for music.
  • The last MP3 patents expired in 2017, so the format is free to use everywhere.
  • Title, artist, album and cover art are stored in ID3 tags at the start of the file.
  • MP3 is lossy: every new encode loses a little more, so convert from the original when you can.

Frequently asked questions

Is my video uploaded?

No. FFmpeg runs as WebAssembly inside your browser tab and reads the file from your own device. Only the engine itself (32 MB) is downloaded the first time, from the jsDelivr network.

Can I convert MOV, WebM or MKV videos too?

Yes. The converter accepts the common video formats; it only needs a sound track it can decode, such as AAC, MP3, Opus, Vorbis or AC-3.

Which bit rate should I choose?

128 kbit/s for lectures, interviews and podcasts, 192 kbit/s for music, and 256 or 320 kbit/s if you want the highest MP3 quality and do not mind a larger file. A minute at 192 kbit/s is about 1.4 MB.

Can I keep only part of the sound?

This tool converts the whole sound track. Trim the MP3 afterwards in an audio editor such as Audacity.

Related converters