Convert MP4 to MP3

What MP4 to MP3 does

Extracting audio means keeping only the sound track of a video. MP4 to MP3 reads the video with FFmpeg, skips the picture and encodes the sound as MP3 with the LAME encoder. The audio is always re-encoded, even when the video already contains MP3 sound, so you can choose the bitrate. Because no video frames are encoded, this is much faster than converting a video.

It is useful when you only need the music, speech or interview from a recording, since a small MP3 is easier to store, play and share than the full video.

How to use MP4 to MP3

1. Drop your MP4 files into the box, or click to choose them.
2. Pick the output format and any options.
3. Click Convert. The conversion runs on your device.
4. Download each file, or all of them at once as a ZIP.

When to use MP4 to MP3

• Save the audio of a recorded lecture, webinar or meeting as MP3 to listen to it on a phone while commuting.
• Take the song out of a music video you made, to share it on platforms that accept only audio files.
• Extract an interview from a camera recording so it can be transcribed or edited in an audio program.
• Keep the soundtrack of a family video as a small MP3 when the full video is too large to send.

Settings explained

Bitrate

Sets the MP3 bitrate from 64 to 320 kbps. The default of 192 kbps suits music, while 96 or 128 kbps suits speech and gives much smaller files. At 192 kbps and above, audio is saved at 44.1 kHz.

Mono

Mixes the sound into a single channel. Choose it for lectures, voice recordings and phone videos, where stereo adds nothing. Leave it off for music and films with stereo effects.

What changes when you convert MP4 to MP3

Only the audio track of the MP4 file is kept. The video picture is dropped, which makes the MP3 file a small fraction of the original size.

Format comparison

What is MP4?

MP4 (MPEG-4 Part 14) is a video format introduced by MPEG in 2001. It uses lossy compression. Files use the .mp4 extension.

MP4 is a container format defined in part 14 of the MPEG-4 standard and based on Apple's QuickTime file format. It holds separate video, audio and subtitle tracks. The video is usually H.264 or H.265, sometimes AV1, and the audio is usually AAC. The codecs inside, not the container, decide the quality.

MP4 with H.264 video and AAC audio is the most compatible choice for sharing video. It works well for uploads to social media and video sites, playback on phones and TVs, and video embedded in websites.

Compatibility depends on the codecs inside. An MP4 with H.265 or AV1 video may not play on older devices or in every browser. H.264 and H.265 are patented codecs. Editing and saving again with a lossy codec reduces quality.

MP4 plays in all major web browsers, on Windows, macOS, Android and iOS, on smart TVs and game consoles, and in players such as VLC. H.264 MP4 is the safest choice when you do not know the device.

What is MP3?

MP3 (MPEG-1 Audio Layer III) is an audio format introduced by Fraunhofer IIS in 1993. It uses lossy compression. Files use the .mp3 extension.

MP3 is audio layer III of the MPEG-1 and MPEG-2 standards, developed mainly at the Fraunhofer Institute in Germany. It uses a model of human hearing to remove sounds that most listeners cannot hear, which made music files about ten times smaller than CD audio. Its patents have now expired.

MP3 is the best choice when an audio file must play on every possible device, for example podcasts, music collections, audiobooks and voice recordings shared with many people. A bitrate of 192 to 320 kbps suits music well.

MP3 is less efficient than AAC or Opus, so it needs a higher bitrate for the same quality. At low bitrates, cymbals and high tones can sound watery. Converting from one lossy format to another always loses some quality.

MP3 plays in all web browsers, on Windows, macOS, Linux, Android and iOS, and on car stereos, smart speakers, TVs and older portable players. It is the most widely supported audio format.

Why use FansBond MP4 to MP3

Most online converters upload your files to their servers. FansBond MP4 to MP3 does the work inside your browser instead, using WebAssembly and modern browser APIs. Your files stay on your device, which is safer for private photos, contracts and unreleased work, and it is often faster because nothing has to upload or download.

There are no queues, no watermarks and no account. Once the page has loaded, the tool keeps working even on a slow connection.

Tips for the best result

• Use 128 kbps or lower for long speech recordings. A one-hour talk is about 58 MB at 128 kbps and about 29 MB at 64 kbps.
• The whole video file is loaded into the browser's memory. For very large videos, close other tabs first, especially on a phone.
• If you see a message that there is no audio track, play the original in a video player. Screen recordings and some exported clips are silent.
• To keep only part of the sound, shorten the video first with the trim tool, then extract the audio from the shorter clip.

How MP4 to MP3 works in your browser

Video and audio are processed with FFmpeg, the open-source media toolkit behind most video software, compiled to WebAssembly. Video is encoded with H.264 for MP4, MOV and MKV, VP8 for WebM, and audio with AAC, MP3, Vorbis, Opus or FLAC depending on the format.

WebAssembly FFmpeg runs on your device's processor without a server. It is slower than a native desktop app, so a long video can take a few minutes. Keep the tab open until the progress bar finishes.

Privacy and security

Most online converters upload your files to a server, process them there and keep a copy for some time. MP4 to MP3 works differently: the code is downloaded to your browser once, and your files are read and written only on your device.

You can check this yourself: after the page has loaded, turn off your internet connection and the tool still works. This makes it safe for contracts, IDs, medical records, private photos and unreleased work.