What's inside an MP4, and what you're taking out
An MP4 is a container holding at least one video track and usually one audio track, most often AAC. Converting MP4 to MP3 means pulling out that audio track, decoding it and encoding it as MP3, the format every phone, car stereo, smart speaker, DJ app and media player has understood since the late 1990s.
The video is simply dropped, which is why the MP3 is a fraction of the MP4's size: a 10-minute 1080p video may be 150 MB or more, while its 192 kbps MP3 is about 14 MB.
Why is the MP3 192 kbps?
The audio in phone videos and social media downloads is usually AAC at 96–160 kbps, and AAC is more efficient than MP3, so 192 kbps MP3 is the point where the conversion keeps essentially everything the source had. Going to 320 kbps would make the file two-thirds bigger without bringing back detail that was never in the video.
The MP3 is encoded with LAME, the reference open-source MP3 encoder, at a constant 192 kbps. Constant bitrate files are the most compatible: older car stereos and some hardware players struggle with variable bitrate MP3s.
Popular reasons to convert
Some of the most common jobs:
- Turning a recorded lecture, sermon, webinar or meeting into a podcast-style file for listening on the go.
- Saving a song or a live performance you filmed at a concert.
- Extracting a voice-over or narration to reuse in another edit.
- Making a sound clip for a presentation, a game or a notification sound.
- Getting the audio of a TikTok, Instagram or Facebook video. If you have the link rather than the file, our MP3 downloaders do it in one step.
Can I convert MOV, WEBM or MKV to MP3?
Despite the name, the converter accepts nearly any video: MOV from an iPhone, WEBM screen recordings, MKV, AVI, 3GP from older phones, and more. As long as the file has an audio track, the result is a standard MP3. If the video has several audio tracks (for example, different languages), the first one is used.
If the file has no audio at all, which is common with screen recordings made without a microphone and with silent GIF-style clips, you'll see a message instead of an empty MP3.
Fast, private and on any device
Extracting audio is light work: most videos convert in a few seconds even on a phone, because only the sound is decoded. Everything runs in your browser with ffmpeg compiled to WebAssembly, so the video never leaves your device. That matters when it's a private recording such as a family event or a work call.
The MP3 takes your video's file name, so it's easy to find in Downloads. On iPhone it lands in Files → Downloads, where you can play it or share it to another app.
How do I get the MP3 into my music app?
On iPhone, the Files app plays MP3s directly, so for one-off listening you're done once the file is in Downloads. Adding it to the Music app's library still requires a computer: sync it with Finder on a Mac or iTunes on Windows. On Android, apps like YouTube Music and most music players pick up MP3s in your Music or Downloads folder automatically.
For car stereos, copy the MP3 to a USB stick formatted as FAT32, which nearly every car reads. Large exFAT and NTFS sticks often aren't recognised by older head units.