WebM vs MP3
| Property | WebM | MP3 |
|---|---|---|
| Full name | WebM (based on Matroska) | MPEG-1 Audio Layer III |
| File extensions | .webm | .mp3 |
| Created by | Fraunhofer IIS and MPEG | |
| Introduced | 2010 | 1993 |
| Compression | Lossy (VP8, VP9 or AV1) | Lossy |
| Codecs inside | VP8, VP9 or AV1 video; Vorbis or Opus audio | MP3, usually 128–320 kbps |
| Typical size | — | About 1 MB per minute at 128 kbps, 2.4 MB at 320 kbps |
| Opens on | Every current browser and Android; many editors, older iPhones and TVs do not play it | Every phone, computer, car stereo, speaker and app |
| Best for | Video on websites and browser screen recordings | Music and podcasts that must play anywhere |
Why convert WebM to MP3?
WebM files are not always video. Browser voice recorders, some messaging apps and many web audio tools save sound as WebM with Opus audio, and many audio players, transcription services and podcast hosts will not accept it. MP3 is the universal fallback.
The converter handles both cases: it pulls the audio track out of a WebM video, or converts an audio-only WebM directly. Opus is a very efficient codec, so a low-bitrate WebM voice recording may become a larger MP3. That is expected: MP3 needs more bits for the same clarity. For speech, 96–128 kbps mono MP3 sounds clean and stays small.
If you recorded the audio with our Voice Recorder, you can also save it in another format there. To shorten the MP3, use the Audio Trimmer.