How to convert MP4 to MP3
- 1
Add the video
Choose an MP4 or M4V file, or drag it onto the box above. The tool checks at once that the video has a sound track. - 2
Pick a quality
Choose 128, 192 or 320 kbps. 192 kbps is selected by default. - 3
Convert and download
Press Convert to MP3 and follow the progress bar. You can cancel at any time. The MP3 gets the same name as your video.
Which bitrate should you choose?
The bitrate sets how much data each second of sound gets, so it decides the file size. It cannot add quality the video never had.
- 128 kbps suits speech such as a lecture or a talk, at about 58 MB per hour.
- 192 kbps is a good default for mixed sound, at about 86 MB per hour.
- 320 kbps is for music, at about 144 MB per hour.
Very low sample rates set a lower ceiling: the MP3 format stops at 160 kbps for a 16 kHz recording, so the encoder uses the nearest bitrate it allows. Surround sound is mixed down to stereo.
Turn a video lecture into something you can listen to
This suits lecture recordings and webinars. An MP3 is far smaller than the video, plays in almost any app, and is easy to listen to on a walk or a commute. Your video is not changed: the tool reads it and writes a new file, and the MP3 runs as long as the sound track in the video.
If you want the lecture as text, you can upload the recording to Spirelight transcription and get a draft with speakers and timestamps, which you check against the audio yourself.
Limits and privacy
The conversion happens in your browser. Your video is not uploaded, and it is gone from the page when you close the tab. Because the video is read a piece at a time, its size is rarely the problem. The finished MP3 is what stays in memory until you save it, and it can be up to 1 GB, which is about 11 hours at 192 kbps.
Keep the tab open while it works. Copy-protected videos, such as purchased films, cannot be read. It works in current Chrome and Safari on a computer. On a phone it depends on the browser and the free memory, so start with a short file.