Video & audio converter
MP4 to MP3 Converter
Pull the soundtrack out of an MP4 video and save it as a high-quality MP3 (variable bitrate, around 190 kbps). Free, online, no sign-up.
Tested by Thiago · Updated
Free, no sign-up · Sent over HTTPS · Files are deleted from our server automatically after 30 minutes
How to convert MP4 to MP3
- Add your files: drag them into the box above, or click "Choose files".
- Click "Convert to MP3" and wait a few seconds while we process them.
- Download your MP3 files. Uploaded files are deleted right away, and converted files are removed from our server after 30 minutes.
Why convert MP4 to MP3?
Converting MP4 to MP3 keeps only the sound of a video, which is perfect for listening to talks, lessons, interviews or your own recordings on the go. MP3 files are small and play on any phone, car stereo or music app. ConvertKiwi uses high-quality variable bitrate encoding (usually about 130 to 175 kbps), so voices and music stay clear.
- You recorded a lecture, meeting or interview on video and only need the audio.
- You want to listen to your own video content like a podcast.
- You need an audio file to edit or to send to someone for transcription.
What decides the size of the MP3?
Only the sound. The picture is thrown away completely, so the resolution of the video makes no difference: 4K or 720p, only the audio track ends up in the file. What matters is how long the recording is and how rich the sound is.
The encoder uses a variable bitrate: quiet speech gets fewer bits per second, dense music gets more. In our test, a 30-second 1080p clip of 57 MB with a voice-like track became an MP3 of 0.40 MB, averaging about 107 kbps. With music and other dense sound, our tests landed at about 130 to 175 kbps, roughly 1.0 to 1.3 MB per minute, so even a long lecture stays far smaller than its video.
Before you convert: a quick checklist
- Make sure the video actually has sound. Screen recordings made with the microphone off often have no audio track at all, and then there is nothing to extract.
- The MP3 is named after your video file, and a title saved inside the MP4 is copied into the MP3, so your music app shows it.
- The volume is not changed. A recording that is too quiet stays quiet, so raise it later in an audio editor if needed.
- The audio cannot get better than the original. If the voice sounds muffled in the video, it will sound the same in the MP3.
Tips for the best result
- Only convert videos you own or have permission to use.
- If you plan to edit the audio professionally, MP4 to WAV gives you an uncompressed file.
- For other video formats like MOV, WEBM or MKV, use the MP3 converter, which accepts them all.
- Converting several talks at once? Add them together and download each MP3 when it is ready.
About these formats
MP4: The most widely supported video format. It plays on phones, browsers, TVs and social networks, with good quality at a reasonable size.
MP3: The most popular audio format. It compresses sound to a small size while keeping good quality, and it plays on any device.
Frequently asked questions
What quality is the MP3?
We use high-quality variable bitrate (LAME V2, usually about 130 to 175 kbps), which is transparent for most listeners.
Does it keep the full length of the video?
Yes. The MP3 has the same duration as the video.
Can I convert a large MP4?
Yes, up to 200 MB per file. You will see the upload and conversion progress with the time left.
Why does my MP4 fail to convert to MP3?
The most common reason is a video without an audio track, such as a silent screen recording. You will see a "Conversion failed" message. Play the video with sound first to check that there is something to extract.
Can I turn the MP3 back into a video?
Not back into the original video, because the picture was not kept. The MP3 to MP4 tool can create a new video from the audio, with a plain background or a cover image you choose.