How to convert MP4 to MP3
- Drop a video on the box above or click Choose a video. MP4, MOV, WebM and audio files such as M4A work, as long as your browser can play them.
- Choose the quality: 128 kbps is the standard, 192–320 kbps is higher, and 64–96 kbps is enough for speech. Tick Mono for a lecture, interview or voice recording: speech needs only one channel, and the whole bit rate is then spent on it, so a low setting still sounds clear.
- Click Convert to MP3. The tool reads the sound of the video, then encodes it, showing the progress. You can cancel at any time.
- Listen to the result in the player, then click the download button. The file is named after your video, for example
holiday.mp3.
Everything is done in your browser. Your video and the MP3 are never uploaded, and there is no sign-up, watermark or daily limit. The video itself is not changed.
How the conversion works
An MP4 file is a container that holds a video track and one or more audio tracks, usually compressed with AAC. The tool asks your browser to decode the audio track, the same decoder that plays the video, into raw sound, and then compresses that sound again as MP3 with the LAME encoder, which runs in the page. No video frames are processed, so the conversion is quick: typically a few seconds for each minute of sound, depending on your device.
Because the sound is decoded in memory, the length is limited to 20 minutes and the file to 300 MB. Decoded stereo audio needs about 21 MB per minute, so a 20-minute video uses roughly 420 MB of memory while it is converted. For longer recordings, cut them into parts first.
Choosing a bit rate
- 64–96 kbps (mono or stereo): speech such as lectures, interviews and audiobooks. A one-hour talk at 64 kbps is only about 29 MB.
- 128 kbps: the usual choice for music; about 1 MB per minute.
- 192–256 kbps: high quality for music you care about; 1.4 to 1.9 MB per minute.
- 320 kbps: the maximum for MP3, about 2.4 MB per minute. Differences from 192 kbps are hard to hear on most equipment.
As a rule of thumb the file size in megabytes is the length in minutes multiplied by the bit rate in kbps divided by 133.
Worked example
You recorded a 12-minute lecture on your phone as a 180 MB MP4 and want to listen to the sound on the bus. Drop the file, choose 64 kbps and tick Mono. The tool decodes the audio, encodes it and gives you lecture.mp3: about 12 × 64 ÷ 133 ≈ 5.8 MB, a small fraction of the original, with speech that is perfectly clear. If you convert a music video with the same settings the result would sound thin, so use 192 kbps and stereo for music.
Troubleshooting and tips
- "Could not read the sound". The video may have no audio, or use a codec your browser does not support. Try Chrome or Edge, or re-export the video as MP4 with AAC audio.
- Very long videos. Cut them into parts shorter than 20 minutes first, or convert only the part you need.
- Copyright. Convert only videos you own or have permission to use. This tool does not download anything from the internet.
- Need to trim the audio? Convert first, then cut the MP3 with an audio cutter.
- Phones. Large files use a lot of memory; if the page stops responding, close other tabs or use a shorter clip.
Frequently asked questions
Is my video uploaded to a server?
No. The sound is read and converted to MP3 in your browser, on your own device. The video and the MP3 never leave it.
Which quality should I choose?
128 kbps is the standard for music and is fine for most uses. Choose 192–320 kbps for the best quality, and 64–96 kbps for speech such as lectures and podcasts, where files become much smaller. Mono is enough for speech.
Is there a limit on the length of the video?
Yes: files up to 300 MB and 20 minutes. The sound is decoded in memory on your device, which takes about 21 MB for each minute of stereo audio, so longer videos could make a phone or an older computer run out of memory.
Why does it say the sound could not be read?
The browser decodes the audio itself, so it works only for formats it understands. MP4 with AAC audio, the most common kind, works in all current browsers. A video without any sound, or with a rare audio codec, will fail; Chrome and Edge support the most.
Does the conversion lose quality?
The original sound is already compressed (usually AAC). Converting it to MP3 compresses it a second time, so a high setting such as 192 kbps or more keeps the result very close to the original. For the best quality, do not convert again and again.