Convert MP4 to MP3 Online
Turn MP4 files into MP3 directly in your browser using ConverterUp. There is no upload, no waiting in a queue, and no account required — your files stay on your device while WebAssembly does the work locally. Adjust quality and dimensions where supported, then download the result. The output keeps the visual fidelity you'd expect from a desktop app while running entirely in the browser tab.
Convert MP4 to MP3 nowHow to convert MP4 to MP3
Open the converter
Click the button to open the MP4 to MP3 tool. It loads instantly — no install, no signup.
Drop your MP4 file
Drag your MP4 file into the upload area or click to browse. The file stays in your browser memory only.
Download MP3
The conversion runs locally and finishes in seconds. Click download to save the MP3 file to your device.
MP4 vs MP3 at a glance
Key technical differences between the two formats, so you know what to expect before converting.
| Feature | MP4 | MP3 |
|---|---|---|
| Type | Video container | Audio file |
| Compression | Lossy | Lossy |
| Audio track | Yes | Yes |
| Common codecs | H.264, H.265, AV1, AAC | — |
| Browser support | All browsers | All browsers |
| Extensions | .mp4 | .mp3 |
| MIME type | video/mp4 | audio/mpeg |
| Introduced | 2003 · MPEG (ISO/IEC 14496-14) | 1993 · Fraunhofer IIS / MPEG |
What changes when you convert MP4 to MP3
- MP3 is audio only: the video track is discarded and only the soundtrack of the MP4 file is kept.
- The audio is encoded as MP3 with variable bitrate (LAME V2, about 170–210 kbps) — transparent for most listeners.
- The MP3 file is a small fraction of the video's size: a 3-minute track is typically around 4 MB.
- MP3 plays on every phone, computer, car stereo and music player, and every audio editor imports it.
- Conversion can't improve the sound: the MP3 file is at most as good as the audio inside the MP4 file.
About MP4
MP4 (MPEG-4 Part 14) is the most widely supported video container. It typically holds H.264 or H.265 video with AAC audio and plays on virtually every phone, browser, TV and editor.
- Best for
- Sharing videos, uploading to social networks and YouTube, and playback on any device.
- Strengths
- Universal playback, good compression, streaming-friendly.
- Limitations
- Lossy codecs, so repeated re-encoding gradually reduces quality.
About MP3
MP3 (MPEG-1 Audio Layer III) is the most widely compatible compressed audio format. It removes sounds the ear barely perceives to shrink files to about a tenth of CD size.
- Best for
- Music, podcasts, audiobooks, voice notes and ringtones.
- Strengths
- Plays literally everywhere; small files; good quality at 160–320 kbps.
- Limitations
- Lossy; slightly less efficient than AAC or Opus at low bitrates.
Frequently asked questions
Is the MP4 to MP3 conversion really free?
Yes. ConverterUp is fully free, with no signup, no watermarks, and no daily quota for the MP4 to MP3 converter. We support the project through unobtrusive ads.
Are my MP4 files uploaded to a server?
No. Conversion runs in your browser using WebAssembly. The MP4 bytes never leave your device, and we have no upload endpoint at all.
What is the maximum file size?
For MP4 input, the soft cap is 50 MB for images and 500 MB for video. Practical performance depends on your device's RAM.
Does converting MP4 to MP3 lose audio quality?
Slightly, in theory: MP3 is lossy and the soundtrack of most videos is already compressed (usually AAC). At the variable bitrate used here (about 190 kbps) the difference is inaudible for most people. Choose WAV if you need a lossless copy for editing.
Can I convert MP4 to MP3 from a YouTube or TikTok link?
No. ConverterUp converts files that are already on your device and never downloads from YouTube, TikTok or other sites. Save the video first (only content you have the rights to), then drop the file here.
Is there a file size limit for converting MP4 to MP3?
Videos up to 500 MB are supported. Everything runs in your browser, so large files depend on your device's memory, and nothing is uploaded or queued.
Related guide
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