Convert MP3 to MP4
An MP3 is sound only; this makes it a video by adding a picture, so YouTube, Instagram and TikTok accept it.
- Nothing is uploaded
- Works offline after first visit
- Open source
- No watermark · limit is your device’s memory; phones hold less
Convert an MP3 to an MP4 video with a cover picture, for YouTube or social apps that only take video. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The size limit is your device’s memory, and phones hold less; give the page a short while after one visit to save itself for offline use, and then it works offline.
Done
Open the network tab. Your files never appear in it.
Add files and run the tool to see every request this tab makes.
Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.
MP3 and MP4 are different kinds of file: an MP3 holds only sound, and an MP4 is a video. Sites that “convert MP3 to MP4” are adding a picture track, because video sites and most social apps refuse sound-only uploads.
This page does that honestly: drop the MP3 with an album cover, photo or logo, pick the shape for where it is going, and the MP4 is written in your browser with the picture held for the whole song. Without a picture, the video shows the song’s title.
If you have an MP4 video and want its sound as an MP3, that is the other direction: use Video to MP3.
How it works
- Drop the MP3 and a picture, or tap to pick them. Drop several MP3s to make a video of each.
- Choose 16:9 for YouTube, square for feeds, or 9:16 for Shorts, Reels and TikTok.
- Convert, and upload the MP4 wherever you need it.
In your browser, not on a server
Your browser decodes the sound into plain samples, draws the picture once onto a canvas (fitted whole over a blurred copy, or the title on a plain colour), and its own WebCodecs encoders write that still frame once a second with the sound as AAC or Opus. Mediabunny (MPL-2.0) packs them into an MP4.
Compared with upload-based tools: Online MP3-to-video converters upload your music and cover art, add their logo to free videos, and cap the length. Unreleased tracks and private recordings stay private here: nothing leaves your device.
Verify it yourself. Give the page a short while after one visit to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.
Questions
Does converting lower the sound quality?
Slightly: the sound is re-encoded as AAC (or Opus) with a target of up to 192 kbps, which is as good as a typical MP3 to the ear. Simple audio can come out lower, because the encoder spends fewer bits where it does not need them. Video sites re-encode uploads anyway.
Can I use a moving background or a waveform?
Not on this page: it makes a still-picture video, which is what most music uploads on YouTube are. For moving pictures, merge real video clips with Add audio to video.
I want the MP3 from an MP4, not the other way round.
Use Video to MP3, which pulls the sound out of a video as an MP3.
Is the file uploaded anywhere?
No. There is no server in this process. The page is a static file and the work is done by code running inside your browser tab. Give the page a short while after one visit to save itself for offline use; then you can turn off Wi-Fi and it still works.
More video and audio tools
Audio to video
Put a song, a podcast episode or a voice note on a still picture, ready for YouTube or social apps. Made on this device.
BPM and key finder
Drop an audio file and read its tempo, key and Camelot code. The song is analysed on this device.
Online tuner
Play a note and see how sharp or flat it is. Guitar, bass, ukulele, violin or chromatic, with the sound kept in your tab.
Metronome
A steady click at any tempo, with the bar, the subdivisions and tap tempo, running on your device.
Other conversions
Guides
- How to turn audio into a videoTo put a song, a podcast episode or a voice note on YouTube, you need a video. Here is how to make one from the sound and a single picture.