MP3 to MP4 converter
Turn MP3 audio into an MP4 video with your own picture or a plain colour, free. No upload, no sign-up, no watermark: it runs in your browser.
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Quick answer: To turn MP3 audio into MP4 video, add the MP3 file to the iHateFiles MP3 to MP4 converter, choose a picture if you want one, and press the button. The conversion runs in your browser, so the file is never uploaded, and it is free with no sign-up, watermark or size limit. A video needs something to show, so one picture of your choosing, or a plain colour, stays on screen for the whole MP3.
Getting an MP3 onto a site that only takes video
YouTube and most social sites have nowhere to put a sound file, so a song, a podcast episode or a voice recording has to become a video first. An MP4 with one picture on screen is all that takes: cover art for a track, a logo for a show.
Choose the picture before you start, because it sets the shape of the video unless you pick one. Square art makes a square video, which sits well in a feed and gets black bars on YouTube. For YouTube choose 16:9 and either fill the frame or let the bars show.
Should you convert MP3 to MP4?
Worth doing when something only accepts video, such as YouTube or a social post. If you just need to send or play the sound, keep the MP3. The MP4 sounds no better and shows one still picture for its whole length.
What happens to the MP3 sound
MP3 sound is encoded to AAC on the way in, at the bitrate you choose, 192 kbps unless you change it. An MP4 can hold an MP3 track, but support for that is patchy, and AAC is what players expect.
Where the MP4 picture comes from
From you. Choose a photo, cover art or a logo and it stays on screen for the length of the MP3; choose nothing and the screen is a plain colour. The shape can follow the picture or be set to widescreen, square or vertical, and a picture that does not fit either gets coloured bars or is cropped to fill. Most image formats work, HEIC photos included.
Why the MP4 is not much bigger than the sound
A picture that never changes takes almost no space as video, roughly 16 kbps plus a little for each repeat of the full picture. Nearly all of the MP4 is the sound itself, and a long recording does not cost a long video encode: the picture is prepared once.
MP3 and MP4 side by side
| MP3 | MP4 | |
|---|---|---|
| Inside the file | MPEG-1 Layer III | H.264 video with AAC sound |
| Compression | Lossy | Lossy |
| Carries sound | Yes | Yes |
| Shows a picture | No | Yes |
| Plays on | everything, including car stereos and hardware twenty years old | every phone, laptop, TV, browser and messaging app |
| Here | Read and write | Read and write |
What usually goes wrong
About the MP3. Converting an MP3 to another lossy format compounds the damage, because the second encoder is guessing at audio the first one already threw away.
About the MP4. Two MP4 files can behave completely differently depending on the codecs inside. A file that will not play is usually an unusual codec in an ordinary container, not a broken file.
How to convert MP3 to MP4
- Add your MP3 file. It is read from your disk and stays there.
- Choose a picture to show, or leave it on a plain colour.
- Press convert and the MP4 file is saved back to your device.
MP4 converter: everything that converts to MP4
Questions
How do I convert MP3 to MP4?
Open this page, add your MP3 file, choose a picture if you want one, and press the button. Your browser builds the video and saves it to your device. Nothing is uploaded.
Is this MP3 to MP4 converter free?
Yes, completely. There is no account, no sign-in, no watermark and no daily limit, because there is no server doing the work. Your own device does it.
Are my files uploaded anywhere?
No. There is no upload endpoint. The conversion runs inside this browser tab, so your file never leaves your device. You can open your browser's network panel and watch: nothing carrying your file is sent.
Is there a file size limit?
No fixed limit. Because the work happens on your machine there is no server quota. The only ceiling is your own device's memory, which for video means very large files may be slow.
Do I have to add a picture?
No. Without one the video shows a plain colour, black unless you choose another, with your MP3 playing over it.
Does the sound lose quality?
A little, in theory. MP3 is encoded again as AAC, because support for an MP3 track inside an MP4 is patchy. At the default 192 kbps that is very hard to hear; choose 256 or 320 kbps for music you care about.
Can it make a waveform or lyric video?
No. One picture stays on screen for the whole of the MP3 and nothing moves.
Will the MP4 work on YouTube?
It is an ordinary MP4: H.264 picture at 30 frames a second with AAC sound, which is what video sites ask for. Choose the shape that suits the site. Each one sets its own limits on length and file size.
Can I convert several MP3 files at once?
Yes. Add as many as you like and they are converted one after another, then offered as a single ZIP. They all use the same picture.