How to use the MP3 to MP4 tool
- Choose your MP3 or other audio file.
- Add a cover image and an optional title.
- Pick the video size (1280×720 is standard for YouTube).
- Press Create video and download the MP4.
About this tool
YouTube, Instagram and most social platforms accept video, not audio. Wrapping an MP3 in a video with a still cover image is the standard way to publish a song, a podcast episode or a voice recording, and a still image compresses to almost nothing, so the file stays small even for a long track.
Choose a cover image and an optional title. The still-image mode renders very few frames, so even an hour-long audio file converts quickly. If you want something more lively, the Audio Visualizer adds animated bars or a waveform.
Why use ToolsCrow for this
- Tiny files. A still image costs almost no bitrate.
- Any audio format. MP3, WAV, M4A, AAC, OGG and FLAC.
- Handles long files. Podcast-length audio works.
- Private. Nothing is uploaded.
Good to know
- Audio longer than one hour is refused, since the browser would need too much memory.
- The audio is re-encoded to AAC or Opus for the video container, which is a small quality change from the MP3 you started with.
Frequently asked questions
Is my video uploaded to a server?
No. Everything runs inside your browser tab using your own device's video hardware. Your file is never sent to ToolsCrow or anyone else, which also means there is no waiting for an upload and it keeps working if your connection drops after the page has loaded.
Is it really free? Is there a watermark?
It is free with no sign-up, no watermark and no daily limits. The only limits are the ones your device sets: memory and processing power.
How large a video can I use?
Because the video is processed on your device, the limit is your device's memory rather than a server quota. Phone clips of several hundred MB are fine on most devices, and desktop computers usually handle 1 to 2 GB. Files over about 4 GB are not supported.
Which browsers work best?
Current Chrome, Edge and Safari (16.4 or newer, including iPhone and iPad) work best because they include the WebCodecs video engine. Recent Firefox versions work for many files. Older browsers fall back to a much slower real-time mode or may not work at all.
What image size should I use for YouTube?
1280×720 or 1920×1080 with a 16:9 cover image. The cover is fitted to the frame, and a blurred version fills any gaps.
Can I add animated bars instead of a still image?
Yes, use the Audio Visualizer tool, which draws music bars or a waveform over your cover.
Will the audio quality change?
It is re-encoded once into the video, which is a small, usually inaudible change at the bitrates used here.
Related video tools
- Audio VisualizerMake a video that moves with your music: animated bars or a waveform over your cover image, in your own colours.
- Video to MP3Turn a video into an MP3 in one step.
- Photo Slideshow MakerTurn a set of photos into a video with music, crossfades and a gentle zoom.
- Add Text to VideoAdd a title, caption or meme text to any video.
- Video CompressorShrink any video to a fraction of its size while keeping it sharp, or type the exact size you need in MB.
- Extract Audio from VideoPull the soundtrack out of a video and save it as an MP3, M4A, AAC or WAV file.
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