# Add Music to Video

Drop a video and a song, set the volumes, save. The picture stays untouched.

URL: https://shortformkit.com/add-music-to-video/
Updated: 2026-10-13

The picture is copied without re-encoding, so quality stays exactly as it was. The new sound mix is encoded once. The song repeats if the video is longer and fades out at the end.

The conversion runs inside your browser with WebCodecs, the video engine built into modern browsers. That is why there is no upload, no queue and no file size limit set by us: only your device's memory limits it. Your file stays private.

Planning an export for a platform? Work out bitrate and size with the [file size calculator](https://shortformkit.com/video-file-size-calculator/), and check what Reels and TikTok cover with the [safe zone checker](https://shortformkit.com/safe-zone-checker/).

Converter engine: [Mediabunny](https://mediabunny.dev) (MPL-2.0) on WebCodecs. MP3 encoding: [LAME](https://lame.sourceforge.io) (LGPL).

## How it works

1. **Drop your file** Or tap to choose it. It is read on your device, nothing is uploaded.
2. **Pick the options** If the tool has any, for example quality or target size.
3. **Save the result** Click Convert, wait for 100 %, then Save file.

## FAQ

**Can I use any song?**
Only music you have the rights to. Platforms like YouTube, Instagram and TikTok mute or block videos with copyrighted songs. Their own music libraries are the safe choice.

**How do I replace the original sound?**
Set Original sound to 0 %. Only the music is left.

**Is my file uploaded?**
No. The file is processed in your browser and never sent to our server.

**Is there a file size limit?**
We don't set one. Very large files need enough free memory on your device; a computer handles more than a phone.

**Which browsers work?**
Chrome and Edge on computers and Android work best. Safari works in recent versions. If your browser lacks a codec, the tool tells you.

**Is it free?**
Yes. No account, no watermark, no daily limit.


Source: Shortform Kit (https://shortformkit.com/add-music-to-video/). Free, no login.