Merge videos
Combine clips into a single video, in the order you choose. Done on this device, never uploaded.
- Nothing is uploaded
- Works offline after first visit
- Open source
- No watermark · limit is your device’s memory; phones hold less
Joins two or more videos (MP4, MOV, WebM, MKV) end to end into one MP4, in the order you set. 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.
How it works
- Drop two or more videos (MP4, MOV, WebM or MKV), or tap to pick them.
- Put them in order with the arrows. The first video sets the size of the result.
- Merge. The clips are joined and encoded into one MP4, with each clip’s sound in place.
In your browser, not on a server
Mediabunny (MPL-2.0) reads each MP4, MOV, WebM or MKV clip in your tab. Your browser decodes the frames (WebCodecs), draws them one clip after another onto a picture the size of the first clip, and encodes the whole once into an MP4, H.264 where available and VP9 or AV1 otherwise. Each clip’s sound is decoded by your browser and laid end to end to match.
Compared with upload-based tools: Online video mergers upload every clip before they start, cap free files at a few hundred megabytes, and often stamp a watermark on the result. Here the clips never leave 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
Are my videos uploaded?
No. Your browser decodes each clip, draws its frames one after another and encodes them into one MP4 in this tab. There is no upload and no watermark.
Can I join videos of different sizes or shapes?
Yes. The result takes the size of the first video, and any clip with a different shape is fitted inside it with black bars, so nothing is stretched or cut off. Put the clip whose shape you want first, or crop the others to match first with Crop video.
What happens to the sound?
Each clip keeps its own sound, lined up with its picture. A clip with no sound is silent in the result. Tick Remove the sound for a silent video.
Why does merging take a while?
Clips from different cameras rarely share the same format, so every frame is encoded again to make one continuous video. That runs on your device, using its hardware video encoder where the browser has one.
More video and audio tools
Add audio to video
Put music or a voice-over on a video, or replace its sound. The picture is copied as it is, and nothing is uploaded.
Reverse video
Make a clip play backwards, for a rewind effect, a boomerang or a laugh. Done on this device, never uploaded.
Video to JPG
Turn a video into still images: a few good frames or every single one. Done on this device, never uploaded.
Trim audio
Cut a song, a voice memo or a podcast down to the part you want, with fades if you like. Done on this device, never uploaded.
Popular conversions
Guides
- How to combine or merge videos into one on any deviceMost camera rolls can play clips one after another, not merge them into a single file. Here is what actually joins them.