Combine several videos into one
Add your clips, put them in order and get a single MP4 video, even if their sizes differ. Everything happens in your browser: no video is uploaded.
- Free
- MP4 export
- 720p or 1080p
- 100% private
100% private — Everything is processed directly in your browser: your files, voice, and image are never sent to Chatzam's servers.
How do you merge videos?
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Add your videos
Import several MP4, MOV, WebM… files from your computer or your phone.
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Set the order and format
Move each clip up or down, remove the ones you don't need, then choose the size: the same as the first video, 720p or 1080p, in landscape or portrait.
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Download the video
Start the merge and get a single MP4 file that plays all your clips in the order you chose.
Clips joined end to end, hassle-free
Mixed formats welcome
MP4, MOV, WebM… Clips from different sources are re-encoded together into a single MP4 (H.264 for video, AAC for audio).
No distortion
If the sizes differ, each clip is scaled and padded with black bars: nothing is stretched or squashed.
Continuous sound
A clip with no audio track gets silence of the same length, so the final video keeps a soundtrack from start to finish.
Confidential
The merge is done in your browser by FFmpeg: your family or work videos are never uploaded.
Joining videos end to end: how it works
Clips are played one after another in the order of the list: the first one in the list opens the video, the last one ends it. To change the order, move a clip up or down; to drop one, remove it from the list. Since your files may come from different devices, say an iPhone in MOV and an Android phone in MP4, they are all re-encoded into the same format: MP4 with H.264 video and AAC audio. That's the most compatible combination, played by phones, computers and TVs, and accepted by social networks and messaging apps. A silent clip gets silence added, so the sound stays continuous.
Vertical and horizontal videos: what the black bars do
Choose the output size based on where the video will go: 1080p landscape (1920 × 1080) for YouTube or a TV, 1080p portrait (1080 × 1920) for a Story or TikTok, 720p (1280 × 720 or 720 × 1280) for a lighter file. The "Same as 1st video" option keeps the resolution of your clips if they all come from the same phone. When a clip doesn't have the same proportions, it's scaled down to fit entirely in the frame, then centered between black bars. Example: a vertical 1080 × 1920 video placed in a 1920 × 1080 frame keeps 1,080 pixels of height, so about 608 pixels of width, with a black bar on each side.
Processing time and good practice
The editing is done by your device, without a server: it's slower than installed software, especially on a phone, and every minute of video has to be re-encoded. The tool is therefore designed for short clips, a few minutes in total. To go faster, first cut out the parts you don't need with "Cut / Trim Video", and choose 720p if high definition isn't essential. If the final file is too big for an email or a messaging app, run it through "Compress Video" afterwards. And if a clip was filmed the wrong way round, straighten it first with "Rotate Video".
Frequently Asked Questions
How can I join videos together for free?
Add your clips, put them in the order you want with the up and down buttons, choose the output size and start the merge. You download a single MP4 video, for free and with no sign-up.
Can I merge videos in different formats, like MOV and MP4?
Yes. MP4, MOV, WebM and other common formats can be mixed: all clips are re-encoded into a single MP4 (H.264 + AAC).
How do I combine a vertical video and a horizontal video?
Choose the final format, landscape or portrait. The clip that doesn't have the same proportions is scaled down and centered with black bars, without being distorted or cropped.
Why does merging take a while?
All the videos are re-encoded by your device, directly in the browser. The time depends on the total length, the resolution you choose and how powerful your device is: for long videos, choose 720p or shorten the clips.
Are my videos sent to a server?
No. Processing happens entirely in your browser: your files never leave your device. It's free and no account is needed.