Video Merger – Merge Videos Online

How to use the Video Merger

1. 1. Upload two or more videos. Files stay on your device.
2. 2. Arrange them in the desired order with move buttons or drag and drop.
3. 3. Select the output format (MP4 or WebM).
4. 4. Click Merge Videos. Processing runs locally in this tab.
5. 5. Preview the result if you want, then download it.

Can I merge different video formats?

Yes, when the in-browser engine can decode each file. Supported containers include MP4, WebM, MOV, MKV, AVI, MPEG, and OGV. Mixed codecs and resolutions are normalized during merge. If a file uses a codec the engine cannot decode, you will see a clear error instead of a broken download.

Does merging reduce video quality?

Sometimes. Compatible clips may be concatenated without a full re-encode. Different resolutions, frame rates, or codecs are re-encoded so the output is one playable file. That can change quality. We do not advertise lossless merging.

Are my videos uploaded?

No. Processing stays in this tab. Your videos are not sent to Toolshelf servers. Keep the tab open while merging, especially for larger files.

What this tool includes

• Merge MP4, WebM, MOV, MKV, AVI, MPEG, and OGV in the browser
• Upload multiple videos and add more later
• Reorder clips with buttons, keyboard, or drag and drop
• Preview each video before merging
• Normalize mixed resolutions and frame rates without stretching
• Export MP4 or WebM and download locally
• No signup — videos are not uploaded

Frequently asked questions

How do I merge two videos?

Upload at least two videos, put them in the order you want, choose MP4 or WebM, click Merge Videos, then preview and download the combined file.

Can I merge MP4 files?

Yes. MP4 is supported for both input and output. You can also mix MP4 with WebM, MOV, and other formats this tool can decode.

Can I merge videos with different resolutions?

Yes. The merger uses the first video’s resolution as the output size. Other clips are scaled to fit and letterboxed if the aspect ratio differs, so footage is not stretched.

Can I merge videos with different formats?

Yes when the browser engine can decode them. Clips are not glued together as raw bytes. They are decoded, normalized, concatenated in list order, then encoded to MP4 or WebM.

Is the Video Merger free?

Yes. Toolshelf Video Merger is free to use in your browser. No account is required.

Are videos uploaded to a server?

No. Files are read with the browser File API and processed locally with a WebAssembly media engine in this tab. Video is not uploaded to Toolshelf servers. The current queue and last merge can stay in this browser until you click Start Over. Analytics, when enabled, only records anonymous events such as “merge completed” — not filenames or video contents.

Can I merge videos on mobile?

Yes. The upload area, file list, move up/down controls, and Merge Videos button are designed for touch. Drag-and-drop reordering also works where the browser supports it; the buttons always work.

How many videos can I merge?

You can queue up to 10 videos, as long as each file is at most 200 MB and the combined size stays within 400 MB. Browser memory still varies, so very large clips may fail even within those limits.

Does merging reduce quality?

Matching clips may be concatenated with a stream copy when that produces a valid file. Mixed resolutions, frame rates, or codecs are re-encoded so the result plays reliably. That can change quality compared with the originals. We do not claim lossless merging.

Related tools

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