How to use
- Drag in or select two or more video files to combine.
- Click Merge Videos to join the clips end-to-end into one MP4.
- Wait while the videos are processed and re-encoded in your browser.
- Download your merged MP4 file.
Frequently asked questions
Will my videos be uploaded to a server?
No. All processing happens locally in your browser with ffmpeg.wasm, so your videos never leave your device and nothing is uploaded.
What video formats can I merge?
You can add common video files such as MP4, MOV, WebM, and other formats your browser can read. The clips are combined and the result is always saved as a single MP4.
Can I merge clips with different sizes, resolutions, or codecs?
Yes. The clips are re-encoded while merging, so videos with different resolutions, aspect ratios, or codecs are joined cleanly into one MP4.
Why is the first run slow?
On first use the tool downloads the ~30 MB ffmpeg engine. It is then cached in your browser, so later merges start much faster.
How many videos can I merge at once, and are there size limits?
You can add as many videos as you like. There is no fixed limit, but very large or numerous files take longer and use more memory, since everything runs in the browser.
What happens if a clip has no audio?
The merger first tries to combine video and audio together. If one of the clips is silent, it automatically retries with a video-only merge so your files still join into one MP4.
About this tool
Free online video merger to join and combine multiple video clips into one MP4. Works 100% in your browser with no uploads — merge videos privately and securely.