Video Merger (Merge Videos)

Put several clips together into one video: holiday shots, parts of a recording that were split, or a series of short clips for social media. When all clips come from the same camera or app (same codec, size and frame rate), they are joined without re-encoding — instantly and without quality loss. Mixed clips are fitted into one frame size, set to the same frame rate and re-encoded, and you can add crossfades or other transitions. Everything happens in your browser.

How to use this tool

1. Choose the clips in the order they should play, or sort them by file name.
2. Pick the output size: the first clip's size, landscape 1080p or 720p, vertical 1080 × 1920 or square.
3. Choose whether clips of a different shape get black bars or are cropped to fill.
4. Optionally choose a transition and its length, then press Calculate and download the joined video.

Formula

Total length = sum of clip lengths − (number of clips − 1) × transition length

A transition overlaps the end of one clip with the start of the next, so each one shortens the video by its length. Clips without sound get silence so the audio stays in step. Joined-without-re-encoding output keeps the original format; otherwise the result is H.264 + AAC MP4 at 30 fps.

Example

Three clips of 12 s, 20 s and 8 s with 1-second crossfades give 40 − 2 × 1 = 38 seconds. Without transitions the result is exactly 40 seconds, and if all three came from the same phone it is joined in a second or two.