A trip filmed in twenty short clips, a presentation recorded in parts, three takes of a product demo that belong together: often the simplest way to share them is as one continuous video. Sending a single file is easier for the recipient and plays without gaps between clips.
Add two or more videos, drag them into the right order, pick an output size and format, and press Convert. The tool fits every clip into one common frame, joins them one after another with their sound, and gives you a single MP4 or WebM. Nothing is uploaded; the joining happens in your browser.
Why merged clips are re-encoded
Two video files can only be glued together without re-encoding when they match exactly: the same codec, resolution, frame rate and audio format. Clips from different sources almost never do. A phone records 1080p at 30 fps in portrait, a screen recorder writes 1440p WebM at a variable rate, and an older camera produces 720p AVI. Joining them naively produces glitches, a frozen picture or sound that drifts out of sync.
So this tool re-encodes every clip to shared settings before joining them. Each clip is scaled to fit the output frame without being stretched; when its shape differs, the remaining space is filled with black bars, at the sides for a portrait clip in a landscape frame and above and below in the opposite case. All clips are brought to the frame rate of the first one and their sound to 48 kHz stereo. A clip without sound gets silence of its own length, so the audio of the clips after it stays in sync.
When to merge videos
Holiday and event clips
Phones split long days into dozens of short videos. Merging the best ones in order gives you a single file to send to family or keep as a summary.
Lessons and presentations recorded in parts
If a screen recording stopped halfway, or each section was recorded separately, joining the parts produces one video that viewers can watch from start to finish.
Intro and outro around a main clip
Add a short title clip before your video and a closing card after it. Put them in the queue in that order and they are joined in sequence.
Order, size and format options
Files are joined in the order shown in the queue, which is numbered once there are two or more. Drag a file by its handle, or use the keyboard, to move it. Size decides the output frame. Same as the first video uses the first clip's dimensions and shape, brought down to 1920 pixels on the long side if it is larger, so 4K footage comes out as 1080p. The 1080p, 720p and 480p presets set the short side while keeping the first clip's shape, which makes the first clip the reference for portrait or landscape.
Output format offers MP4, with H.264 video and AAC sound, and WebM, with VP8 and Vorbis; MP4 is the default and plays almost everywhere. The result is named after the first clip with -merged added. Merging is done by ffmpeg built for WebAssembly, which downloads once (about 31 MB) and runs on a single thread, so joining long clips takes roughly as long as converting all of them. Each input may be up to 500 MB, but the total is limited by your device's memory, so keep big merges to a desktop browser.
How to use this tool
- Drop two or more MP4, MOV, WebM, MKV or AVI files on the box above, or click it to choose them. Add more at any time with Add more files.
- Drag the files into the order they should play.
- Choose a Size (Same as the first video, 1080p, 720p or 480p) and an Output format (MP4 or WebM).
- Press Convert and download the single merged video when it is ready.
Limitations
- Clips are joined with a hard cut. There are no transitions, fades or titles.
- Every clip is re-encoded, so merging takes time and costs a little quality even when the clips already match.
- Clips of a different shape from the first get black bars rather than being cropped or zoomed. Crop or resize them first if you want them to fill the frame.
- If one file cannot be read, that file is marked as failed and the others go back to the queue so you can merge them without it.