ToolGPT

Merge video clips into one file

Attach two or more clips and ask ToolGPT to join them. They are combined in the order you choose, matched to one frame size and frame rate, and saved as a single video in your browser.

  • Runs in your browser
  • No sign-in needed
Drop or choose your filesThe assistant opens with your files and does the rest.Choose Files
Things you can type
intro.mp4 · beach-day.mov
Open ToolGPTAttach a file and describe what you need.

What it can do

  • Your order

    Clips play in the order you attached them, unless you name a different order.

  • Mixed sizes and frame rates

    Every clip is fitted into one shared frame and frame rate, so footage from different phones and cameras joins cleanly.

  • Sound stays in sync

    A clip with no sound gets silence of the same length, so the clips after it keep their audio in step.

  • Results and uploads together

    Merge something ToolGPT just made, such as a trimmed clip, with a file you attached.

  • Four output formats

    The merged video is an MP4 by default, or a MOV, WEBM or MKV if you ask.

How it works

  1. 1

    Attach the clips

    Add two or more videos with the + button, in the order you want them if you can.

  2. 2

    Ask to merge

    Say “merge these”, and name a different order or format if you need one.

  3. 3

    Download the video

    The merged file appears as one result card with a download button. Your clips are not changed.

How clips of different sizes are joined

Phone clips are often vertical, camera clips are wide, and screen recordings can be any size. ToolGPT makes the merged video as wide as the widest clip and as tall as the tallest one. Each clip is scaled to fit inside that frame, and any space around it is filled with black, so nothing is stretched or cropped.

The frame rate is the highest one among your clips, up to 60 frames per second. Clips can also be in different formats, for example an MOV from a phone and an MP4 from a camera.

What merging involves

Merging always re-encodes, because the clips must share one frame size, frame rate and codec. MP4, MOV and MKV results use H.264 video with AAC sound, and WEBM uses VP8 with Opus. A WebAssembly build of FFmpeg does the work in your browser, so a long merge takes a while on a slower device. The progress bar follows the full combined length.

Every clip is loaded into the page's memory, so keep the clips together well under about 2 GB.

What merging does not do

It joins video clips one after another, without transitions. It cannot merge an audio-only file into a video or turn photos into a video; ToolGPT has separate tools for adding music under a video and for making a slideshow.

Frequently asked questions

How many clips can I merge?

At least two. There is no fixed maximum, but every clip is processed in your browser, so very large sets take longer and need more memory.

Can I trim a clip before merging it?

Yes. Ask ToolGPT to trim the clip first, then to merge the trimmed result with the others.

Are my videos uploaded?

No. The clips are merged in your browser.

Try it with your own file

Open ToolGPT, attach a file, and type what you want done.

Open ToolGPT

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