Why does my joined video have black bars?

One of the clips is a different shape from the first one and has been fitted inside the frame rather than stretched or cropped. Reordering so that a clip of the shape you want comes first changes the frame.

Can I reorder the clips before merging?

Remove them and add them again in the order you want. The list order is the film order.

Why does it take so long?

Because the clips have to be made compatible before they can be joined, which means decoding and re-encoding all of them. Expect roughly the running time of the footage.

Can I add a fade between clips?

Not here. The joins are straight cuts. A crossfade needs a timeline editor, which this deliberately is not.

Merge Videos

Join several clips end to end, in the order you choose.

Everything runs inside your browser. Your files never leave your device.

Drop your files here

.mp4, .m4v, .mov, .qt, .webm, .mkv, .ts, .mts, .m2ts · they stay on this device

Ask about Merge Videos

Questions about what this tool does, which option to pick, or what it can and cannot handle.

This is the one part of the site that uses a server. The question you type here is sent to an AI provider to be answered — your files and whatever you put in the tool above are not, and the assistant cannot see them. Answers are generated and can be wrong; the tool itself is not guessing.

About the Merge Videos

Merging clips end to end is the most basic act of editing there is, and it is the one that most often sends people looking for software far heavier than the job deserves.

Clips are merged in the order they appear in the list, which is the order you added them. Everything is redrawn at the first clip's dimensions, and this is the part worth understanding before you start, because it decides how the result looks. Whichever video you put first sets the frame for all of them. If clip one is landscape and clip two was filmed on a phone held upright, the portrait footage is fitted inside the landscape frame with black at the sides. It is not stretched and nothing is cropped away — the shape of every clip is preserved. If you would rather the whole film were portrait, put a portrait clip first.

Sound is handled to match. Each clip contributes exactly as much audio as it has picture, and a clip with no sound at all contributes silence of precisely the right length. That sounds obvious and is the thing cheap joiners get wrong: without it, one silent clip in the middle pulls every subsequent second of audio forward and the rest of the film drifts out of sync with its own soundtrack.

Because every clip has to be brought to a common size and a common codec, everything is decoded and encoded again. Joining four clips therefore takes roughly as long as watching them. There is no shortcut that avoids this when the sources differ, and sources almost always differ.

How to use it

1Add all the clips. They are joined in the order listed, so add them in the order you want them.
2Put the clip whose shape you want the finished film to have at the top.
3Choose a container and a quality.
4Join them, then download the single file.

Questions

Why does my joined video have black bars?: One of the clips is a different shape from the first one and has been fitted inside the frame rather than stretched or cropped. Reordering so that a clip of the shape you want comes first changes the frame.
Can I reorder the clips before merging?: Remove them and add them again in the order you want. The list order is the film order.
Why does it take so long?: Because the clips have to be made compatible before they can be joined, which means decoding and re-encoding all of them. Expect roughly the running time of the footage.
Can I add a fade between clips?: Not here. The joins are straight cuts. A crossfade needs a timeline editor, which this deliberately is not.