The short answer
Drop two or more video clips on the tool below. Put them in order by dragging them, with the up and down arrow buttons, or with Sort by name. Press Merge videos; when it is done, the result appears with its length and a Download button.
If all clips match, the result line says No quality loss and the clips were simply placed one after the other. If they differ, it says Re-encoded together with the size of the result. Everything happens on your device, so nothing is uploaded and no watermark is added.
Try it here: Merge Videos
Open the full tool pageWhen merging is fast and lossless
A video file holds compressed picture and sound data plus settings that describe them: the container (MP4, MOV, WebM, MKV), the codec and its settings, the picture size and the sound settings. When all clips share the same container, the same codec settings, the same size and the same sound settings, their data can be copied one after the other without decoding and encoding anything again. The tool checks this for you.
This is usually the case for clips recorded with the same phone or camera in the same mode, for a long recording that the camera split into several files, and for pieces cut out of one video with a video trimmer. Even long clips are joined in seconds, and the quality is exactly that of the originals.
When the clips differ
Clips often differ: a vertical phone video and a horizontal screen recording, a 4K clip and a Full HD clip, an MP4 and a MOV, or a clip with sound and one without. Then every frame is drawn into one common frame and encoded again. Size when clips differ decides the size of that frame. Like the first clip uses the size of the clip at the top of the list; Like the largest clip uses the biggest one. Clips of another shape are placed in the middle with black bars and never stretched.
The result is an MP4 with H.264 picture and AAC sound, which plays on phones, Windows, Mac and TVs. Firefox cannot create AAC sound, so in Firefox the result is a WebM. Clips without sound stay silent for their whole length, so the sound of the other clips stays in sync with their pictures.
| Clips | What happens | Result | Quality |
|---|---|---|---|
| Same phone or camera, same mode | Joined without re-encoding | Same format as the clips | Identical |
| Parts of one recording or one trimmed video | Joined without re-encoding | Same format as the clips | Identical |
| Different sizes or orientation | Fitted with black bars, re-encoded | MP4 (WebM in Firefox) | Very close |
| Different formats, such as MP4 and MOV | Re-encoded | MP4 (WebM in Firefox) | Very close |
| Some clips without sound | Re-encoded, silence for those clips | MP4 (WebM in Firefox) | Very close |
Choosing the size and the order
Like the first clip is useful when the first clip sets the look of the whole video, for example a vertical intro followed by other vertical clips. Like the largest clip keeps the sharpest picture when you mix resolutions, at the cost of a larger file. If most clips are vertical and one is horizontal, put a vertical clip first and choose Like the first clip; the horizontal one then gets black bars above and below.
The order in the list is the order in the video. Phone files are often named by date and time, so Sort by name puts them in recording order with one click. You need at least two clips, and there is no fixed upper limit; the total length is limited by the memory of your device.
- Drag a clip up or down to move it
- Use the arrow buttons to move one step at a time
- Press Sort by name for files named by date
- Press Add more to add clips, or the × button to remove one
Built in options on phones and computers
Many phones can combine clips in their own video or movie editors, and Windows has Clipchamp, where you put clips on a timeline and export them. On a Mac, iMovie can do the same. These apps usually re-encode everything, even when the clips match, and exporting can take as long as with any re-encoding.
The browser tool is handy when you only want to join clips without editing, when you want a lossless result for clips from the same camera, or when you are on a computer without a video editor.
Common problems and fixes
- The result says Re-encoded although the clips come from the same phone: one clip was probably recorded in a different mode or size, or saved again by another app. The result is still good, it just takes longer.
- Black bars appear: the clips have different shapes. Make them the same shape first with a video crop tool, or put the clip whose shape you want first and choose Like the first clip.
- There is a silent gap: that clip has no sound. The silence keeps the other clips in sync; add music afterwards if you like.
- Your browser cannot read the video inside one of these files: some codecs, such as HEVC from iPhones, cannot be decoded in every browser. Try Chrome, Edge or Safari, or convert that clip to MP4 first.
- One clip is too long to process in the browser: use shorter clips, or trim the long one before joining.
- Merging takes long: re-encoding takes roughly as long as the clips play, less on fast computers. Keep the tab open until it finishes.