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Merge Videos

Join several clips into one continuous video, in the order you arrange them. Some detail is discarded to fit the target format; how much depends on the format and your settings.

Not uploaded to any serverConverted on this deviceGone when you close the tabHow this works

Drop your files here

MP4, MOV, MKV, WebM and 1 more formats · up to 512 MB each

or paste files from your clipboard

Ready when you are

Join several clips into one continuous video, in the order you arrange them. Everything happens in this tab; nothing is sent anywhere.

⌘K to search converters

How to use it

1
Add your files
Merge Videos works with MP4, MOV, MKV, WebM and AVI. Drop them in, browse for them, or paste from your clipboard.
2
Put them in the right order
The files are processed top to bottom. Drag them to rearrange before you start.
3
Run it and download
Press the button and save the result. Everything happens on your device, and nothing is uploaded.

Privacy, in plain words

Is it safe? Your video file is not uploaded anywhere

What “uploaded” normally means. On most online converters, pressing the button copies your file across the internet onto a computer owned by that website. That copy is what the word “upload” means, and it is the part nobody explains.

What happens instead. This site does not do it. There is no server here that receives files, so your video file is read, converted and handed back by the browser you are using right now. It never travels — so there is no copy to store, read, leak or hand over.

Check it yourself in ten seconds

Turn off your Wi-Fi after this page has loaded, then convert a file anyway. It still works, because everything needed is already on your device.

The longer explanation of how this works, and the full detail of what is and is not stored on the privacy page.

Why this matters more than it sounds

Video is the format where the thing being converted is usually a recording of people, and often of people who did not expect a third party to have a copy. It matters more than it sounds, because of what video files usually are:

Security-camera footage

your home or premises, and who was in it

Family videos

children, addresses, the inside of your house

Medical or therapy consultations

clinical recordings under strict handling rules

Unreleased footage

material under embargo or still being edited

A file that is never sent cannot be kept, leaked, subpoenaed or used to train anything. That is a property of how this works, not a promise about how carefully it is run.

How Merge Videos works

Join several clips into one continuous video, in the order you arrange them. Everything happens inside this page: the file is read from your device into memory, processed there, and handed back as a download. It is never sent anywhere, and closing the tab discards it.

What it accepts: MP4, MOV, MKV, WebM, AVI. Files are identified by their contents rather than their name, so a mislabelled file is still handled correctly.
What you get back: A MP4 file, downloaded straight to your device.
What happens to the data: The result is re-encoded, so some detail is discarded permanently. Starting from the original rather than from an already-processed file keeps that loss to one pass.
Size limit: Up to 512 MB per file. Because the work happens on your own machine, available memory is the real constraint — a laptop handles far more than a phone.

The settings, and what each one changes

Merge Videos exposes 8 settings. The defaults are chosen to suit the common case, so changing nothing is a reasonable way to start.

Target: Free text, used exactly as you type it.
Resolution: Choose between Keep original, 4K — 2160p, QHD — 1440p, Full HD — 1080p and others.
Frame rate: Choose between Keep original, 60 fps, 30 fps, 24 fps and others.
CRF: Constant Rate Factor. Lower is better quality. 18–28 is the useful range.
Encoder speed: Choose between Ultrafast, Very fast, Medium, Slow.
Video bitrate: Leave empty to let CRF decide. Setting this switches to fixed-bitrate encoding.
Audio: Choose between Keep audio, Remove audio.

Worth knowing before you start

All clips are normalised to a shared resolution and frame rate first, so mixed sources join cleanly.

Measured, not estimated

What this tool actually does to a file

Joining two copies of the same two-second clip into one.

On every sample measured, the result came out larger — 3.1× larger at best and 4.8× larger at worst.

Each row is one document, chosen because this tool behaves differently depending on what is inside the file.
Sample	In	Out	Change
An easy clipThe compressible end of the range — a clean tone, or a moving test pattern — where a codec does its best work.	142 KB	447 KB	3.1×
A hard clipThe other end — pink noise, or dense video grain. Close to incompressible by design, and the worst case for every codec.	2.0 MB	9.5 MB	4.8×

Produced by this site's own converter. The same code that runs in your browser, at the same default settings, so these are the bytes you would download.

Samples are generated from a fixed seed rather than taken from real photographs or documents, so the corpus is reproducible and carries no licensing question — and so the numbers predict the shape of your result rather than its exact size. Measured 2026-10-01. The method, and the command that regenerates every figure on this page, are on the how it works page.

About these formats

Accepts

MPEG-4 Part 14

The default video container of the internet.

Extensions: .mp4, .m4v
MIME type: video/mp4
Best for: Sharing anywhere · Streaming · Social media
Compatibility: Plays on effectively every device.

Accepts

QuickTime Movie

Apple's QuickTime container, common from iPhones and cameras.

Extensions: .mov, .qt
MIME type: video/quicktime
Best for: Apple ecosystem · Video editing
Compatibility: Excellent on Apple, patchy on Windows and Android.

All clips are normalised to a shared resolution and frame rate first, so mixed sources join cleanly.

Good to know

Merge Videos — questions

How does Merge Videos work?

Join several clips into one continuous video, in the order you arrange them. Add your files above, adjust anything you want to change, and press the button. The result downloads straight to your device.

Is there anything I should watch out for?

All clips are normalised to a shared resolution and frame rate first, so mixed sources join cleanly.

Is Merge Videos safe — are my files uploaded to a server?

No, nothing is uploaded. On most online tools, pressing the button copies your file across the internet onto a computer owned by that website, where it is processed and then sent back. That copy is what "upload" means. This tool does not do it: your file is read and processed by the browser you are using right now, stays on this device the whole time, and is discarded when you close the tab. Turn off your Wi-Fi after the page loads and it still works, which is the quickest way to confirm it.

Can I use this on confidential or personal documents?

Yes — that is the case it was built for. Because the file never leaves your device, a confidential document is no more exposed than it is sitting in your own folder: there is no transfer, no copy on anybody else's hardware, no retention period and no staff with access. Nothing about the file is logged either — not its name, not its size, not its contents.