100% private · runs in your browser

Merge clips into one MP4

Drop the videos, set the order, hit merge — all in your browser, nothing uploaded.

1 Add your clips

Nothing leaves your device

FFmpeg WebAssembly runs locally inside your browser tab. Your clips never travel over the network.

Drag to reorder

Reorder clips with a drag, the up/down buttons, or keyboard arrows. The merged file plays them top-to-bottom.

Lossless when possible

Matching clips stream-copy in seconds. Different sizes trigger a clean re-encode automatically.

How to merge videos in your browser

  1. 1

    Add two or more clips

    Drop your videos into the box above or click to pick them. MP4, MOV, WebM and MKV all work. First run loads the FFmpeg engine (~30 MB) and caches it.

  2. 2

    Drag clips into order

    The merged file plays clips top-to-bottom. Drag rows with the grip handle, use the arrow buttons, or focus a row and press Alt+↑/↓.

  3. 3

    Click Merge and download

    Hit Merge Videos and the tool joins everything into one MP4 ready to download. The output keeps the first clip's dimensions; mismatched clips are letterboxed to fit.

Frequently asked questions

How do I merge two videos into one file?

Drop both videos into the tool, drag them into the order you want, then click Merge Videos. The combined MP4 downloads to your device.

What size will the merged video be?

The output keeps the first clip's dimensions. If other clips are a different size, they are letterboxed to fit (centered with black bars), so portrait and landscape can be merged together without distortion.

Is it safe to merge personal videos here?

Yes. FFmpeg runs as WebAssembly inside your browser tab — there is no upload step. You can confirm this in your browser's Network tab while the tool runs.

Will the merged video have a watermark?

No. The output is a clean MP4 with no logos, watermarks or branded intros.

Why does the first merge take a moment?

The first run loads the FFmpeg WebAssembly engine (~30 MB) into your browser cache. After that, runs start instantly.

Trim a clip before merging

Cut each video down to just the part you need, then merge them here.

Merge PDFs the same way

Combine ID front & back or multiple documents into one PDF file.