Merge Videos in Your Browser
Join multiple clips into one MP4 — losslessly when they match, with automatic re-encoding when they don't. Nothing is uploaded.
Merge two or more video clips into a single MP4 directly in your browser. When the clips share the same codec and resolution (like parts recorded on the same phone), they are joined losslessly in seconds; mixed clips are automatically normalized and re-encoded. Your files never leave your device.
Choose a file or drop it here
🔒 Processed locally — never uploaded.
Phone recordings arrive in pieces: the camera app splits long takes, screen recorders restart, and suddenly one moment lives in three files. This tool joins them back together. Matching clips — same codec, same resolution, the normal case for parts from one device — are concatenated losslessly in seconds. Mixed clips are normalized to the first clip's resolution and re-encoded cleanly. Select the files in the order you want them joined, press merge, download one MP4.
How it works
- Select two or more clips (or drop them together) — the order you pick them is the order they are joined.
- Press Merge clips. Matching files are joined with a lossless stream copy; mixed files are normalized and re-encoded automatically.
- Press the download button for the combined MP4. The badge tells you which path ran.
Common uses
- Rejoin a long phone recording that the camera app split into segments.
- Combine several screen-recording takes into one continuous demo.
- Stitch clips from an event into a single shareable video.
- Assemble before/after or multi-part footage without opening an editor.
Supported formats and limits
| Input | Two or more MP4/MOV/WebM clips — same-source clips take the lossless path |
|---|---|
| Output | One MP4 — lossless concat when clips match (codec + resolution), otherwise H.264/AAC re-encode normalized to the first clip's size |
| Speed | Lossless path: seconds. Re-encode path: roughly 1.5x the combined length |
| Maximum file size | 500 MB combined (in-browser memory limit) |
| Where it runs | Entirely in your browser (WebAssembly) — keeps working offline once loaded |
Frequently asked questions
Are my videos uploaded while merging?
No. The merge runs inside your browser using FFmpeg compiled to WebAssembly. Your files never leave your device.
In what order are the clips joined?
The order you select them in the file picker (or drop them). To control the order precisely, add clips one at a time — each new selection is appended to the list.
When is the merge lossless?
When every clip shares the same video codec, resolution and audio setup — the normal case for segments recorded by the same device or app. The tool checks this automatically and copies the streams bit-for-bit when possible.
What if my clips have different sizes or codecs?
They are normalized to the first clip's resolution and re-encoded to H.264/AAC. The badge will say 're-encoded' so you know which path ran.
Is there a size limit?
The combined total should stay under 500 MB, since all clips are held in browser memory during the merge.
Is this free?
Yes — free, no signup, no watermark, no queue. Processing happens on your device, so there is nothing for us to meter.