Blur part of a video
Mark what to hide on one frame; it stays hidden for the whole clip.
Drop files here
or click to choose from your deviceAccepted: MP4, M4V, MOV
One file per runUp to 150 MB per file5 runs per dayRemove limits with Pro✓ Works offline
Your files stay on your device
This tool runs entirely in your browser. Nothing is uploaded, nothing is stored, and you can even turn off your internet connection before you start.
Example
Example: an email address hidden in a 1080p screen recording
A three-minute tutorial recorded at 1920 × 1080 shows your email address at the top right of the browser the whole time. Drop the MP4, drag one box over the address on the frame shown, choose Mosaic (pixelate) and leave Strength at 5.
- The mosaic is sized from the video’s longer side: at strength 5 on a 1920-pixel-wide video each block is 38 pixels, so the address becomes a few flat squares.
- The box stays where you put it for the whole clip, which is right for a screen recording: the address never moves.
- Press Hide marked areas. The new video is an MP4 named after the original with -pixelated added, with the sound as it was.
| Strength | Mosaic block, 1080p | Blur radius, 1080p |
|---|---|---|
| 1 | 8 px | 3.8 px |
| 3 | 23 px | 11.5 px |
| 5 | 38 px | 19.2 px |
| 8 | 61 px | 30.7 px |
| 10 | 77 px | 38.4 px |
The same three minutes with the address unreadable in every frame. A licence plate on a parked car filmed from a fixed spot works the same way; for faces that move, use Blur faces in a video.
How it works
- Drop an MP4 or MOV video onto the box.
- Drag a box over each area to hide on the frame shown.
- Choose mosaic, blur or a black box, and the strength.
- Press Hide marked areas and download the new MP4. The sound is kept as it was. That holds for AAC sound, which phones record; another kind (PCM in a camera MOV) is left out, and the result says so.
Frequently asked questions
- Does the box follow a moving face?
- No, and it is not trying to: the areas stay where you put them for the whole video, which is what suits a fixed camera, a screen recording or a name on a sign. For a face that moves, use Blur faces in a video, which looks at every frame and follows the person. For anything else that moves — a plate on a moving car — make the box large enough to cover its path, or trim the video into parts first.
- How strong should the mosaic be?
- Strong enough that the blocks are bigger than the letters. Strength sets the block size from the video’s longer side: on 1080p, 8 pixels at 1, 38 at 5 and 77 at 10. Small text is gone at 5; a large sign or a face close to the camera may need 8 or more. Blur at the same strength uses a radius of half the block.
- Can I hide several areas at once?
- Yes. Drag a box over each one on the frame; all of them get the same effect and strength. For text that must never be read again, the solid black box is the safest: it replaces the pixels completely, where mosaic and blur keep a little of the original colour.
- Which browsers work?
- Chrome and Edge on a computer or Android, and Safari 16.4 or newer.
- Is the video uploaded?
- No. It is decoded, covered and encoded again in your browser.