Free · no sign-up · runs in your browser
Video Watermark Tool
Pick a clip (≤60 seconds · any file size), type your watermark text, then drag the three sliders for opacity, count and spacing. Hit render and the watermarked video is drawn right on your device — the file never leaves it.
Add the watermark
Three steps: pick a video → type the text → drag the sliders and render. The render happens on your device, so nothing gets uploaded.
English, Chinese or symbols — up to 30 characters. Stick to common characters: rare glyphs or emoji may show up as boxes.
The preview uses your own system fonts; once a video is picked it is drawn over a real frame and matches the exported file.
Result
How it works
Drag in or select an mp4 / mov — any file size works, because the render never uploads it. Only clips over 60 seconds are flagged.
Opacity, count and spacing show up live in the preview, with the current value next to each slider.
One button draws the tiles on a canvas, records the clip on your device and offers the finished file for download.
Why it is built this way
The watermark is drawn on a canvas and encoded with MediaRecorder, so the clip is never uploaded, there is nothing to leak and no size cap to hit.
No scaling and no downsampling: the export is encoded at a bitrate matched to your pixel count, at the source resolution, frame count and duration.
There is nothing to choose: if a browser cannot record canvas video, the same button sends the clip to the ffmpeg fallback and returns a standard H.264 + AAC mp4 in the source resolution.
FAQ
Is there a file-size limit?
No. The render keeps the clip on your device, so a 500MB 4K export is as welcome as a 3MB phone clip — big files only mean the render takes longer. The one cap is duration: clips over 60 seconds are refused, and if the server fallback takes over, keep the file under 15MB.
What comes out of the render?
Chrome and Edge usually hand back a webm, Safari an mp4; the fallback server render always returns a standard H.264 + AAC mp4. Either way you get the source resolution and the same length, and the download button is right under the player.
Does the watermark cost me video quality?
No scaling is applied — resolution, duration and audio stay the same as the source. The export uses a bitrate matched to your pixel count, and the rare fallback render encodes at CRF 18 (visually near-lossless) instead of a low-quality preset.
Which formats work?
mp4 / mov (H.264) only. Nothing is transcoded and exotic containers are rejected; the resolution is never scaled up or down.
Is there a length limit on the watermark text?
30 characters max. The render button stays disabled when the box is empty, and the counter next to it turns red past the limit. Rare glyphs and emoji can render as boxes, so prefer common characters.
How long are results kept?
Your own render lives in the browser tab as a blob — download it before you close the page. A fallback server render sits in the system temp directory and is deleted after 15 minutes, so an expired link just means rendering again.