Direct answer: Watermarking a video burns a text or logo overlay into every frame. Done in the browser it's free and private — your file never uploads. Working defaults: watermark at 8-12% of frame width, 40-70% opacity, inset 5% from the edge, bottom corner. The pass re-encodes the video, so a 3-minute 1080p clip at 8 Mbps comes out around 180 MB (megabits ÷ 8 × seconds).
This tool adds watermarks — it does not remove them. It's built for creators protecting their own work with attribution. Removing a watermark from someone else's video is content theft; we don't build that, and the damages can run $750-$150,000 per work.

1. Choose Your Video

Select a video file or drop it here — it stays on your device

MP4, WebM, or MOV from your camera roll or editor.

2. Watermark Settings

Pick a video to preview the watermark on a real frame.

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Output Size Math — Bitrate × Duration

ResolutionTypical bitrateMB per minute3-minute video
720p5 Mbps37.5 MB112.5 MB
1080p8 Mbps60 MB180 MB
1080p12 Mbps90 MB270 MB
4K35 Mbps262.5 MB787.5 MB
4K45 Mbps337.5 MB1,012.5 MB

The formula is exact: bitrate in megabits per second ÷ 8 × seconds = megabytes. A 3-minute 1080p video at 8 Mbps is 8 ÷ 8 × 180 = 180 MB. Your watermarked output lands near these figures when the re-encode bitrate matches the source.

Watermark Sizing Rules That Hold Up

SettingWorking rangeWhy
Width8-12% of frame widthReadable on a phone screen, unobtrusive on a TV
Opacity40-70%Below 40% it washes out on bright scenes; above 70% it dominates
Edge margin~5% of widthClears the crop some players apply and corner UI
PositionBottom cornerBottom-center is where platform progress bars live
YouTube branding watermark150×150 px min, under 1 MBPNG, GIF (no animation), JPEG, or BMP; transparent PNG recommended

The YouTube row is the platform's published spec for the subscribe-button watermark in YouTube Studio; the rest are durable best practice for burned-in marks.

How the Video Watermark Tool Works

Watermarking tools split into two camps: servers that upload your video (slow, private nowhere) and browser engines that process locally. This is the second kind — canvas draws each frame with your watermark, and the browser's own recorder writes the result.

The engine

Your video plays into an offscreen element; every frame is drawn to a canvas with the watermark text rendered on top at your chosen position, size, color, and opacity. The canvas stream plus the video's audio track feed a MediaRecorder, which writes a WebM (or MP4 on supporting browsers) entirely on your device. Processing runs at roughly the video's real length — a 4-minute clip takes about 4 minutes.

How to use it

Select a file, then tune the watermark against the live frame preview: type your text, drag size and opacity until it reads clearly without shouting, and pick a corner. Hit the watermark button and download when the progress bar completes. Nothing was uploaded anywhere.

A worked example

Take a 1920×1080 clip. At the default 10%-width sizing (roughly a 6%-height font), the watermark text spans about 192 pixels. The 5% margin keeps it 96 pixels off the edges, anchoring a bottom-right mark at roughly x=1632, y=984 — safely inside every player's crop zone. For the file itself: 3 minutes at a typical 1080p bitrate of 8 Mbps means 8 ÷ 8 × 180 = 180 MB in, about the same out. The 720p version of the same clip at 5 Mbps would be 112.5 MB.

Frequently Asked Questions

Is this video watermark tool really free and private?

Yes. The tool runs entirely in your browser using canvas and MediaRecorder — your video never leaves your device, there is no upload, no account, and no watermark added to your output other than the one you configure. The only cost is the time the render takes, which runs at about the length of the video.

What format does the watermarked video come out in?

Usually WebM (VP9 or VP8 video plus Opus audio), the default recording format of Chrome, Edge, and Firefox. Where the browser supports MP4 recording — Safari on newer versions — the tool offers it automatically. Any modern player and every major platform accepts WebM uploads.

Where should a video watermark go?

A bottom corner, inset by about 5% of the frame, is the durable default: visible on every platform, clear of platform UI that overlays the bottom-center, and away from the center of attention. Watermarks near edges get cropped by some players; centered ones obstruct content. Size 8-12% of frame width at 40-70% opacity is the standard working range.

Does adding a watermark reduce video quality?

Burning in a watermark requires re-encoding, and any re-encode loses a little quality. At a bitrate matching your source — about 8 Mbps for 1080p — the difference is invisible in practice. The output size math is simple: megabits per second divided by 8, times seconds, gives megabytes, so a 3-minute 1080p video at 8 Mbps is roughly 180 MB.

Can this tool remove watermarks from videos?

No, and it never will. This tool exists for creators protecting their own work by adding attribution. Removing a watermark from someone else's video is copyright infringement and routinely ends in takedowns and damages claims, so we don't build it, link it, or describe how to do it.

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