About this tool
A watermark is a visible mark - text, logo, or both - overlaid on an image to claim ownership, deter unauthorized use, or brand a piece of content. Photographers use them on portfolio images. Brands use them on social media graphics. Real estate listers use them on listing photos.
This tool adds a text or image watermark in your browser. You can position it anywhere (corners, center, custom X/Y), set opacity (0-100%), tint, font family, and font size. Bigger is more visible but more intrusive; opacity 30-60% on the bottom-right is the photographer-standard placement.
How it works
Open your image
Drop or pick the photo you want to watermark.
Pick text or logo
Type a name / brand for a text watermark, or upload a transparent PNG logo.
Position and style
Pick a corner or set custom X/Y. Adjust opacity (try 35-50%), tint white or black, and font size.
Download
The watermarked image saves as PNG. The original is untouched - rerun for different placements.
Use cases
Photographer portfolios
A small "© Name" in the bottom-right corner discourages unauthorized re-use without dominating the image.
Real estate listings
Agent name + logo on listing photos so the photo stays branded if shared on Zillow / MLS.
Social media branding
Logo + handle in the corner of a quote graphic ensures attribution if it gets cropped or screenshot-shared.
Document samples
Send a "DRAFT" or "SAMPLE" diagonal across an unfinished design without sending the editable source file.
Format and spec details
| Watermark types | Text (custom string + font) or Image (transparent PNG) |
|---|---|
| Position presets | Top-left, Top-right, Bottom-left, Bottom-right, Center, Tile |
| Opacity range | 0% (invisible) - 100% (solid) |
| Best practices | 30-60% opacity, bottom corner, 4-8% of image width |
Tips and best practices
- Subtle wins. A 35% opacity logo in the corner is more professional than a 90% banner across the middle.
- Use a transparent PNG for a logo watermark - JPG has no transparency.
- For maximum protection, tile the watermark across the full image at 15% opacity. Hard to remove without artifacts.
- Keep an unwatermarked copy. You will need it for re-edits.
How to use the Image Watermark
The Image Watermark is a browser-based tool that runs entirely on your device. Inputs you enter never reach a server - all calculations happen client-side in JavaScript. This means:
- Privacy: nothing is logged, sent, or stored by 3Tej. Inputs disappear when you close the tab.
- Speed: results update as you type. No network round trip.
- Offline use: once the page is cached, it works without internet.
- No signup: no account, no email, no rate limits.
Step by step
- Enter your inputs in the form above. Each field is labeled with its unit (currency, percent, kg, etc.) and the expected range.
- Read the result as it updates. The number reflects the formula commonly accepted in Image Watermark-related calculations.
- Adjust to see sensitivity: change one input at a time and watch how the output moves. This is the fastest way to understand which variable matters most.
- Copy or screenshot the result for later reference. The page state persists for the session if your browser allows it.
When you would use this
- Quick estimates: when you need a number now and don't want to open a spreadsheet.
- Sensitivity analysis: testing how a result changes as inputs vary, before committing to a real-world decision.
- Comparison: running the same calculation with different inputs to compare options side by side.
- Learning: building intuition for how the underlying math behaves.
- Documentation: capturing a snapshot of inputs and outputs at a point in time.
Privacy and offline operation
Every operation in this tool runs client-side using your browser's built-in APIs (Canvas, Web Audio, WebAssembly). No data is uploaded. After the initial page load you can disconnect from the internet and the tool keeps working.
We use Google Analytics and AdSense for the page itself, but neither sees the content of the files you process.
Frequently asked questions
Can a watermark be removed?
A skilled retoucher can mask out a corner watermark with content-aware fill. Tile watermarks (a small mark repeated across the image) are much harder to remove. Watermark is a deterrent, not a guarantee.
Should watermarks be in white or black?
Depends on the image. White on dark, black on light. A 50% gray with shadow works in most cases. Try both at 35% opacity.
What is the right size?
Roughly 4-8% of image width for a subtle corner mark, 15-25% for a tiled / center watermark.
Does watermarking add a copyright?
No - copyright exists from the moment of creation regardless of marking. The watermark just makes the claim visible and traceable.
Is the Image Watermark accurate?
The Image Watermark applies the standard formula for image watermark. Accuracy is limited only by your input precision. For decisions with material consequences, use the result as a starting point and verify with a qualified professional or the relevant official source.
Is the Image Watermark free?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads that appear around the tool but not inside the calculation flow.
Are my inputs saved?
No. Inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but does not see what you type into the form.
Can I use the Image Watermark on my phone?
Yes. The tool is responsive and tested on iOS Safari, Android Chrome, and major desktop browsers. Touch targets meet Apple's 44pt and Google's 48dp minimum guidance.
How do I report a bug or suggest improvement to the Image Watermark?
Email hi@3tej.com with the URL of this page and a description of what you saw vs expected. We typically respond within 72 hours and update calculators when rules or formulas change.
How accurate is the Image Watermark?
It applies the standard formula. Accuracy is limited only by your input precision. For decisions with material consequences (taxes, medical, legal, structural), use the result as a starting point and verify with a qualified professional in the relevant field.
Is the Image Watermark free to use?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads around the tool but not inside the calculation flow.
Are my inputs saved anywhere?
No. All inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but the analytics never see what you type into the form.
Does the Image Watermark work offline?
Yes. Once the page has loaded, it works without internet. The calculation runs in JavaScript on your device.
Can I share results from the Image Watermark?
Take a screenshot or copy the output. The page doesn't generate shareable URLs for specific calculations - inputs stay in your browser only.
Why are the results different from another image watermark tool?
Most likely: different formula assumptions, different default values, different rounding rules, or different applicable rates. Check the methodology if both tools document it. Both can be valid for different scenarios.