Watermark PDF — Add Text or Image Stamp
Add a text or image watermark to any PDF instantly in your browser. Pro Mode adds custom fonts, opacity, rotation, position and per-page control.
How to Watermark a PDF
From an unmarked file to a stamped, downloadable PDF in a few clicks — no signup, nothing ever leaves your browser.
Everything above runs entirely in your browser — your PDF is never uploaded to a server, so your document stays completely private from start to finish.
Watermark PDF Online — Add Text or Image Stamps for Free
Watermarking a PDF stamps text or an image onto every page — a "DRAFT" mark, a company logo, a confidentiality notice — without altering the original content underneath. This tool renders the preview with pdf.js and applies the watermark using pdf-lib, both running locally in your browser, so the document being marked confidential never itself gets uploaded anywhere to add that mark.
A watermark serves a simple purpose: it tells anyone looking at the document something about its status before they read further — that it's a draft, that it's confidential, that it belongs to a specific company or person. Adding one usually shouldn't require installing desktop software or signing up for an account just to stamp a single file. This tool covers that core workflow entirely free, with six one-click text presets (CONFIDENTIAL, DRAFT, DO NOT COPY, SAMPLE, TOP SECRET, FOR REVIEW) alongside full custom text.
Pro Mode (also free) adds the fine control a business or design use case usually needs: custom font, size and rotation, seven position/style options including tiling, page-range targeting, and — notably — image watermarks, so a company logo or signature graphic can be stamped instead of text.
1Simple vs Pro — Watermark Control
| Feature | Simple Mode | Pro Mode (Free) |
|---|---|---|
| Text watermark, 6 quick presets + custom text | ✓ | ✓ |
| Opacity, angle and colour control | ✓ | ✓ |
| Bold text / outline-only style | ✓ | ✓ |
| Custom font (5 options) | — | ✓ |
| 7 position/style options incl. tiling | — | ✓ |
| Apply to specific pages or a custom range | — | ✓ |
| Image / logo watermark upload | — | ✓ |
| Tile spacing control | — | ✓ |
2Common Reasons People Watermark a PDF
A "DRAFT" watermark prevents an in-progress version of a document from being mistaken for the final one if it circulates before it's ready. A photographer or writer sharing a sample often stamps it to discourage reuse before payment. Businesses sending contracts for review commonly mark them "FOR REVIEW" so no one signs the wrong version. In every case, the mark needs to be visible enough to notice but light enough not to interfere with actually reading the document — which is exactly what the opacity control is for.
3Getting the Opacity and Position Right
| Opacity Range | Best For |
|---|---|
| 5–15% | Subtle branding that shouldn't distract from the content |
| 15–25% | Standard "DRAFT" or "CONFIDENTIAL" marks — the default is 18% |
| 25–40% | A clearly visible warning on sensitive documents |
| 40–60% | A bold, unmissable stamp — best for a diagonal, single-instance mark |
Diagonal placement at 30–45° is the most common choice because it's immediately recognizable as a watermark rather than being mistaken for actual page content, and it stays legible across both portrait and landscape pages. Tiling — repeating the mark across the entire page rather than once in the center — adds a stronger anti-copy deterrent, since cropping out a single corner mark no longer removes the watermark entirely. A text watermark alone doesn't function as legal proof of ownership or a digital signature — it's a visible deterrent and a status indicator, not encryption or access control. For documents that need genuine access restrictions, password protection is a separate step; a watermark's job is simply to make the document's status obvious at a glance.
Watermarking here runs entirely with pdf.js and pdf-lib inside your browser tab — the same is true whether the source document is a signed contract, an unpublished manuscript, or a confidential internal report. Nothing about its content is ever sent anywhere to add a stamp to it.
4Frequently Asked Questions
Built on real, open-source libraries — page rendering runs on pdf.js and the watermark itself is written into the document with pdf-lib, following the ISO 32000 PDF specification rather than a proprietary format.
Related Tools
The rest of PDF Studio — other free PDF tools that pair well with watermarking