How to Add a Watermark to a PDF (Free, In Browser)
Updated 2026-06-21
To add a watermark to a PDF, open your file in a stamping tool, type the text you want (such as CONFIDENTIAL or DRAFT), set the opacity, and download the new PDF. With PDF Watermark & Page Numbers this happens entirely in your browser — the file is read, stamped, and re-saved in the tab, so nothing is ever uploaded to a server.
Add a diagonal text watermark
A watermark is a piece of text laid diagonally across every page so the document is clearly marked without hiding the content underneath.
- Open PDF Watermark & Page Numbers and select your PDF.
- Type your watermark text — common choices are CONFIDENTIAL, DRAFT, SAMPLE, or a company name.
- Set the opacity so the text shows through without obscuring the page. Around 0.15 (15%) is a good default — light enough to read the document, dark enough to read the mark.
- Choose a font size in points. Larger sizes (around 60pt) span the page corner to corner; smaller sizes sit more compactly.
- Download the stamped PDF.
The watermark is drawn at a 45-degree angle and centered on each page, in gray, so it reads consistently on light backgrounds. Your original file stays untouched — the tool produces a new copy.
Add page numbers at the same time
You can number every page in the same pass. Turn on page numbers and pick a format:
- Page 1 of 12 — the most legible for printed reports.
- 1 / 12 — compact, good for slide-style PDFs.
- Page 1 — when the total page count is not needed.
- 1 — a bare number for minimal footers.
Choose where the number sits: bottom-center, bottom-left, bottom-right, or top-right. There is also a start-at value, so a chapter that begins on page 5 of a larger work can be numbered to match. This is handy for Bates-style sequential numbering across a stack of legal or invoice pages — set the starting number and the count flows from there.
When to use a watermark
- Marking drafts so reviewers never mistake a work-in-progress for the final version.
- Flagging confidential material before sharing a contract, report, or proposal.
- Branding handouts with a company or event name.
- Numbering combined PDFs so a merged packet reads as one continuous document.
A worked example: you are sending a 20-page proposal for internal review. Open the PDF, type DRAFT, set opacity to 0.15 and size to 60pt, enable Page X of Y in the bottom-center, and download. Every page now carries a faint diagonal DRAFT mark and a clean footer like Page 7 of 20.
A note on privacy
Many online watermark tools upload your PDF to their servers to process it — a problem when the document is a contract, a financial statement, or anything marked confidential. This tool runs the stamping locally with the pdf-lib library inside your browser. Nothing leaves your device, there is no signup, and there is no copy of your file sitting on someone else's server afterward.
Ready to mark your document? Open PDF Watermark & Page Numbers and stamp your PDF in seconds.