What it does
Watermark PDF puts words across your pages, such as DRAFT, CONFIDENTIAL or COPY, or your own text. You choose the size, angle, colour and how see-through it is. Or choose a stamp (Received, Approved, Paid) with today’s date, placed in a corner inside a box.
It works on all pages or only the ones you list, like 1-3,5. It also works on JPG and PNG pictures, which suits a copy of an ID marked “Copy for bank use only”. Nothing is uploaded or kept. When you are done, add numbers with page numbers or reorder pages with organise PDF.
How to use it
- Choose a PDF or picture.
- Pick Text across the page or Stamp with date.
- Set the words, size, angle, opacity and colour. Pictures show a live preview.
- For a PDF, type page ranges to mark only some pages, or leave it blank for all.
- Press Add watermark and download.
What each setting does
- Opacity: 100 is solid; 20 to 30 lets the page show through.
- Angle: 45 runs from bottom left to top right; 0 is flat.
- Size: for PDFs it is in points; on pictures it scales with the picture width.
- Stamp corner: where the dated box goes.
Worked example
You are sending a 3-page quote for review. Choose Text, type DRAFT, size 90, angle 45, opacity 25. The saved PDF still has 3 pages and each shows a faint red DRAFT across the middle.
FAQs
Can someone remove the watermark? On a PDF it is drawn on the page and is not a security feature; a determined person can edit it out. For ID copies, a visible mark with who and why discourages misuse.
Which letters work? Latin letters, numbers and common symbols.
Does it keep my picture? No. The picture is marked in your browser and saved to your device only.
Where the numbers come from
- Marks are drawn with pdf-lib (PDF) and the browser canvas (pictures), using standard fonts. Nothing else is used.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-10.