Add a text watermark to every page of a PDF — “CONFIDENTIAL”, “DRAFT”, “SAMPLE”, or any words you choose. Pick diagonal or horizontal, set the opacity and size, and download the watermarked file. It runs entirely in your browser: free, no sign-in, and your file never leaves your device.
How the watermark tool works
The tool reads your PDF in your own browser and stamps your words on every page — the same text, in the same place, on page 1 and on page 100. In diagonal mode the words run at -45 degrees across the middle of the page, the classic “CONFIDENTIAL” look. In horizontal mode they run straight across. The grey text is drawn at the opacity you set, so the page underneath stays readable: at 30% opacity the watermark is clearly visible but the document text shows through it.
Nothing is uploaded to a server. Your PDF is processed on your own device, so it works on any connection and your documents stay private. The watermarked file downloads with a clear name, for example “contract-watermarked.pdf”, and your original file is never changed — you can watermark the same file again with different words whenever you like.
A watermark is the grey word stamped across a page — “CONFIDENTIAL”, “DRAFT” or “SAMPLE” — that says how a document should be handled before anyone reads a line of it. The Watermark PDF tool adds that mark to every page of a PDF in one go: choose your PDF, type the words, pick diagonal or horizontal, set the opacity and size, and download the watermarked file. It runs entirely in your browser: free, no sign-in, and your file never leaves your device.
A watermark is not an edit to your document’s text. It is a separate layer of grey letters drawn over each page, faint enough that the page underneath stays readable. That is the whole point: the reader can still use the document, but the mark is there on every page, and a photocopy or a screenshot carries it too.
How to use the tool, step by step
Five choices, then one click. The tool shows a live summary of your settings before you stamp anything, so what you see is what every page gets.
- Step 1 — Choose a PDF. Drop a PDF file onto the box, or click it to choose one from your device. PDF files only, up to 50 MB. As soon as it loads, the tool shows the file name and how many pages it has — check that number before you watermark, so you know how many pages will be stamped.
- Step 2 — Type the watermark text. The words stamped on every page, up to 60 characters. “CONFIDENTIAL” is filled in for you; change it to “DRAFT”, “SAMPLE”, your company name, or anything else. The same text goes on every page.
- Step 3 — Pick an angle. Diagonal (the default) runs the words at -45 degrees across the page, from bottom-left to top-right — the classic confidential-document look. Horizontal runs the words straight across the page.
- Step 4 — Set the opacity. The slider runs from 10% to 100%, starting at 30%. Lower opacity is fainter and lets the page underneath show through; higher opacity is bolder. 30% is a good starting point for a document people still need to read.
- Step 5 — Choose the position and size. Position is Center (the default), Top, or Bottom. Font size runs from 12 to 200 points and starts at 48 pt — big enough to read at a glance on a full page, while 24–36 pt suits a short word at the top or bottom.
- Step 6 — Add the watermark and download. Press “Add Watermark”. The watermarked file appears below as a download link, named after your original file — “contract.pdf” becomes “contract-watermarked.pdf”. Your original file is never changed.
Diagonal or horizontal — which to pick
Diagonal is the usual choice for a document-wide mark. At -45 degrees the words cross the middle of the page, so they are visible wherever the reader looks, and they sit over both text and empty space. A diagonal “CONFIDENTIAL” on a 2-page contract is readable at a glance and hard to crop out of a screenshot, because it spans the whole page.
Horizontal suits a quieter mark. A horizontal “DRAFT” at the top of each page, at 20% opacity and 36 pt, labels the document without sitting over the body text. It is the better pick when the pages are dense — a report or a form where a diagonal mark would cross the figures — and when the watermark is a status label rather than a warning.
Worked examples
Example 1 — a 2-page contract, “CONFIDENTIAL”, diagonal, 30% opacity, 48 pt, center. The tool stamps “CONFIDENTIAL” across the middle of both pages at -45 degrees. The page count stays 2 — watermarking adds text, never pages. The file downloads as “contract-watermarked.pdf”, and the grey words are visible on page 1 and page 2 while the contract text underneath stays readable.
Example 2 — a 10-page report, “DRAFT”, horizontal, 20% opacity, 36 pt, top. Every one of the 10 pages gets “DRAFT” in grey across the top, faint enough that nothing on the page is hidden. Ten pages in, ten pages out — the same 10-page file, with the same words at the top of each page. This is the right setting for a document that is still being reviewed: the status is obvious, and the content is untouched.
Example 3 — a 5-page sample, “SAMPLE”, diagonal, 50% opacity, 60 pt, center. A bolder mark for a document you are sharing before it is final: 60 pt letters at half opacity run diagonally across all 5 pages. The pages underneath are still readable, but the word “SAMPLE” is unmistakable — a reader cannot mistake the file for the finished version.
Opacity, size and readability
Opacity is how solid the grey letters are. At 30% opacity the letters are 30% grey and 70% see-through, so the document text underneath shows through them. At 10% the mark is a faint ghost — visible, but easy to miss. At 100% the letters are solid grey and will cover whatever sits behind them, so save full opacity for a short word on a mostly empty page.
Font size works the same way. 48 pt is the default because it reads clearly across a full page without swallowing it. On a long word like “CONFIDENTIAL” (12 letters), 48 pt spans about half the width of an A4 page diagonally — big enough to notice, small enough to fit. Drop to 24–36 pt for a top or bottom mark, and go up toward 100–200 pt only for a single short word you want to dominate the page.
The watermark colour is a fixed mid-grey. Grey is the standard for watermarks because it reads as a label, not as part of the document: black would look like body text, and a colour would draw the eye away from the content. Grey at 30% opacity is visible on white paper, on a printed page, and in a screenshot.
Common mistakes
- Leaving the text box empty. The tool needs words to stamp. If the box is empty, it asks you to type the watermark text first — “CONFIDENTIAL”, “DRAFT”, or anything else up to 60 characters.
- 100% opacity over dense text. Solid grey letters hide the words behind them. If the page is full of text, stay at 30% or below, or move the mark to the top or bottom.
- A watermark that is too small to notice. 12 pt at 10% opacity is barely there. If the point of the mark is that nobody misses it, use at least 30% opacity and 36 pt or larger.
- Expecting the original to change. Watermarking never edits your original PDF. The watermarked file is a new copy — download it and use that copy. The original stays whole, without any mark.
- Expecting the watermark to be unremovable. A watermark is a visible label, not a lock. Anyone with a PDF editor can delete the watermark layer, so it marks a document’s status — it does not protect it. For a file that must not be changed, keep the original safe and share only the watermarked copy.
- Watermarking a password-protected PDF. The tool cannot open a PDF that asks for a password. Open it with the password and save an unprotected copy, then watermark that copy.
Related tools
The watermark PDF tool sits in the File & Image group, and the companion tools below cover the rest of a PDF workflow.
- Compress PDF — shrink a PDF before you share it, for example a watermarked file that is too large to send.
- Split PDF — pull just the pages you need out of a PDF, then watermark only the pages you share.
- PDF Merger — combine several PDFs into one file, then watermark the whole document in a single pass.
- Sign PDF — add your signature to a PDF, for example the watermarked copy of a contract.
- PDF to Word — turn a PDF into an editable Word document when you need to change the text rather than mark it.
- PDF to JPG — turn PDF pages into images, for example to share one watermarked page as a picture.
- JPG to PDF — turn images back into a PDF, then watermark the result.
- Excel to PDF — turn a spreadsheet into a PDF first, then stamp it “DRAFT” or “CONFIDENTIAL” before sharing.
For all of ToolZana’s free tools, start at the ToolZana home page.
Tips for clean watermarks
- Check the page count first. The tool shows it as soon as your file loads. The watermark goes on every page, so a 10-page report gets 10 marks — make sure that is what you want before you stamp.
- Start at 30% opacity and 48 pt. That combination is visible without hiding the text underneath, and it works for most documents. Adjust from there: fainter for dense pages, bolder for a warning.
- Keep the words short. One or two words — “CONFIDENTIAL”, “DRAFT”, “SAMPLE” — read at a glance. A long sentence across the page is hard to read diagonally and covers more of the document.
- Use diagonal for warnings, horizontal for labels. A diagonal mark says “handle with care”; a horizontal mark at the top says “this is a draft”. Pick the one that matches what the words mean.
- Keep the original. The watermarked file is a copy. Keep the original PDF until you have checked the watermarked file opens correctly — then share the watermarked copy and file the original away.
- Password-protected files need unlocking first. The tool cannot open a PDF that asks for a password. Open it with the password and save an unprotected copy, then watermark that copy.
The short version
The Watermark PDF tool stamps your words on every page of a PDF — “CONFIDENTIAL”, “DRAFT”, “SAMPLE”, or any text up to 60 characters — in grey, at the angle, opacity, position and size you choose. A 2-page contract stamped “CONFIDENTIAL” diagonally at 30% opacity and 48 pt stays 2 pages and downloads as “contract-watermarked.pdf”; a 10-page report stamped “DRAFT” horizontally at 20% opacity and 36 pt at the top gets the same mark on all 10 pages; and a 5-page sample stamped “SAMPLE” diagonally at 50% opacity and 60 pt is unmistakable. The original file is never changed, your file never leaves your device, the tool is free, and there is no sign-in.
Frequently Asked Questions
What is a watermark PDF tool?
A watermark PDF tool stamps a word or phrase — “CONFIDENTIAL”, “DRAFT”, “SAMPLE” — across every page of a PDF in grey, semi-transparent letters. The mark says how the document should be handled, while the text underneath stays readable. The original file is never changed: the watermarked file is a new copy you download.
How do I add a watermark to a PDF?
Choose your PDF in the tool, type the watermark text, pick diagonal or horizontal, set the opacity and font size, then press “Add Watermark”. The tool stamps the same words on every page and gives you one download link for the watermarked file, named after your original — “contract.pdf” becomes “contract-watermarked.pdf”.
Can I watermark a PDF online for free?
Yes — this tool is completely free, with no sign-in and no limits on how often you use it. It runs entirely in your browser, so your file is never uploaded to a server, and there is no account or payment step at any point.
What does a diagonal watermark look like?
A diagonal watermark runs at -45 degrees across the page, from bottom-left to top-right, crossing the middle of the page. It is the classic “CONFIDENTIAL” look: visible wherever the reader looks, and hard to crop out of a screenshot because it spans the whole page. A horizontal watermark runs straight across instead.
Can I choose where the watermark sits on the page?
Yes — the position choice is Center (the default), Top, or Bottom. Center puts the mark across the middle of each page, which is the usual choice for a document-wide mark. Top or Bottom puts it near the edge, which suits a quieter status label like “DRAFT” that should not sit over the body text.
How do I make a watermark lighter or darker?
Use the opacity slider, which runs from 10% to 100% and starts at 30%. Lower opacity is fainter: at 10% the letters are a faint ghost, at 30% they are clearly visible but the page underneath shows through, and at 100% they are solid grey and will cover whatever sits behind them. For a document people still need to read, stay at 30% or below.
Does the watermark appear on every page?
Yes — the same text, in the same place, on every page of the PDF. A 2-page contract gets the mark on page 1 and page 2; a 10-page report gets it on all 10 pages. Watermarking never adds or removes pages, so the page count stays exactly the same as the original.
What text should I use as a watermark?
One or two short words work best: “CONFIDENTIAL” for a document that should not be shared, “DRAFT” for a version still being reviewed, “SAMPLE” for a preview that is not the finished file, or your company name. Keep it under 60 characters — a long sentence is hard to read diagonally and covers more of the page.
Can I remove a watermark from a PDF?
A watermark added by this tool is a visible layer of text over each page, and anyone with a PDF editor can delete that layer — it is a label, not a lock. The reliable way to undo it is to go back to your original file, which the tool never changes: the watermarked file is always a separate copy.
Do my files leave my computer when I watermark a PDF here?
No. The watermark is added entirely in your browser, on your own device — your PDF is never uploaded to a server, stored, or seen by anyone else. You can use the tool offline once the page has loaded, and closing the page removes the files from the tool.
What is the largest PDF I can watermark?
Files up to 50 MB can be watermarked here. The limit exists because the whole job runs in your browser: a larger file would use too much of your device’s memory and could freeze the page. If your file is over 50 MB, compress it first and try again, or split it into smaller parts.
Why does the tool say my PDF is password-protected?
Some PDFs are locked with a password, and the tool cannot open a locked file without it. Open the PDF with the password in your usual PDF reader, then save an unprotected copy and watermark that copy instead. If you do not know the password, the file cannot be watermarked here.