How to Add a CONFIDENTIAL or DRAFT Watermark to a PDF

The short answer

Open Add Watermark to PDF, drop your file, type the word you want (it starts as CONFIDENTIAL), adjust Opacity and Size, and click 💧 Add Watermark & Download. The text is placed diagonally across the centre of every page in grey, and you get a new file ending in _watermarked.pdf. Opacity between 15% and 25% keeps the page readable while the mark is still obvious.

What the tool does

• Adds your text to every page, centred and rotated 45 degrees.
• Uses a bold grey font, so it reads as a stamp rather than part of the content.
• Lets you set Opacity from 5% to 50% (default 18%) and Size from 20 pt to 100 pt (default 48 pt).
• Saves a new file and leaves the original unchanged.
• Processes the PDF in your browser, so the document is not uploaded.

Step by step

Open Add Watermark to PDF and drop your PDF, or click to choose it.

In Watermark text, replace CONFIDENTIAL with your word if needed: DRAFT, COPY, SAMPLE, or a short phrase.

Set Opacity. Start at the default 18%.

Set Size so the text crosses most of the page without running off it (see the table below).

Click 💧 Add Watermark & Download. The watermarked copy downloads as yourfile_watermarked.pdf.

Open the downloaded file and check a page with dense text and a page with images.

If you want to try different settings, change them and click the button again. Each click makes a fresh copy from the original file.

Choosing a size that fits the page

The watermark runs diagonally, so it has roughly the page's diagonal to fit into: about 1,031 points on an A4 page and about 1,001 points on US Letter. Using the same bold font the tool uses, we measured how wide common words are at different sizes:

Text	48 pt	72 pt	100 pt
CONFIDENTIAL	357 pt	536 pt	744 pt
DRAFT	163 pt	244 pt	339 pt
COPY	136 pt	204 pt	283 pt
DO NOT COPY	334 pt	501 pt	696 pt
FOR OFFICE USE ONLY	544 pt	815 pt	1,133 pt

What this means in practice:

• CONFIDENTIAL fits comfortably even at the maximum 100 pt. It covers about half of an A4 diagonal at 72 pt and nearly three-quarters at 100 pt.
• Short words like DRAFT or COPY look small at 48 pt. Push the size to 100 pt for a bold stamp.
• Long phrases like FOR OFFICE USE ONLY are about 1,133 pt wide at 100 pt, longer than an A4 diagonal, so the ends can run off the page. Keep long phrases to about 72 to 80 pt.

Choosing an opacity

Opacity	Effect	Good for
5% to 10%	Faint, easy to miss in print	Subtle branding on presentation copies
15% to 25%	Clearly visible, text underneath readable	Confidential reports, drafts, review copies
30% to 50%	Dominant, can make small text hard to read	Sample or specimen copies not meant for real use

Printers vary. If the document will be printed, print one test page; a faint watermark on screen can almost disappear on a light laser print.

Which word to use

• DRAFT: the content is not final and may change.
• CONFIDENTIAL: share only with the intended people.
• COPY: distinguishes a copy from the signed or original version.
• SAMPLE or SPECIMEN: shows layout without being a usable document.
• A name or company watermark helps trace who a copy was shared with, for example "Shared with Priya Sharma, 30 Oct 2026".

Limits and common problems

Use plain English characters

The tool uses a standard built-in PDF font that covers basic Latin letters, numbers and common punctuation. Characters outside that set, such as Hindi or other Indian scripts, the ₹ symbol or emoji, cannot be drawn with it. If you include them, the watermark is not applied and you will see the message "Could not watermark this PDF". Remove those characters and try again; for example, write "Rs" instead of the ₹ sign.

Password-protected PDFs

If the PDF is protected, the same error message can appear. Open it with the password in your PDF reader, save an unprotected copy, watermark that, and then protect the result with Lock PDF if needed.

One position and colour

The watermark is always grey, centred and at 45 degrees on every page. There are no options for colour, corner placement, an image logo or selected pages only. If you need a watermark on only some pages, split those pages out with Split PDF, watermark them, and merge the parts again with Merge PDF.

Watermark last

Make other changes first and watermark at the end. Fill in form fields, add signatures and reorder pages, then add the watermark, so the stamp sits on top of the finished content. If you plan to split the document into parts for different people, watermark each part separately with that person's name. Adding a password, if you need one, should be the very last step, because a protected file has to be unlocked again before any further edits.

What a watermark can and cannot do

A visible watermark is a clear signal: it tells everyone who opens or prints the file what status the document has, and a name watermark discourages people from forwarding it. It is drawn on the page as ordinary text, though, so someone with PDF editing software can often cover or remove it, and it does not stop anyone from opening or copying the file.

For stronger protection, combine methods:

• Watermark the file, then add an open password with Lock PDF.
• Share only the pages the recipient needs.
• Keep the unwatermarked original somewhere private.

Watermarking photos instead of documents? See How to Watermark Photos Online: Size, Opacity and Placement.