Add Text Watermark to PDF
Add Text Watermark to PDF draws the entered text—or WATERMARK fallback—on every page at 20% page width and 50% height, using 36-point Helvetica Bold, gray, −35° rotation, and 35% opacity. It does not repeat, center by text width, wrap, adapt to page rotation, add an image, or provide tamper evidence.
Runs locally — files stay on your deviceDoes the watermark secure or authenticate the PDF?
No. It is ordinary page content that can be edited or removed with capable software.
A visual watermark is an overlay, not cryptographic provenance
The added text becomes another content stream on each page. It can deter casual reuse but does not establish an unforgeable origin.
How it works
All pages are copied, Helvetica Bold is embedded, and one translucent diagonal drawText operation is added per page.
Key concepts
Placement is proportional only in x/y
Font size stays fixed across page sizes.
Existing content is not analyzed
The mark can collide or disappear visually.
When to use it
- Label review copies.
- Add a visible draft or confidential cue.
- Create a simple local overlay.
When not to use it
- Do not rely on it as DRM or certification.
- Do not expect automatic readability on all backgrounds.
- Do not use long multiline text.
Worked examples
Draft label
- Input
DRAFT- Expected output
One diagonal mark per page
Fixed gray styling is used.
Empty input
- Input
Blank- Expected output
WATERMARK
Fallback text applies.
Long phrase
- Input
A very long notice- Expected output
May extend outside the page
No wrapping or width fitting exists.
Common mistakes
Calling it tamper-proof
It is editable PDF content. Correction: Use signatures and controlled distribution separately.
Assuming centered text
x is fixed at 20% width, not true centering. Correction: Inspect output.
Using long strings
No fit calculation occurs. Correction: Keep text short.
Best practices
- Use concise labels.
- Inspect light and dark pages.
- Use digital signatures for authenticity requirements.
Related operations and differences
PDF Text Extraction
Choose PDF Text Extraction when you need to extract readable text from a PDF in your browser.; use Add Text Watermark to PDF specifically for text watermark.
Add Blank Page to PDF
Choose Add Blank Page to PDF when you need to append a custom-size blank page to a PDF.; use Add Text Watermark to PDF specifically for text watermark.
Add Page Numbers to PDF
Choose Add Page Numbers to PDF when you need to place centered page numbers on every page.; use Add Text Watermark to PDF specifically for text watermark.
Crop PDF Pages
Choose Crop PDF Pages when you need to set a custom crop box on every PDF page.; use Add Text Watermark to PDF specifically for text watermark.
Delete PDF Pages
Choose Delete PDF Pages when you need to remove selected pages from a PDF.; use Add Text Watermark to PDF specifically for text watermark.
Duplicate PDF Pages
Choose Duplicate PDF Pages when you need to insert a copy after every selected page.; use Add Text Watermark to PDF specifically for text watermark.
Limitations and privacy
- Fixed font, size, color, opacity, angle, and approximate placement.
- No image watermark, tiling, per-page selection, wrapping, fitting, tagging, or tamper protection.
- 80 MB limit.
The PDF is read and processed locally in this browser.
Frequently asked questions
Is it cryptographically secure?
No.
Can opacity be changed?
No.
Does it cover every page?
Yes.
Can an image be used?
No.