Edit PDF

Add Watermark to PDF

Stamp diagonal text (e.g. “CONFIDENTIAL”) across every page.

PDF file

Choose a file to convert. It's processed locally — never uploaded. Tip: add several files to convert them all at once.

Settings

Output

Result appears here after you select

{ } Options

  • Text — any Latin text; the default is CONFIDENTIAL.
  • Angle — 45° by default; 0 is horizontal, negative values tilt the other way.
  • Opacity — 0.2 by default so the page stays readable; 1 is solid.
  • Font size — 48 pt by default. The text is Helvetica Bold in mid grey.
  • Tiled — repeats the text in a grid across the whole page instead of one centred line, which is harder to crop out.

{ } How it is applied

The watermark is drawn on top of the existing content of every page as real text — added to the page, not baked into pixels. That keeps the file small and the underlying text selectable, and it also means someone with a PDF editor can remove it. Treat it as a label, not as protection; for access control use Protect PDF.

{ } Image watermarks and letterheads

This tool stamps text only. To place a logo or a full letterhead on every page, make a one-page PDF of it and use Overlay PDF, which draws that PDF over each page at the opacity you choose.

{ } Limits

  • Latin characters only (Helvetica Bold has no Arabic, Cyrillic, CJK or Devanagari glyphs).
  • Password-protected PDFs must be unlocked first.

{ } How it works

Add Watermark to PDF works on the file you upload. Adjust the options, then select Process ▸ and it runs entirely in your browser — nothing is uploaded to a server — then shows the result in the Output panel.

Inputs

  • PDF file — upload a file (.pdf); it is read locally in your browser
  • Watermark text — a value (default: "CONFIDENTIAL")
  • Repeat across the page (tiled) — on/off toggle (default: off)
  • Opacity (0–1) — a value (default: "0.2")
  • Font size — a value (default: "48")
  • Angle — a value (default: "45")

Output

A downloadable PDF file — use the Download button in the Output panel.

{ } Common uses

  • Mark drafts as DRAFT or CONFIDENTIAL.
  • Tile a repeated watermark across sensitive documents.
  • Label copies before circulating them.

{ } Limitations

  • The watermark is text — a single diagonal line or a tiled repeat. An image cannot be used as the watermark.
  • A watermark is a deterrent, not security — it does not protect or encrypt the document.

{ } FAQ

Is my data uploaded to a server?

No. Everything runs locally in your browser — your files never leave your device.

Can I process more than one file at once?

Yes — add several files and they’re all processed and downloaded together as a ZIP.

Is this tool free?

Yes — it’s completely free and needs no sign-up.

Can someone remove the watermark?

It becomes part of the page content, but a determined user could cover or edit it. Use it to label documents, not to secure them.