PDF Watermark

PDF PRIVACY WATERMARK

About this tool

Stamp every page — DRAFT, CONFIDENTIAL, your text

Add a text watermark (DRAFT, CONFIDENTIAL, your name…) to every page of a PDF. Color, size, opacity, rotation, position — all configurable.

RT-IMG-017 · Image & File

Drop a PDF here or click to choose Adds a text watermark across every page

No PDF loaded yet.

Watermark text

Position

Color

Font size (pt)

Opacity (25%)

Rotation (°)

Margin (pt)

💡 Diagonal preset ignores rotation + position settings and places the text centred at −45° — the classic "CONFIDENTIAL" stamp. Use any of the 9 anchor positions for other styles (e.g., top-right "DRAFT", bottom-center page-by-page brand stamp).

Drop a PDF to begin.

🔒 PDFs stay on your device. Watermarking happens entirely in your browser using the self-hosted pdf-lib library. Nothing is uploaded — verify in DevTools → Network.

How to watermark a PDF

Add your PDF

Drag your file onto the dropzone or click to choose. The watermark will be applied to every page.

Type the watermark text

Common choices: CONFIDENTIAL, DRAFT, COPY, SAMPLE, NOT FOR DISTRIBUTION, or your name/company for a personal stamp. Up to 200 characters.

Choose position

The Diagonal preset places the text centred at −45° — the classic "CONFIDENTIAL stamp" look. The 3×3 grid picks a fixed anchor (top-left, bottom-center, etc.) with optional rotation.

Fine-tune colour, size, opacity

Default is a 72pt grey watermark at 25% opacity — visible but doesn't overpower content. Pick any colour with the swatch or hex code. Slide opacity to make it bolder or fainter. Margin controls how far from the page edge fixed-position watermarks sit.

Apply and download

Click Apply watermark and download. The output saves as {original}-watermarked.pdf with the watermark drawn over every page. The original content stays selectable + searchable underneath.

PDF watermarks — visible stamps, semitransparent intent

A PDF watermark is a layer of text drawn on top of every page with a level of transparency that lets the underlying content remain readable. The watermark text travels with the document — it's part of the PDF, not a viewer overlay — so anyone opening the file in any reader sees the same stamp. The pages aren't re-rendered; the watermark is just additional drawing operations appended after the existing page content stream.

Watermark vs redaction vs encryption

It's worth being precise about what a watermark actually does. A watermark is a visible label intended for human readers — "this is a draft" or "this is confidential." It doesn't prevent anyone from reading the document, screenshotting it, or extracting the text. Redaction is the removal of specific content from the document. Encryption is access control — preventing the document from being opened without a password. Watermarking is the lightest-touch of the three: it signals intent without restricting access.

Watermarks are honour-system markers. They work on people who would respect "draft, do not circulate" anyway. For anything stronger, use access control plus redaction — not a label.

The APAC enterprise context

Watermarking is one of the most common document operations across Singapore's legal and financial sectors (every external counsel deliverable carries a CONFIDENTIAL stamp), Malaysia's government workflow (procurement-sensitive PDFs are watermarked before circulation), Indonesia's corporate sector (board paper deliveries to non-executive directors), Vietnam's and Hong Kong's outsourcing industries (client-bound deliverables stamped with the contractor's name), and Thailand's tourism / hospitality sectors (proposal documents stamped DRAFT pending approval). Across the region, the watermark is the proof-of-process that comes free with every operations workflow — visible, durable, and trivially defeated by anyone who really wants to.

What this tool does — and what it doesn't

This tool adds a text watermark across every page with full control over text, color, font size, opacity, rotation, and position. It respects each page's existing rotation so the watermark lands in the right visible orientation. What it does NOT do: add image watermarks (logos — coming in v2), apply different watermarks to different pages (use the Splitter to separate, watermark each, then Merger to recombine), or remove existing watermarks from a watermarked PDF (impossible in general — removing a watermark would require recovering the bytes underneath, which a flattened PDF doesn't preserve).

10 Things to Know About PDF Watermarks

A PDF watermark is just text drawn at the end of each page's content stream. The original page content sits beneath the watermark's drawing operations.

The PDF spec doesn't have a "watermark" object type — every watermarking tool just calls it that to distinguish from regular content. Internally it's identical to body text.

Opacity in PDFs is implemented via the ExtGState (graphics state) dictionary. pdf-lib uses it transparently — you set opacity 0-1 and it does the right thing.

The diagonal "CONFIDENTIAL" stamp is centred and rotated −45°. Rotation goes around the text's bottom-left corner unless you adjust the anchor — pdf-lib handles that for you.

Watermarks survive PDF concatenation: merging two watermarked PDFs preserves both watermarks per page. Use the Splitter + Watermark + Merger flow if you need a watermark on only some pages.

The Acrobat "Watermark" feature is implemented identically to manual drawText — there's no special "watermark layer" in PDF. Both produce the same output bytes.

Watermarks can be removed by anyone with PDF editing tools — they're not security features, they're presentation features. Don't rely on them for confidentiality.

The PDF/A archival standard ALLOWS watermarks. The output of this tool is PDF/A-compatible (subject to the input being PDF/A — watermarking alone doesn't add or remove that compliance).

Helvetica Bold (used by this tool) is one of the 14 "standard" PDF fonts — every PDF reader has it built in, so the watermark adds essentially zero bytes for font data.

A 50-page PDF with a watermark on every page typically grows by just a few hundred bytes. Watermarks are nearly free in storage terms.

FAQ

No. The pdf-lib library runs entirely in your browser. The PDF is read into memory, the watermark is drawn in memory, and saved straight back to your downloads. Open DevTools → Network and watch when you click Apply — there's no outbound traffic.
Not reliably. Once a watermark is drawn into the content stream, it's just another set of drawing operations alongside the original content. Removing it would require manually editing each page's content stream and you can't recover what was beneath. Keep an un-watermarked copy of every document you watermark.
Yes. The watermark is drawn ON TOP of the existing content. The original text, links, and form fields are all intact and remain searchable / selectable in any PDF reader.
In front. We draw the watermark text last in each page's content stream, so it appears on top of the existing page content. Standard semitransparent appearance lets the underlying text remain readable through it.
Not directly in this tool — every page gets the watermark. For selective watermarking, use the PDF Splitter to separate pages, watermark the subset, then use PDF Merger to recombine. Per-page watermark control is on the v2 roadmap.
Not in v1. Image watermarking (logos, signatures) is on the roadmap — it requires the user to upload the image, scale it, position it. For text watermarks (the most common case), this tool covers the full range of styling needs.
Some PDFs have non-zero base rotation (90°, 180°, 270°) baked into the page metadata — common with scanned documents. This tool reads the page rotation and draws the watermark in the VISIBLE orientation. If you see misalignment, the source PDF may have an unusual rotation value — try a different position preset.
Not yet — this version uses Helvetica Bold (a built-in PDF standard font). Custom font embedding is on the roadmap. For most watermark text, Helvetica Bold is the safe default — it renders identically in every PDF reader and adds zero bytes for font data.
No. Watermarks are visual labels, not security controls. They signal intent ("this is confidential, please treat it that way") but anyone with intent to ignore the watermark can — by screenshotting, extracting the text, or using a different tool to remove the watermark. For actual access control, use PDF encryption (password protection).
Yes on iOS Safari and Chrome on Android. The position grid wraps to a 3×3 touch target. Watermarking a 100-page PDF takes about a second on a phone — pdf-lib's text drawing is highly optimised.