CalConverters

Watermark PDF

Drop a PDF and stamp a text or logo watermark across the pages — set opacity, rotate it diagonally, or tile it. Everything runs locally — nothing is ever uploaded.

Files never leave your device

Drop a PDF to watermark, or click to browse

PDF

What This Tool Does

Add Watermark to PDF overlays text or an image on every page at the opacity, rotation, and scale you choose, then gives you back the updated file — without anything leaving your browser. Drop a PDF, add your text or logo, set the style, and download.

Watermarks can be text in any language (including accented characters), or a PNG/JPG image. They appear on top of the existing content without altering the underlying pages.

Tip: Watermarks are completely reversible — they exist only as an overlay layer, so you can remove them by simply not saving the result.

Text Watermarks in Any Language

Type or paste text for your watermark — Vietnamese, Chinese, Arabic, emoji, and all Unicode are supported. Control the font, size, opacity (transparency), diagonal rotation angle, and color (RGB or hex). The text tiles across all pages at once.

Image Watermarks — Logos and Signatures

Upload a PNG or JPG image to use as a watermark instead. Place it diagonally, set its opacity and scale, and it repeats across every page.

Tiling and Transparency

Configure whether the watermark tiles (repeats) across the page or appears once. Adjust the opacity from fully transparent to fully opaque so the underlying PDF content shows through.

Nothing You Drop In Ever Leaves Your Device

The preview is rendered in your browser and the watermark is applied by a WebAssembly module loaded into the same tab. Your PDF is read, previewed, and rebuilt on your device with no upload step.

Related Tools

To add a visible signature image, use Sign PDF. To add page numbers (ASCII numerals only), try Add Page Numbers.

Frequently asked questions

Can I watermark with text in Vietnamese or other languages?
Yes. Text watermarks support all languages and accents. Type or paste your text directly — Vietnamese, Chinese, Arabic, emoji, and all Unicode are supported. Use Page Numbers if you need only ASCII numerals.
Can I use an image as a watermark instead of text?
Yes. You can upload a logo, signature, or any image to use as a watermark instead of text. Set its opacity, size, and rotation just like text.
Does the watermark change the PDF content?
No. A watermark is an overlay layer on top of the existing pages — it does not alter, recompress, or re-render the underlying text or images. To remove it, simply don't save the result.
Is my PDF uploaded anywhere?
No. The preview is rendered locally in your browser and the watermark is applied by a WebAssembly module loaded into the same tab. Your file is read and rebuilt entirely on your device — it is never sent to a server.