PDF Watermark

How do you add a watermark to a PDF?

Choose a PDF file or drag it into the tool, enter Text or select a preset, and check the live preview. Click Apply Watermark to create the result, then Download to save a separate PDF. For a logo, use + Add logo / image with a PNG or JPEG. Leave Text empty if you want only the image.

A watermark can label a document as a draft, identify a review copy or display an ownership notice. Start with a preset that matches that purpose, then inspect the mark against actual text, charts and scanned pages. The output is a PDF with added page content. The tool does not alter the source file on your device, and applying a watermark does not automatically download it.

Which settings do the watermark presets apply?

The eight presets change more than the wording: they set font size, weight, opacity, rotation, color, position and tiling. The table lists their configured values. These are starting settings rather than a guarantee of readability on every document; a large centered stamp and a repeated small stamp serve different purposes.

Built-in text watermark presets; all use Bold weight

Text	Font size	Opacity	Rotation	Placement
DRAFT	150pt	35%	-45°	Center, single
CONFIDENTIAL	36pt	30%	-45°	Dense tiling
DO NOT COPY	36pt	35%	-45°	Dense tiling
SAMPLE	150pt	30%	-45°	Center, single
APPROVED	80pt	25%	0°	Center, single
INTERNAL	40pt	25%	-45°	Normal tiling
REVIEW	120pt	30%	-45°	Center, single
FINAL	80pt	20%	0°	Bottom Center, single

Use Font size for text sizing and Opacity for transparency. The sliders allow 12–150pt text, 5–100% opacity and -90° to +90° rotation. At 0°, text is horizontal. Choose Helvetica, Times Roman or Courier and Regular or Bold. Color offers six swatches plus a custom color. Review the downloaded PDF before distributing it, especially when a mark crosses small print.

How do position, tiling and layers change the result?

Single placement offers nine positions from Top Left through Center to Bottom Right, with nudge controls for adjustment. Tiling repeats the mark across the page instead. Sparse, Normal and Dense change the repetition spacing; position offsets apply only to single placement. The engine calculates coordinates using each page's dimensions, so mixed page sizes receive their own placement calculations.

Above content draws the mark after the existing page content. Below content places it before the existing content in the PDF drawing order. An opaque background or scanned page image can hide a mark placed below it; an apparently white area is not necessarily transparent. Check that distinction before choosing a background watermark.

For text tiling, horizontal spacing is max(textWidth × 2, 180) points and vertical spacing is max(textHeight × 3, 140) points, multiplied by the density factor. Sparse uses 1.8, Normal uses 1 and Dense uses 0.5. The grid extends beyond the page with padding equal to half its larger dimension. These calculations describe spacing, not a fixed number of visible marks.

How is a logo sized and combined with text?

PNG and JPEG are the accepted image formats. Scale ranges from 5% to 100% and multiplies the image's own width and height, rather than a percentage of the page width. For example, a 400 × 200 image at 30% produces a 120 × 60 point watermark. Its final position is calculated from those scaled dimensions and the chosen placement.

Text and logo share position, offset, opacity, rotation, tiling density and layer. Their sizes are separate: Font size controls the text, while Scale controls the image. The engine draws the text first and then the image, so overlapping artwork can cover lettering. If you need custom typography or lettering outside the bundled font, prepare that lettering as a PNG or JPEG and add it as the image watermark.

How do page ranges and dynamic text work together?

All targets the entire document. Odd and Even follow the original page numbers, while Custom accepts individual numbers and inclusive ranges. In an eight-page PDF, 2-4, 6 selects four pages: 2, 3, 4 and 6. Duplicates are removed and selections are sorted. Reversed ranges, page zero and numbers beyond the document's page count are rejected.

Use Page {page} of {pages} to show original page numbering. On page 6 of that eight-page document, the text becomes Page 6 of 8, even though only four pages receive watermarks. {filename} inserts the source name without its PDF extension, and {date} inserts the local date in YYYY-MM-DD format. Unknown tokens remain unchanged. For dedicated numbering layouts, see PDF Page Numbers.

Are there file-size or daily watermark limits?

This editor has no daily task counter or fixed file-size cutoff in its PDF loading path. It reads one document at a time into memory, so the practical constraint is the memory available on your device. A large file can still fail to load or process. After downloading a result, choose Watermark another to start a different document.

What happens to fonts and document data in the browser?

The file is read as an ArrayBuffer and kept as PDF bytes in browser memory. The pdf-lib engine loads those bytes, draws text or images on selected pages and saves new PDF bytes. It adds PDF drawing content rather than converting every page into a screenshot. Processing large documents still depends on available device memory; the editor includes a memory warning rather than promising that every file will fit.

Standard fonts are used when their encoding supports the text. Otherwise, the interface retrieves a Regular or Bold Noto Sans font asset from this site and the engine embeds only a subset. Turkish, Greek and Cyrillic can use that fallback, including characters introduced through filename tokens. A font request is different from uploading the PDF: document bytes are passed to the local engine.

Does a visible watermark protect a PDF from changes?

A watermark communicates status or ownership through visible content. This operation does not encrypt the file, impose editing permissions or certify an audit trail. Tiling repeats the message across more areas, but it does not make the mark permanent or prove who received the document. Choose wording that explains handling expectations without treating it as access control.

For several separate documents, open Bulk PDF Watermark. Keep this single-document editor when you need to inspect placement and choose a custom page range. If you need to assemble documents before marking them, use Merge PDF first, then review page numbering against the combined file.