Add a Watermark to PDF

Enter a one-line label such as CONFIDENTIAL, DRAFT, COPY, or SAMPLE. Text uses the built-in Helvetica PDF font with an 8 to 96 point size, native color selection, real PDF opacity, and angle presets from -45 to 90 degrees.

The visible preview is a lightweight placement guide rather than a rendering of your document. The final text is measured with actual font metrics and written directly into the PDF without converting existing pages into images.

Use a static PNG for logos that need transparent pixels or a JPG/JPEG for an ordinary opaque image. Image width is set as a percentage of each visible PDF page while the original image aspect ratio is maintained automatically.

PNG transparency remains part of the embedded image, and the selected watermark opacity is applied in addition to that alpha data. The image is embedded once and reused across selected pages rather than duplicated for every page.

Apply one watermark to every page, only odd or even pages, or custom pages and ranges such as 1, 3, 5-7. Page numbers are one-based, duplicates are included once, and invalid or out-of-range selections are rejected before processing.

Nine positions cover each corner, edge center, and the visual center. Placement respects the visible CropBox and existing 0, 90, 180, or 270 degree page rotations without changing page geometry.

Opacity from 0 to 100 percent is supported. Values above zero are written as actual PDF transparency, while 0 percent adds no visible watermark layer. Rotated watermark bounds are included when centering or keeping edge placements inside their configured margin, so oversized settings are rejected instead of being intentionally clipped.

Existing text, vectors, and images are not rasterized, so watermarking does not intentionally reduce their quality. Each Apply starts from the original file to prevent stacked watermark layers, and all PDF and watermark-image processing stays local in your browser.