PDF 水印

给 PDF 页面添加文字或图片水印

将 PDF 文件拖放到此处，或点击浏览

选择 PDF 文件

最大文件大小：128 MB

你的文件完全在浏览器中处理，不会上传到任何服务器。

用 Logo 给 PDF 加水印 — 全页品牌盖章

Stamp your company logo, brand mark, or signature graphic onto every page of a PDF — perfect for invoices, proposals, training materials, portfolio work, or any document you want to brand. Browser-side processing keeps your logo and PDFs private, with full control over size, position, and opacity.

100% FreeNo UploadNo Sign-upVector + PNG Watermarks

使用步骤

Upload PDF + Logo: Drag your PDF in, then drag your logo PNG (transparent background recommended). Our tool accepts PNG, JPG, SVG. For sharpest stamping use SVG or high-res PNG (at least 300px wide).
Position & Size: Drag the logo preview where you want it — corners (subtle, professional), center diagonal (assertive, anti-copy), or repeating tile (full coverage). Resize, rotate, and adjust opacity (10-50% is typical; 100% is fully opaque).
Apply: Click 'Watermark'. pdf-lib processes every page in your browser via WebAssembly. A 50-page document completes in under 5 seconds.
Download Branded PDF: Save the watermarked PDF. The logo is embedded as a flattened image layer on each page. Email it to clients, publish on your portal, or print — recipients see your brand on every page.

为什么选择此工具

100% Local Processing: Files are processed entirely in your browser using JavaScript — never uploaded to any server.
No Limits: No file count or file size restrictions. Process as many files as your device can handle.
No Sign-up: Free forever, no account needed, no email required. Open the page and start.
Private by Design: Nothing is sent to any server. Close the tab and your files are gone forever.

常见问题

Can I add my logo as a watermark to a PDF?

Yes — our PDF Watermark tool supports image watermarks including logos. Drop your PDF, drop your logo PNG (transparent background works best), drag it to your preferred position, adjust size and opacity, and save. The branded PDF is ready in seconds.

What logo format works best?

PNG with transparent background is ideal — it stamps cleanly without white boxes around the logo. SVG works for vector logos but renders to PNG during stamping (sharp at any size). JPG/PNG with backgrounds also work if you want the watermark to include the logo's background. For best print quality, use PNG at 2× the display size (e.g. 600px for a 300px display).

Where should the logo go for best effect?

Three common placements: (1) corner — small logo in bottom-right at 50-70% opacity (subtle, professional, used for proposals/invoices); (2) center diagonal — large logo across the page at 15-30% opacity (assertive, used for anti-copy brand protection); (3) tile — repeating pattern across the page (anti-copy strong). We support all three.

Can I use the same watermark on many PDFs?

Yes — our tool saves your watermark settings (logo + position + size + opacity) to browser localStorage for reuse. Apply the same brand stamp across invoices, proposals, and other documents with one click. Stored only on your device, never uploaded.

Will the watermark look good in print?

Yes — we use vector rendering via pdf-lib. The logo prints at the resolution you specify (150/200/300 DPI) without pixelation. Embed your logo at the highest resolution you have — output PDFs will scale it to the chosen size without quality loss.

Is my logo or PDF uploaded?

No — nothing leaves your device. Both your logo and your PDF are processed locally. For brand assets and confidential documents, this is the safest workflow. Even saved watermark presets stay in browser localStorage only.