PDF透かし
PDFページにテキストまたは画像の透かしを追加
ブラウザ内で完全に処理されます。ファイルのアップロードはありません。
使い方
アップロード
ファイルをドロップ
処理
ブラウザで処理
ダウンロード
結果を保存
よくある質問
- How do I add a watermark to a PDF?
- Drop your PDF onto the page. Choose text or image watermark. For text, type your watermark text and customise the font, size, colour, and rotation. For image, upload a PNG or JPG. Set opacity and position, then apply to all pages.
- Can I position the watermark exactly where I want?
- Yes. Choose from preset positions (centre, corners, edges) or drag the watermark in the live preview to position it exactly. The same position applies to every page.
- Is my PDF uploaded to a server?
- No. Watermarking runs entirely in your browser using pdf-lib. Your file and watermark image never leave your device.
- Can I use a transparent PNG as the watermark?
- Yes. PNG transparency is preserved, so logos with transparent backgrounds blend cleanly with the PDF content. You can also adjust the watermark's opacity independently.
- Is this tool free?
- Yes — fully free with no account required.
- Does it work on mobile?
- Yes. The watermark tool works in any modern mobile browser. The drag-to-position preview works with touch.
- Can I add a watermark behind the content instead of on top?
- Yes. Choose between 'over' (in front of the page content) and 'under' (behind the page content). Under-mode is useful for subtle background watermarks that don't obscure text.