Watermark PDF

Watermark a PDF without uploading it.

Stamp CONFIDENTIAL, DRAFT, or any custom text on every page of a PDF. Control size, opacity, angle, and placement, all in your browser with nothing uploaded.

A document sealed inside a Faraday cage. Your files stay fully private, on your device. A document sealed inside a Faraday cage. Your files stay fully private, on your device.

A document you're watermarking is a document you care about.

Adding a watermark is a signal. It says this document is confidential, or a draft, or not for distribution. Uploading that document to a third party to apply the stamp is a contradiction: you're protecting it by giving it to a stranger first.

The difference in one sentence

If you're stamping a document CONFIDENTIAL, the last thing you should do is upload it to a server to add the watermark.

KeptPDF applies watermarks entirely in your browser. Your document never touches a server. The stamp is baked directly into the PDF locally. Check the Network tab yourself while watermarking and your document never appears in a request.

How to watermark a PDF

Three steps, on your device. No account needed, and nothing gets uploaded.

1. Open your PDF

Drop the file onto the page. It loads in your browser without being sent anywhere.

2. Configure the watermark

Type your text (CONFIDENTIAL, DRAFT, your company name), adjust the opacity, choose the angle, and set the position on the page.

3. Download the watermarked PDF

Every page carries the stamp. Save the copy to share.

Your stamp. Your document. Never uploaded.

Custom text

Type any watermark text: CONFIDENTIAL, DRAFT, FOR REVIEW, your organization name, or anything else. Adjust font size to fit.

Opacity and angle control

Dial in a subtle diagonal watermark or a bold centered stamp. Adjust opacity so the watermark is visible without obscuring the content.

Stamps every page

The watermark is applied to all pages in one step. No need to repeat per-page.

No upload or account needed

Watermark free with no account, no daily limit. Pro ($29/month) supports larger files (hundreds of MB practical limit, browser memory dependent).

Other ways to protect your document

Questions, answered.

How do I add a watermark to a PDF?
Open KeptPDF's Watermark tool, drop in your PDF, type your watermark text, adjust the opacity and angle, and download. Free with no account, no daily limit.
Can I customize the watermark position and angle?
Yes. You can place the watermark centered diagonally (the classic look), center it horizontally, or adjust the angle and placement to match your document style. Opacity is also adjustable.
Will the watermark cover the text underneath?
It depends on the opacity you set. A low-opacity watermark is visible but doesn't interfere with reading. A high-opacity stamp may obscure content, so set it to match what you need.
Is my document uploaded to a server?
No. The watermark is applied in your browser. There's no server step, and your document never leaves your device.
Is the watermark permanent?
Yes. KeptPDF bakes the watermark into the PDF's content stream. It's not a removable annotation or overlay layer that can be stripped with a PDF editor.
Is it free?
Yes. It's free with no account, no daily limit. Pro ($29/month) supports larger files (hundreds of MB practical limit, browser memory dependent).

Watermark a PDF. Free, in your browser.

Open Watermark PDF