Watermark PDF

About the Watermark PDF

Mark a document clearly as a draft, a sample or confidential before it circulates. Type your watermark text, choose how faint it should be, and the tool stamps it diagonally across the centre of every page while leaving the underlying content readable.

How to use it

1. Choose a PDF.
2. Type the watermark text, for example DRAFT, SAMPLE or your company name.
3. Set the opacity — 15–25% is readable without hiding content.
4. Press Add watermark and download.

Tips and good to know

• Short words work best; long sentences get small to fit the page diagonal.
• A watermark discourages casual copying but is not security — anyone with an editor can remove it.
• For truly sensitive files, combine a watermark with restricted sharing.
• Keep the unwatermarked original safely stored for your own use.

About pdf tools

PDF is the closest thing the internet has to digital paper. A PDF file describes every page as a fixed canvas, which is why it looks the same on a phone, a laptop and a printer. That fixed layout is also why PDFs are awkward to edit: the format was designed to preserve a page, not to rearrange it.

Our PDF tools work directly on the page objects inside the file. Merging copies pages from several documents into a new one; splitting copies a chosen range into its own file. Nothing is re-rendered or re-typed, so text stays selectable and images keep their original quality. Everything happens inside your browser using the open-source pdf-lib library — your contracts, invoices and scans never travel to a server.

Merging and splitting are lossless operations: the tool copies the exact page objects, fonts and images, so quality and file size stay close to the originals. What browser tools cannot do well is convert a PDF back into an editable Word or Excel document, because a PDF stores text as positioned characters rather than paragraphs and tables. Any service that claims perfect conversion is reconstructing the layout by guesswork. When you need to edit, it is usually better to go back to the source file. Before sharing a merged PDF, open it once to check the page order, and remember that combining a signed page with other documents does not change the legal status of the signature.

Popular ways people use pdf tools

• Combining a scanned contract with its signed signature page before emailing it to the other party.
• Pulling a single chapter out of a long report so a colleague only receives the pages they need to review.
• Turning phone photos of receipts into one PDF for an expense claim or a tax return.
• Bundling several invoices for a month into one file for your bookkeeper or accountant.
• Extracting the relevant pages of a manual to print, rather than printing the whole document.

How we build and test our free tools

Every tool in this collection is built and tested by The Curator team. Before a tool is published we check it against known reference results — textbook loan schedules, standard test vectors for hashes, sample files for conversions — and we re-check it whenever browsers change. Each page explains the method so you can verify the answer yourself rather than take it on trust.

The tools run as JavaScript inside your browser tab. When you choose a file, your browser reads it from your disk into memory; the tool processes it and gives you the result as a download. No copy is sent to us or to anyone else, and nothing is kept after you close the tab. That is why these tools are safe for personal documents, and why they keep working on a slow or interrupted connection once the page has loaded.

The collection is free because it is supported by advertising on these guide pages. We never charge for a tool, never add watermarks and never sell what you type. If something doesn't work as described, or you would like a tool we don't have yet, please contact us — new tools are added in regular batches based on what readers ask for.

Frequently asked questions

Can the watermark be removed?

It is drawn onto the page, so it can't be toggled off in a normal viewer, but PDF editors can remove it.

Will it cover my text?

At low opacity the text underneath stays fully readable.

Are files uploaded?

No.

Is the Watermark PDF really free?

Yes. There is no account, no trial and no watermark. The Curator is supported by advertising on its guide pages, never by charging for tools or selling your data.

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