Drop your document into the zone below, pick CONFIDENTIAL, DRAFT, COPY or your own wording, or upload a logo. Click any page to open it full size and drag the mark exactly where you want it - wherever you drop it is where it lands on every page. Set the opacity, the angle and the size, choose whether it sits over the text or behind it, and stamp the whole document at once. Nothing is uploaded.
Your files are read by JavaScript running on your own machine. There is no upload, no queue, and no copy on our server to delete later.
Drag a card to reorder it, or use the arrows under each card. The order here is the order in the output. Each card is a preview of the finished page, so what you see is what the PDF will contain.
Esc close ← → move R rotate
Starting
This is your processor doing the work, so the time it takes depends on your machine and not on how many other people are on the site.
The tool above is ready to use. The guide below covers the part that decides whether your watermark does its job or just makes the document annoying - what opacity actually protects anything, why "behind the text" exists and when it is the only correct choice, the difference between a watermark and a redaction, and the plain truth about whether a watermark can be removed.
Two minutes, nothing to install, and no account needed for your first run. This PDF watermark tool executes inside the page you are reading, so all four steps happen on your own machine.
Click the drop zone above or drag the file anywhere onto this page. Every page appears as a tile with the watermark already drawn on it, so you can see the effect across the whole document rather than on one sample.
Pick one of the standard stamps such as CONFIDENTIAL, DRAFT, COPY or DO NOT COPY, or type your own. Switch to Logo or image and choose a file instead. A PNG with a transparent background keeps its transparency all the way into the PDF.
The tile opens the page at full size. Drag the watermark anywhere on it and it snaps to the thirds and to the center lines. Wherever you leave it is where it lands on every page, and the tiles behind the dialog follow along as you move it.
Between 15 and 30 percent reads as a watermark and not as damage. Choose whether the mark sits over the text or behind it, decide which pages get it, and press Add watermark. The text is drawn as real text, so it stays crisp at any zoom.
Everything in the rail is live. Move the opacity slider and forty tiles change together; switch from one mark to a tiled grid and the whole document fills with them. The preview is not an illustration of the output, it is the output drawn at a different size, because the position, the size and the angle are computed by the same code that writes the file.
A watermark is a labeling device. It changes how a document is read and how it gets treated, and it does nothing whatsoever to stop anybody copying, printing, forwarding or altering the file it is printed on. Being precise about that is the difference between using it well and relying on it for something it was never built to do.
If you need something gone rather than covered, this is the wrong tool. A black box drawn over a paragraph is a black box with the paragraph still underneath it, readable by anyone who copies the text out. That is a redaction failure that has ended careers. Use Redact PDF, which destroys the content rather than the view of it.
A watermark is drawing operations appended to a page, and there are exactly two places they can go. Which one you choose changes what the document looks like more than any other setting in the rail.
The mark is drawn after the existing content, so it paints on top of it. This is what everybody expects and it is right for text stamps: DRAFT at 25 percent across the middle of a page is unmistakable and still leaves the words legible underneath. It is achieved with a transparency setting instead of by blending, so the mark is a real object at a real opacity rather than a faded picture.
The mark is written as its own content stream and then moved to the front of the page, so it paints first and everything the document already had paints over it. This matters more than it sounds. A full page logo at 30 percent over a page of body text makes the text hard to read; the same logo behind the text is a background the document sits on, and the text is completely unaffected. For any image watermark that covers most of the page, behind the text is the correct choice and over it is not.
The mechanism matters because it is where implementations differ: the original page content is wrapped in a balanced graphics state pair first, so a document whose own content stream leaves the coordinate system in an odd condition cannot drag the watermark out of position with it. If the reordering fails on an unusual file, the mark stays on top and the run still completes. That is deliberate. A watermark in the wrong layer is a small problem, and a lost operation is a bigger one.
| Text watermark | Image watermark | |
|---|---|---|
| What is written | A font reference and a string, drawn at a size, colour, angle and opacity. | An embedded image stream, drawn into a rectangle at an opacity. |
| File size cost | A few hundred bytes for the whole document. The standard typefaces carry no font file at all. | The image once, however large it is, plus a few bytes per page. A 2 MB logo makes the PDF 2 MB bigger, not 2 MB per page. |
| At high zoom | Perfectly crisp at any magnification. It is text, drawn from outlines. | As sharp as the file you supplied and no sharper. Supply something at least 1000 px wide. |
| Transparency | Set by the opacity control alone. | A PNG alpha channel is preserved as a proper soft mask, then multiplied by the opacity control on top. |
| Searchability | The watermark text is selectable and searchable in the finished PDF, like any other text. | Nothing to search. It is a picture. |
One consequence of the text path is easy to miss and occasionally useful: the word CONFIDENTIAL stamped across your pages is real text, so Ctrl+F finds it. If you would rather it were not findable, use an image instead.
The size control is a percentage of the page width, not a point size. That is not laziness. A 48 point stamp that reads correctly on A4 turns into a smudge on an A0 drawing and runs clean off the edge of a receipt. Scale it as a proportion instead and a document with mixed page sizes gets a watermark that occupies the same share of every sheet, whether that sheet is a letter, an A3 foldout or a scanned till receipt. That is what makes it look deliberate.
Page rotation is handled the same way it is everywhere in this suite: the position you drag on screen is mapped back into the file coordinate system, and the mark itself is turned to compensate, so a page stored sideways gets its watermark where you put it rather than ninety degrees away from it.
Three numbers decide whether the result looks professional or looks like the document was damaged in transit. There are defensible ranges for all three.
| Range | Reads as | Use it for |
|---|---|---|
| 8 to 14 percent | A texture. Visible on screen, easy to miss on a printout, invisible on a fax. | Background logos on documents that are mostly read on screen. |
| 15 to 30 percent | A watermark. Unmistakable, and the text underneath is still comfortable to read. | Almost everything. This is the working range and 22 percent is the default for a reason. |
| 35 to 50 percent | A stamp. Impossible to ignore and it starts to compete with the content. | VOID, EXPIRED, and anything where the mark matters more than the document does. |
| Above 60 percent | Damage. | Nothing, unless the document is genuinely meant to be unusable. |
The single most common mistake is setting the opacity for your screen rather than for paper. A watermark at 12 percent that looks perfect on a bright monitor can vanish entirely on an office laser printer running in draft mode, and the whole point of the mark is that it survives the printout. If the document will be printed, test at 20 percent or higher.
Diagonal is conventional for a reason beyond aesthetics: a diagonal mark crosses every column of a page, so it cannot be cropped out of a screenshot of one paragraph. Flat is right for a logo in a corner, and for anything sitting in a header or footer area. Vertical is niche. It works well down the outer edge of a page and badly everywhere else.
The default of 60 percent of the page width puts a diagonal stamp comfortably across the middle without touching the margins. Going above about 85 percent on a diagonal mark means the corners run off the page, which occasionally looks intentional and usually looks like a mistake.
Tiling repeats the mark on a grid. It is the right answer for one specific case: a document you expect somebody to photograph, screenshot or partially copy, where a single central mark could simply be cropped away. Three across and four down at low opacity is a good starting point. On a normal internal document it is overkill and makes the pages tiring to read.
Print one page before you stamp two hundred. Stamp the first page only, print it on the printer that will actually be used, and look at the sheet under the light the document will be read in. Screen opacity and paper opacity are different numbers, and printing one sheet is the only reliable way to find out what yours are.
Switch the tool to Logo or image and choose a file. The image is decoded by your browser and embedded directly into the PDF, so it never touches a server any more than the document does.
The two arrangements that look right are opposites, and the middle ground rarely works:
A medium sized logo at medium opacity over the middle of the text is the arrangement that satisfies nobody: too heavy to ignore, too light to be a statement, and directly in the way of reading.
Yes. Anybody with the right software can strip a watermark out of a PDF, and it is not difficult, which is why nothing on this page will ever call the mark tamper-proof or describe it as protection. We would rather say that plainly than let you rely on something that does not hold.
A watermark is a drawing instruction inside the page content. It can be found and deleted by anything that can edit a content stream, which includes several commercial editors and a number of free command line tools. There is no version of this that is different, on any service, at any price: if a viewer can composite the mark onto the page, an editor can take it off again. Treat the stamp as a label on the document and never as a control over it.
What follows from that, practically:
And the case that runs the other way, since people arrive here looking for it: this tool cannot remove a watermark that is already in a document. Nothing here searches a page for marks it did not put there. A stamp somebody else applied is indistinguishable from the rest of the content by the time it reaches you.
The usual architecture for a free tool that adds a watermark to a PDF is an upload form, a queue, a command line utility on a server you do not control, and a temporary download link. Your document crossed the internet and was written to a hard disk somewhere you cannot audit. The irony deserves naming: the documents people watermark are the exact ones they have already decided are sensitive enough to need marking. Stamping CONFIDENTIAL on a file by uploading it to a stranger is not a security posture. It is the opposite of one.
No upload endpoint exists here, because no server-side step exists to feed. Your PDF and your logo are both opened with the browser File API, embedded by a PDF library running as JavaScript on your own processor, and the stamped document arrives as a Blob your browser downloads from itself. Both files exist on your disk and in your RAM. Nowhere else.
The single exception, stated because it is the only request that ever depends on what you typed: wording containing a character outside Western European Latin causes a font file to be fetched from this domain so it can be embedded in your document. That request carries the name of a font. Your document never leaves.
| Symptom | Cause | Fix |
|---|---|---|
| The mark is invisible in print | The opacity was set for a bright screen. Office printers in draft or toner-save mode lose light greys entirely. | Raise it to at least 20 percent and print one test page on the printer that will be used. |
| The document is hard to read now | A large mark is sitting over the text at high opacity. | Switch the layer to Behind the text, or drop the opacity, or make the mark smaller. For a full page logo, behind is nearly always right. |
| The logo has a white box around it | The image is a JPG, or a PNG that was saved without transparency. | Re-export the logo as a PNG with a transparent background. JPG has no alpha channel and never will. |
| The logo looks blurry | The source image is too small for the size it is being drawn at. | Supply at least 1000 px on the long edge. Nothing can add detail that was not in the file. |
| Characters came out as question marks | Wording contained a character outside Western European Latin and the font file could not be fetched, usually because of a blocker. | Allow this domain and run it again. The font request carries no document data. |
| The mark is in the wrong place on some pages | Those pages are a different size or are stored rotated. The mark is placed proportionally, so it follows each page. | This is correct behavior. Check those pages in the full size preview and move the mark to a position that works on both shapes. |
| The card says Locked | The document is encrypted with a password. | Open it in a reader with the password, save an unencrypted copy, and watermark that. |
| A signature warning appears afterwards | The document was digitally signed, and any modification invalidates a signature. | Watermark before signing. No tool can add a mark to a signed document without breaking the signature, and one claiming otherwise is not preserving it. |
A watermark is normally the last thing done to a document before it is sent somewhere it should not spread. These are the tools that go with it:
Drop the file into the zone above, choose a stamp such as CONFIDENTIAL or DRAFT or type your own wording, click any page to open it full size and drag the mark where you want it, then press Add watermark. It is free and there is no watermark of ours on the result. No account is needed for your first run: an anonymous visitor gets one operation per 12 hours, a free CartHacker account gets two, and Premium removes the counter.
Yes. Switch to Logo or image and choose a file. A PNG with a transparent background is what you want, because the alpha channel is preserved as a proper soft mask in the PDF and the shape of your logo becomes the shape of the mark. Supply at least 1000 pixels on the long edge, since an image watermark is only as sharp as the file behind it. WebP, AVIF, GIF, BMP and JPG all work as well.
Between 15 and 30 percent for almost everything, and 22 percent is the default. Below about 14 percent it reads as a texture and can disappear entirely on an office printer in toner-save mode. Above 35 percent it starts competing with the content, which is right for VOID or EXPIRED and wrong for a draft marker. The most common mistake is setting it for a bright screen and then discovering it is invisible on paper, so print one page before you commit.
Over the text for stamps such as DRAFT or CONFIDENTIAL, which need to be unmistakable. Behind the text for anything large, especially a full page logo, because the document then reads completely normally and the mark becomes stationery instead of an obstacle. That is the whole rule. The tool writes the mark as its own content stream and moves it to the front of the page when you choose behind, so the existing content paints over it.
Yes, by anybody with the right software, and it is not difficult. A watermark is a drawing instruction sitting inside the page content, so anything that can edit a content stream can find it and delete it, and that is equally true of every watermarking tool at every price including this one. Treat it as a label. It deters accidents and casual reuse, which is most of what actually goes wrong, and it stops nobody who is deliberately trying to remove it. If you need control instead of a signal, encrypt the document with a password and permissions.
No. Nothing here searches a page for marks it did not put there, and by the time a document reaches you, a stamp somebody else applied is indistinguishable from the rest of the page content. This tool adds watermarks; it does not find or strip them.
By default, yes, and you can narrow it. Which pages offers every page, odd only, even only, the first page only, the last page only, or a page range you type using the same grammar as the rest of the suite, so 2-, 14, 20-30 works. Every page tile above shows whether that page is getting a mark, so you can confirm the selection before you run it.
A text watermark adds a few hundred bytes to the whole document, because the standard PDF typefaces carry no font file. An image watermark embeds your picture once, however many pages it appears on, so a 2 MB logo makes the file about 2 MB bigger in total, not 2 MB per page. Nothing else in the document is recompressed or rebuilt.
Yes. A text watermark is drawn as real text, so it is selectable, searchable and comes out with any text extraction. That is usually harmless and occasionally useful, since it means a document stamped CONFIDENTIAL can be found by searching a folder full of files for the word. If you specifically want it not to be findable, use an image watermark instead.
No, neither of them. Both are opened with the browser File API and processed by JavaScript running on your own processor, and the finished PDF is produced as a file your browser downloads from itself. Load this page, disconnect from the internet entirely, and it still works. The only request that ever depends on your input is a font file fetch, and only when your wording contains a character outside Western European Latin.
Yes. Click any page tile and the page opens at full size, where you drag the mark to any position you like. It snaps to the thirds and to the center lines so a corner placement lands cleanly, and wherever you leave it is where it goes on every page. Position is stored as a proportion of the page, so it stays in the same relative place on a document with mixed page sizes.
Yes to both. A scan is just a page with a picture on it as far as the watermark is concerned, and the mark is drawn over or under that picture exactly as it would be over text. Rotated pages are handled by mapping the position you dragged back into the file coordinate system and turning the mark to compensate, so a page stored sideways gets its watermark where you put it rather than ninety degrees away.
All of these run the same way: your file is read by JavaScript on your own machine, the work happens on your processor, and the result is handed back to you as a download that never existed anywhere else.
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