Watermark PDF: free online, fast and secure
A watermark tells readers a document is a draft, confidential or belongs to you, and discourages copying. This tool adds a text watermark to every page of a PDF.
Choose the text, colour, size and opacity, and a diagonal, centred, bottom or tiled layout. The watermark is drawn into the PDF, so it appears in every viewer and when printed.
How to use Watermark PDF
- Upload the PDF. Choose your document.
- Design the watermark. Type the text and set colour, size, opacity and layout.
- Apply. Download the watermarked PDF.
Why use ConvertKaro Watermark PDF? Free, fast and secure
Many online tools upload your file to a remote server and make you wait. ConvertKaro is different.
100% Free
Use Watermark PDF completely free, every day. No credit card, no “pro” version and no daily cap on files.
Fast results
No waiting for uploads to finish. The work happens on your device the moment you add a file, which makes it noticeably faster than server-based tools.
Secure and private
Your files never leave your device. ConvertKaro does not upload, store or look at your documents and photos, which makes it safe for ID cards, bank statements and private pictures.
No signup, no watermark
You do not need to sign up or log in, and your output is clean, without any logo or branding.
Works on every device
Nothing to install: it runs in any modern browser on phones, tablets and computers.
Diagonal or tiled
Classic diagonal stamp for drafts, or a repeating tile for maximum protection.
ConvertKaro vs other online converters
| ConvertKaro | Typical online tool | |
|---|---|---|
| Price | Free forever, every feature | Free trial, then paid plans |
| Your files | Stay on your device | Uploaded to a server |
| Signup | Not needed | Often required |
| Watermark or ads on result | Never | Common on free plans |
| Speed | Instant, no upload wait | Depends on upload speed |
| Daily limits | None | Usually limited |
Common uses for Watermark PDF
- Marking drafts and review copies
- Protecting confidential reports
- Branding quotations and catalogues
- Sharing sample documents
- Marking copies of ID proofs “For bank KYC only”
Tips for the best results
- 20–30% opacity keeps the text underneath readable.
- Write the purpose on ID copies, for example “For XYZ Bank KYC only”.
- Use Protect PDF as well to stop editing.
- For images, use Add Watermark to Image.
Good to know
There are two kinds of PDFs: digital PDFs created from Word, Excel or a website, which contain selectable text, and scanned PDFs, which are just photos of paper pages. Tools that edit pages, like Watermark PDF, work with both. Tools that read text work only with digital PDFs. If you can select a word in your PDF viewer, your file has a text layer.
| Price | Free, no limits |
|---|---|
| Processing | On your device, no upload |
| Signup | Not required |
| Watermark | None |
| Works on | Android, iPhone, Windows, Mac, Linux |
| Category | PDF tools |
How Watermark PDF keeps your PDF documents private
When you add a file to Watermark PDF, it is opened with your browser’s own engine, processed in memory and offered back to you as a download. ConvertKaro never receives a copy. This is why the tool is fast even on 4G, why there is no daily limit, and why it is safe for confidential PDF documents like ID proofs, bank documents, contracts and family photos.
Using Watermark PDF on your phone
On a phone, open this page in Chrome or Safari, tap the main button and pick files from your gallery, Files app or Google Drive. Results download straight to your phone, usually into the Downloads folder or Files app. You can also add this page to your home screen for one-tap access next time.
Who uses Watermark PDF?
You do not need any technical knowledge to use it. It is popular with:
- Students submitting assignments, certificates and mark sheets
- Job seekers sending resumes and documents
- Accountants and office teams handling invoices and statements
- Small businesses preparing quotations, bills and catalogues
- Anyone filling government, bank or insurance forms online
Supported input: PDF files of any size and page count, including scanned PDFs.
Frequently asked questions
Can the watermark be removed?
It is drawn into the page content. Combining it with password protection makes removal much harder.
Can I use Hindi text?
PDF standard fonts support English letters, numbers and symbols only.
Does it work on every page?
Yes. The watermark is added to all pages.
Is Watermark PDF really free?
Yes, completely free. You can use it as many times as you want, and every option on the page is included at no cost.
Is it safe to use Watermark PDF online?
Yes. Your files are processed inside your own browser and are never uploaded to our servers, so nobody else can see them.
Does Watermark PDF work on mobile?
Yes, the tool is built mobile-first. Open this page on your phone, add your files and download the result directly.
Is there a file size limit in Watermark PDF?
There is no fixed limit set by us because files are not uploaded. Very large files depend on your device’s memory; most phones handle files of 100 MB or more without problems.
Will ConvertKaro add a watermark or ask me to sign up?
No. There is no watermark, no login and no email required. Your downloaded file is exactly your result.
Does Watermark PDF work offline?
Once this page has finished loading, the tool keeps working even if your internet connection drops, because all processing happens on your device.
Related free tools
Explore more free tools that work the same way, privately in your browser: Protect PDF, Add Page Numbers to PDF, Add Watermark to Image, Sign PDF, Flatten PDF.