# Watermark PDF > A free online tool that adds a text watermark (up to 100 Latin characters on one line, with opacity, angle, size and color) to every page of a PDF, once in the center or tiled across the page; it only adds watermarks. Watermark PDF files with a text mark on every page, free and without an account. The watermark is drawn on top of the page content, so use a low opacity to keep your text readable. Only Latin characters work: letters, digits and common punctuation. The tool adds a watermark only and does not remove one. ## Key facts - Input: one PDF up to 10 MB without an account (50 MB signed in), up to 100 pages (500 signed in); encrypted PDFs are refused. - Settings: the text, opacity 5% to 100%, angle -90 to 90 degrees, font size 8 to 300 pt, color, and one watermark in the center or a tiled pattern of at most 300 marks per page; the API also takes a page range. - The watermark is drawn on top of the page content, not behind it, and only Latin characters work: Chinese, Japanese, Korean, Cyrillic, emoji and line breaks are refused. - In our test the text CONFIDENTIAL with the default settings on a generated 6 page PDF of 51 KB gave a PDF of 43 KB with 6 marks; DRAFT tiled at 24 pt gave 53 KB and 450 marks; results vary with the file. - API: POST the PDF to https://api.aiipworld.com/v1/uploads, then POST https://api.aiipworld.com/v1/pdf-jobs with op pdf_watermark_text, the param text and the upload id, and poll GET /v1/jobs/:id. - Free without an account: 20 PDF jobs per day per visitor, no watermark of ours. Signed in, each job costs 1 credit, plus 1 credit for each started 20 MB of result beyond the first 20 MB (100 free credits every month). - Files are deleted automatically: 10 minutes after conversion without an account, 1 day with a free account. ## How it works 1. Upload the PDF you have the right to use. 2. Type your watermark text, up to 100 characters, on one line. 3. Set the opacity, angle, font size and color, or leave the defaults. 4. Choose one watermark in the center of each page, or a tiled pattern. 5. Run the job and download watermarked.pdf. ## Watermark PDF: how to add a watermark to your file You can add watermark to pdf files in a few steps. Open the tool and upload one PDF. The web tool adds the watermark to every page of that file and gives you a new PDF named watermarked.pdf. Your original file is not changed. If you want to know how to make watermark on pdf files for your own documents, the steps are short. This tool is for marking files you have the right to use. Type the text, adjust the settings, run the job and download the result. The same steps apply when you want to put watermark on pdf pages for a draft or a confidential copy. Do not upload a file you do not have the right to use, as the Acceptable Use Policy requires. - One PDF per job - Result name: watermarked.pdf ## Type the watermark text The "Watermark text" box takes one line of up to 100 characters. The text is set in Helvetica and is drawn on each page you mark. Use short labels such as CONFIDENTIAL or DRAFT, because long text is harder to read on a page. A pdf watermark made here is plain text that you type. The tool checks your characters in your browser before the upload starts. If a character cannot be drawn, the tool shows which one it is. Our server refuses those characters too. ## Opacity, angle, size and color The opacity slider runs from 5% to 100% in steps of 5, and the default is 25%. The angle runs from -90 to 90 degrees in steps of 5; the default is 45, which makes the text rise to the right. The font size runs from 8 to 300 pt, with 48 pt as the default. The color defaults to gray, #808080. The opacity is the same on every page. Results vary with the file and the page size, so run a test with your own document before you share the result. ## One watermark or a tiled watermark PDF pattern The default placement puts one watermark in the center of each page. The tiled option repeats the text across the page in a grid. The marks turn with your angle, and every other row is shifted by half a cell. A tiled pattern can draw at most 300 marks per page. If the font is small or the page is large, the spacing grows automatically to stay under that limit. In our test, a tiled DRAFT text at 24 pt on a generated 6 page PDF gave a 53 KB file with 450 marks, 75 on each page. ## The watermark sits on top of the Page The watermark is drawn over the page content, not behind it. A dark or high-opacity mark can hide the text under it. Start with the 25% default and raise it only if the mark is too faint. In our test, a CONFIDENTIAL watermark with default settings on a generated 6 page PDF of 51 KB gave a 43 KB file with 6 marks, one per page. These numbers are from generated test files, not real documents, so your results will vary. - Start with the default 25% opacity - Check the first page of the result before you share it ## Latin characters only The watermark text can use letters, digits and common punctuation in Latin script. Chinese, Japanese, Korean, Cyrillic, emoji and line breaks are not supported. In our tests, 社外秘, Секрет, a text with emoji and a text with a line break were all refused, and no file was made. If you need a non-Latin watermark, this tool cannot draw it. Use a Latin label in the watermark text instead. ## Limits: size, pages and credits Anonymous visitors can upload one PDF up to 10 MB and up to 100 pages. Signed-in users can upload up to 50 MB and 500 pages. The free web tool allows 20 jobs per day per visitor across the PDF tools, and 40 uploads per day per visitor without an account. Signed-in jobs cost 1 credit, plus 1 credit for each started 20 MB of the result beyond the first 20 MB. The web tool gives a signed-in job 60 seconds and an anonymous job 30 seconds. Failed and timed-out jobs are refunded in full. ## Encrypted and damaged files Encrypted PDFs are refused. This includes files with a password to open and files with permission restrictions, whatever their strength. The tool does not accept a password and makes no attempt to open or break the protection. A slightly damaged PDF is repaired automatically when possible, and the result panel tells you so. The setting "Repair a slightly damaged PDF automatically" is on by default. If you turn it off, a damaged file is refused. A file that cannot be repaired is also refused. ## Watermark PDF from code Use the API when you need to watermark a PDF from your own system. First, POST the raw file bytes to https://api.aiipworld.com/v1/uploads with Content-Type application/pdf. The answer contains an upload_id. Then POST to https://api.aiipworld.com/v1/pdf-jobs with the op pdf_watermark_text, your params and the upload_id in files. Send your API key as Authorization: Bearer or in the x-api-key header. Then poll GET /v1/jobs/:id until the job succeeds, fails or times out. The text parameter is required. The other parameters are opacity, angle, font_size, color, position (center or tile), pages and allow_repair. The page shows a ready cURL, Node and Python example built from your settings. See /docs/ for the general API. - Errors: 400 invalid_params, 413 file_too_large, 422 not_a_pdf, 404 upload_not_found, 402 insufficient_credits, 429 rate limited - Failed jobs can return encrypted_pdf, corrupt_pdf, too_many_pages, page_out_of_range or bad_params ## Privacy: what happens to your file Your file is sent to our server to make the result. The working copy of the upload is deleted as soon as the job ends, whether it succeeds or fails. We keep no history of your jobs. The result is deleted after 10 minutes in the free web tool, and the result panel shows how long it stays. Download links are short-lived, so save your file when the job finishes. Upload only files you have the right to use. ## Questions ### Can I watermark a PDF for free? Yes, you can watermark a PDF for free without an account. Anonymous visitors get 20 jobs per day across the PDF tools and must pass a human check for each upload. ### Can I add a watermark to only some pages? The web tool marks all pages of the file. The API has a pages option that marks only the pages you choose. ### How do I make a diagonal watermark? Set the angle slider to a value such as 45, which is the default and makes the text rise to the right. In the web tool, the angle runs from -90 to 90 in steps of 5. ### Can I use my logo or an image? No. The tool adds only a text watermark, typed on one line. It does not support logos or pictures. ### Can I write the watermark in Chinese, Japanese or Cyrillic? No. Only Latin characters work, and Chinese, Japanese, Korean and Cyrillic are refused with no file made. ### Will the watermark hide my text? It can. The watermark is drawn on top of the page content, so a high opacity can cover the text under it. Start with the 25% default and check the result. ### Can I remove a watermark with this tool? No, the tool only adds a text watermark. It does not remove watermarks from a file. ### Does adding a watermark reduce the quality? The watermark is added on top of your pages, and the original file is not changed. File size changes depend on the file: in our test on a generated 6 page PDF, a default watermark gave a 43 KB file from a 51 KB input. Results vary, so check your own document. ### Can I watermark a password-protected PDF? No. Encrypted PDFs are refused, and the tool does not accept a password or try to open the file. ### Can I watermark a PDF in my own code? Yes. Use the API: upload the file, create a pdf_watermark_text job with your text and settings, then poll the job until it finishes. The page shows ready cURL, Node and Python examples. ## Related - [Add Page Numbers to PDF](https://aiipworld.com/tools/add-page-numbers-to-pdf/index.md) - [Password Protect PDF](https://aiipworld.com/tools/protect-pdf/index.md) - [Merge PDF Files Online for Free](https://aiipworld.com/tools/merge-pdf/index.md) - [Reorder PDF Pages](https://aiipworld.com/tools/reorder-pdf-pages/index.md) - [Rotate PDF Online for Free](https://aiipworld.com/tools/rotate-pdf/index.md) Page: https://aiipworld.com/tools/watermark-pdf/