How to Add a Stamp to a PDF (Free, 4 Ways)
Updated 28 September 2026
You have a stamp as a PNG and a PDF that needs it. Here are four free ways to put one on the other — pick the one that matches the software you already have.
Method 1: Adobe Acrobat Reader (Windows & Mac, free)
- Open the PDF in Acrobat Reader.
- Choose Fill & Sign (in the right-hand panel or under All tools).
- Click Sign → Add signature, then choose Image and select your stamp PNG.
- Save it, then click the page where the stamp should go. Drag the corners to resize.
- Save the PDF. The stamp is now part of the document and is kept in future copies.
Acrobat remembers the image, so the next PDF takes two clicks. Menu names change a little between Acrobat versions, but the image option in Fill & Sign has been there for years.
Method 2: Preview on a Mac (built in)
- Open the stamp PNG in Preview, press ⌘A then ⌘C to copy it.
- Open the PDF in Preview and press ⌘V. The stamp appears in the middle of the page.
- Drag it into place and resize it from the corners.
- Choose File → Export as PDF to save a flattened copy.
Method 3: Microsoft Word
Useful when you're creating the document yourself. Insert the stamp as a picture, set Wrap Text → In Front of Text, drag it into place, then use File → Save As → PDF. Our Word guide has the details, including how to repeat the stamp on every page.
Method 4: Google Docs
Choose Insert → Image → Upload from computer, click the image and select In front of text, move it into position, then File → Download → PDF document.
Tips for a realistic result
- Use a transparent PNG, not a JPG — a JPG has a white box around the stamp.
- Lower the opacity to 80–90% in the stamp maker so the stamp looks pressed onto the paper and doesn't hide the text underneath.
- Keep the size realistic: a real round stamp is about 4 cm across. On an A4 or Letter page that's roughly a fifth of the page width.
- Tilt it a few degrees if your editor allows rotation — real stamps are rarely perfectly straight.
Can people remove the stamp again?
In Acrobat's Fill & Sign and in exported PDFs from Word or Google Docs, the stamp becomes part of the page. Someone with a PDF editor can still edit the file, so a stamp image is not tamper-proof. If you need proof that a document hasn't been changed, use a certificate-based digital signature — see digital stamp vs. electronic signature.
Frequently asked questions
Can I add a stamp to a PDF without Adobe?
Yes. On a Mac, Preview can paste an image onto a PDF. On any computer you can insert the stamp in Word or Google Docs and export to PDF.
Why does my stamp have a white background on the PDF?
The image is probably a JPG. Download the stamp as PNG from the stamp maker — PNG keeps the transparent background.
Popular templates
More guides
- How to Add a Stamp in Word (Every Page or Just One)
Put a stamp image in a Word document: insert it in front of text, keep the transparent background, repeat it on every page with the header, and export to PDF.
- Stamp Size Guide: Common Sizes in mm, Inches and Pixels
Standard rubber stamp sizes for round and rectangular stamps in mm and inches, plus how many pixels you need to print a digital stamp sharply.
- Company Stamp: What to Include and How to Make One
What belongs on a company stamp — name, legal form, address, contact details, registration or VAT number — with layout examples and when a stamp has legal weight.