How to use
- Choose the PDF to stamp.
- Upload a photo or scan of your stamp, or switch to a text stamp and type a word such as APPROVED or PAID.
- Enter the stamp width in millimetres, pick which pages to stamp and drag the stamp into place in the preview.
- Tick "Cross-page seal" if you need one, set its vertical position, then download the stamped PDF.
Options explained
- Remove white background
- A photographed stamp comes with the paper behind it. This turns the white or grey paper transparent and keeps only the ink. It switches off by itself for PNGs that already have a transparent background.
- Stamp red
- Recolours a dull or orange-looking photo to an even red while keeping the stamp's light and dark patches.
- Stamp width
- The real size in millimetres. Printed at 100%, the stamp comes out this wide.
- Most pages per stamp
- When the cross-page seal covers more pages than this, it is split into several groups, each with a whole stamp, sized as evenly as possible.
- Double-sided printing
- Even pages print on the back of each sheet, so the cross-page seal goes on odd pages only — the right edge of each sheet's front.
When to use it
Signing page of a contract. Choose “Last page”, drag the stamp over your company name and date, then tick “Cross-page seal” for all pages so no page in the middle can be swapped.
Tenders and long submissions. By default each cross-page seal covers at most 20 pages, so a 200-page bid gets 10 stamps. If the buyer specifies how many pages one stamp may cover, set “Most pages per stamp” to match.
Invoices, statements and drafts. Switch to a text stamp and type APPROVED, PAID, RECEIVED, COPY or VOID. You get a red boxed stamp you can place on any page.
Double-sided print runs. Tick “Double-sided printing” and the seal lands only on odd pages, so after printing each sheet has its strip on the front edge and no half-stamps on the back.
How the cross-page seal is cut
The stamp is divided into equal vertical strips. Page 1 gets the left-most strip, the next page the one beside it, and so on, each placed flush with the page’s right edge. For a 42 mm stamp:
| Pages sealed | Most pages per stamp | Stamps | Strip on each page |
|---|---|---|---|
| 3 | 20 | 1 | 14 mm |
| 10 | 20 | 1 | 4.2 mm |
| 50 | 20 | 3 (17, 16 and 17 pages) | about 2.5 mm |
| 50 | 10 | 5 (10 pages each) | 4.2 mm |
Groups are kept as even as possible, so you never end up with one or two pages carrying a stamp of their own. Strips under about 2 mm are hard to make out on paper; use fewer pages per stamp if you get there.
Getting a clean stamp image
- Stamp firmly on clean white paper and let the ink dry so it does not smudge.
- Photograph it straight on in even light, without your phone’s shadow. A flatbed scan is better still.
- Keep “Remove white background” ticked. Greyish paper is removed too, and “Stamp red” fixes dark or orange colours.
- Enter the real width. Measure your stamp with a ruler; Chinese company seals, for example, are usually 40–42 mm across.
A stamp PNG that already has a transparent background — such as an electronic copy supplied by your company — can be uploaded as it is. Background removal switches off, so pale parts of the stamp are kept.
Before you send the file
- Only use stamps you are authorised to use. This tool does not create stamps; it only places the image you provide.
- The stamp can be extracted. Inside the PDF the stamp is a separate image that anyone can pull out with a tool such as Extract Images from PDF. If that matters, convert the stamped PDF with PDF to JPG and rebuild it with JPG to PDF; the stamp becomes part of each page, but the text can no longer be selected or searched.
- When you need a real digital signature. E-signature platforms bind the signature to a certificate and reveal any later change to the file; an image stamp cannot do that. To see whether a PDF carries a digital signature and whether it was edited after signing, use Verify PDF Signature.
Frequently asked questions
Is a stamp added this way legally binding?
It is a picture of a stamp, not a certificate-based digital signature, so it does not prove who applied it or that the file was not changed afterwards. It works where the other side accepts scanned or stamped copies. For contracts that need a qualified or advanced electronic signature, use a signing service that issues digital certificates.
What is a cross-page seal?
Common in China, Taiwan, Korea and Japan, a cross-page seal (also called a paging seal) is stamped across the fanned-out edges of all pages at once, so each page carries a strip of the same stamp. Swapping or removing a page breaks the pattern.
Why does each page show only a thin strip?
The stamp is shared out across the pages, one strip each, so more pages mean narrower strips. The tool shows how many millimetres each page gets; if that is too thin, lower "Most pages per stamp" to use several stamps.
Why does page 1 get the left-most strip?
When the printed sheets are fanned out with page 1 on top and each page below shifted a little further right, the strips line up left to right into the full stamp.
Will the stamp hide the text underneath?
No. The stamp is multiplied onto the page, so text under the ink stays readable, as with a real stamp.
Is my stamp uploaded?
No. The stamp image and the PDF are processed in your browser and are gone when you close the page.
Privacy
This tool runs entirely in your browser. Your files and text are processed on your device and are never uploaded to our servers.