How to spot a fake stamp on a document you have been sent
28 August 2026 ยท Estamplab
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If documents cross your desk carrying stamps, some of those stamps will eventually be fake. Not many, but the ones that matter tend to be the ones on the documents that matter: a bank letter, a certified copy of a qualification, a supplier's registration certificate, a landlord's authority to let.
A forged mark almost never fails on the design, because copying a design is trivial. It fails on the things around the design. This is where to look, and what to do when something is off.
This is the opposite of the page some stamp sites run. We do not help anybody make a mark in somebody else's name, and this site's terms say so. Knowing what a forgery looks like is what protects the people receiving documents.
The tells
1. A white box around the mark
The commonest by a distance, and the easiest to see. Zoom in on the stamp against a coloured area, a table rule or a line of text. If a faint rectangle of white sits behind it, the stamp was pasted in as a JPG, which cannot hold transparency.
That does not prove forgery on its own, because plenty of honest people make the same mistake, and we wrote the corrective for it in how to put a stamp on a PDF. But a genuine institution stamping its own outgoing documents usually does it properly, and a white box on a bank letter is worth a second look.
2. Resolution that does not match the page
Zoom to 400 per cent. Scanned text and a scanned stamp degrade together: same softness, same noise, same slight grey cast. A stamp that is crisp and clean sitting on soft scanned text was added after the scan. A stamp that is blocky and pixelated on otherwise sharp digital text was lifted from a screen capture of something else.
3. The identical impression twice
Real ink is never twice the same. Pressure varies, ink coverage varies, the angle varies, the paper takes it differently. Two impressions on the same document, or the same impression across several documents from different dates, that overlay pixel for pixel came from one image file used repeatedly.
This is the strongest single tell, and it is why serial numbers matter so much: a numbered mark cannot be reused without the reuse being visible.
4. Numbers that do not check out
Most official marks carry a number that exists in a register somewhere: a company registration number, a notary commission number, a professional licence number, a VAT number. All of these are verifiable, most of them in a public search that takes a minute.
Check the number, then check the name against it, then check the status. A number that belongs to a different entity, a dissolved company or a lapsed commission is not a design error.
5. An expiry that has passed
A notarial mark or a professional seal usually carries or accompanies an expiry. Check it against the date of the document, not against today. A commission that expired before the document was signed is decisive.
6. Wording that is nearly right
Forgers copy from a photograph, and photographs are lossy. Look for the wrong legal suffix (Ltd where the register says Limited, LLC where it says Inc), a misspelled town, a jurisdiction that does not issue that kind of mark, or a phrase translated slightly wrong.
7. Geometry that is subtly off
Text around a ring should follow the ring exactly. Warped or squashed lettering, a circle that is slightly oval, or a border whose stroke weight changes around the curve all suggest an image that was traced, stretched or rotated rather than generated.
8. Nothing under the stamp
A stamp is applied to a document, so on a scan the paper texture, the fold shadows and the printed lines carry through the gaps in the ink. If the area under the mark is unnaturally flat and clean, the mark was composited in.
How to verify properly
The tells above raise suspicion. These resolve it.
- Go to the source. Contact the issuing organisation on a number or address you looked up yourself, never one printed on the document you are checking. This single step defeats most document fraud, and skipping it is how most of it succeeds.
- Search the register. Company registries, professional bodies and notarial commissions are mostly searchable and mostly free.
- Ask for the original. A certified true copy is only as good as the certifier. If the mark is the whole basis of your trust, ask to see what it certifies.
- Check the file's own metadata. A PDF carries a creation date, a modification date and often the producing software. A "scanned" document produced by an image editor is worth a question.
- Ask about the serial. If the mark is numbered, ask the issuer to confirm that number against that document. An issuer who numbers their marks can answer immediately. One who cannot has told you something.
Making your own documents harder to forge
The same list read backwards is a checklist for your own outgoing paperwork.
Number your impressions. A stamp that carries a different serial on every document cannot be lifted from one and reused on another without the duplication being visible. This is the strongest control available and it costs nothing. On this site the serial increments on its own for signed-in accounts, so nobody has to remember a number, and it is the point of serial numbers on stamps.
Date the mark. A date on the stamp itself, not typed elsewhere, ties the impression to a moment.
Use a transparent PNG. No white box means one fewer thing that looks wrong to a careful reader, and it means your genuine documents do not resemble the forged ones.
Flatten it into the page. A stamp placed as a draggable annotation can be moved onto another document by anybody with a PDF editor. The stamp on a PDF tool writes it into the page content instead.
Sign the file where the stakes justify it. A cryptographic signature detects any later alteration to the document, which is a thing no visual mark can do.
Keep the design specific to you. A generic circle saying COMPANY SEAL is copied in five minutes. A mark carrying your registration number, your town and a serial is not worth copying, because every copy is checkable.
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Common questions
Is it illegal to make a fake stamp?
Making a mark that impersonates another organisation, a public body, a regulator or a professional you are not is forgery in essentially every jurisdiction, and using it on a document to induce somebody to act is fraud on top of that. Making a stamp with your own business's name on it is simply making a stamp.
Can you tell a digital stamp from a rubber one on a scan?
Often, but it proves nothing. Plenty of legitimate organisations stamp digitally, and increasingly most of them do. A digital mark is not a sign of forgery. A reused identical impression is.
What should I do if I think a stamp is fake?
Do not act on the document. Contact the issuing organisation directly, using contact details you found independently. Keep the original file rather than a re-saved copy, because its metadata is evidence. Where money or a legal position depends on it, take advice.
How can I make my own stamps harder to copy?
Number them, date them, keep them specific, and flatten them into the file. All four are covered above and all four are free.
Read next: serial numbers on stamps, and are digital stamps legal.