How to use it
- Drop your PDF contract or document into the box.
- Upload a picture of your seal (the white background is removed automatically) or try the sample seal.
- Keep “straddle seal” on and choose the edge, height and size. The preview shows each page’s slice.
- Optionally go to the signing page and drag your seal and signature into place, then download the stamped PDF.
Why PikStamp
- Real straddle sealThe seal is sliced into N strips for N pages, exactly like stamping across a fanned stack of paper.
- Long documentsSet “pages per seal” so 100-page contracts still get clearly visible slices.
- Drag & drop placementPut company seal, personal seal and signature anywhere on any page.
- Private by designEverything runs locally in your browser. Ideal for contracts and invoices.
What is a straddle seal?
A straddle seal (also called a cross-page seal, paging seal or perforation seal; 騎縫章 in Chinese, 契印/割印 in Japanese, 간인 in Korean) is a company stamp placed across the edges of all pages of a document. Each page carries only a slice of the seal, so the pages can only be verified as a complete set. It proves that no page has been removed or replaced.
Traditionally you fan out the printed pages and press the seal across the edges. PikStamp does the same digitally: it cuts your seal image into equal strips and places one strip on the edge of each page, so the printed stack lines up into one full seal.
When do you need one?
Contracts and agreements with several pages, tenders and bids, invoices with attachments, quotations, legal documents and any multi-page file that must not be altered. Many companies in China, Taiwan, Hong Kong, Japan and Korea require a straddle seal before a contract is accepted.
More free tools
Frequently asked questions
How do I add a straddle seal to a PDF?
Open PikStamp, drop in your PDF, upload your seal and keep “straddle seal” switched on. Choose the edge and height, then click “Download stamped PDF”. The seal is automatically split across every page.
How big should the straddle seal be?
A company seal is usually 3.8–4.2 cm wide. With many pages each slice gets thin, so for long documents set “pages per seal” to around 8–12; the seal is then repeated for each group of pages.
Is PikStamp really free?
Yes. All features are free with no sign-up and no watermark. The site is supported by ads.
Are my files uploaded to a server?
No. Your PDFs and stamp images are processed entirely inside your browser with JavaScript. They never leave your device, so it is safe for confidential contracts.
Is a digitally stamped PDF legally valid?
A stamped PDF is widely accepted for everyday business such as quotations, invoices and contract drafts. For legally binding signatures in some countries you may need a certified digital signature. If unsure, ask the other party or a lawyer.
Does it work on my phone?
Yes. PikStamp works in modern browsers on Windows, Mac, Android and iPhone.