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Mofumi PDF

Timestamp PDF

Stamp the current (or a chosen) date and time onto PDF pages — perfect for “Received” and “Approved on” marks.

100% Private — files never leave your device
Upload PDFDrop files here or click to chooseAccepted: PDF Files never leave your device

About this tool

Timestamp PDF adds a clean, visible date and time stamp to every page or just the pages you choose. Pick where it goes on a 3×3 grid, the font, size, colour and opacity, and add an optional label such as “Received:” or “Approved on”. Thai text and Buddhist-era years (BBBB) are fully supported, so “รับเอกสารวันที่ 21 ตุลาคม 2569” works out of the box.

The format uses simple tokens: YYYY for the year, BBBB for the Buddhist year, MM and DD for month and day, MMMM or TTTT for the English or Thai month name, HH:mm:ss for the time and Z for the time-zone offset. Leave the date field empty to use the moment you press the button, or type a date to back-date a register stamp.

This is a visible stamp, drawn as real text into the page. It is not a cryptographic proof of time: trusted RFC 3161 timestamps need an online timestamp authority, and Mofumi PDF never sends your files or hashes anywhere. If you need legal proof of signing time, use Digital Sign PDF with your certificate.

Engines: pdf-lib · fontkit

How to use

  1. 1

    Upload the PDF you want to stamp.

  2. 2

    Choose the label, date format, position and style — leave the date empty to use “now”.

  3. 3

    Click Add timestamp and download the stamped PDF.

Use cases

  • Incoming mail register

    Mark scanned letters and invoices with the date and time they were received.

  • Approval marks

    Add “Approved on …” to purchase orders or contracts before filing them.

  • Version snapshots

    Stamp drafts with the print date so everyone knows which copy is current.

Frequently asked questions

Is this a legally trusted timestamp?

No. It is a visible stamp. A trusted RFC 3161 timestamp requires contacting an online timestamp authority, which this offline tool deliberately does not do.

Can I use the Thai calendar?

Yes. Use BBBB for the Buddhist-era year and TTTT for the Thai month name, for example “D TTTT BBBB”.

Can I stamp a past date?

Yes. Type a date such as 2026-10-21 14:30 in the date field; leave it empty to use the current time.

Will the stamp follow rotated pages?

Yes. The position is calculated as the page is displayed, so the stamp is upright even on rotated pages.

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