Writing Dates in Taiwan Official Documents (公文)

A Taiwan government letter dated 中華民國115年9月22日 was issued on 22 September 2026. Government correspondence and official documents (公文) date every letter in ROC years: add 1911 to the printed year.

The formal written form

Official documents — letters, orders, memos and notices issued by government agencies — use the most formal version of the ROC date, spelling out 中華民國 (Republic of China) before the year, followed by 年, 月 and 日.

Formula	Western year = ROC year + 1911
Example	中華民國115年9月22日 → 115 + 1911 = 2026 → 22 September 2026
Shorter form	民國115年9月22日 or simply 115年9月22日 — same date, less formal register

Check any official date with the ROC year converter, which also gives the formal written form if you need to produce one yourself.

What counts as a 公文

公文 (gongwen), usually translated "official document," refers broadly to any formal document a government agency produces in the course of its business — a letter to a citizen, an inter-agency memo, a formal order, or a public notice. Their structure, including how the date is written, is standardised rather than left to each agency's own style.

The legal basis

The format of official documents in Taiwan is governed by the Official Document Formats Act (公文程式條例). Article 6 of that Act requires that an official document "shall be dated with the year, month and day" — by long-standing convention, and consistent with how every other ROC-issued document is dated, that year is the ROC (Minguo) year. You can read the Act itself, in English, via the Laws & Regulations Database of the Republic of China, Ministry of Justice.

Reading the document reference number

Formal government correspondence typically carries a reference or dispatch number alongside the date, and that number commonly embeds the ROC year as part of its structure, together with the issuing agency's code and a sequence number. If you're trying to work out when a document was issued from its reference number alone, look for a component in the range of roughly 1 to 120 — that's very likely the ROC year, not a serial count.

Outside government correspondence

Businesses, associations and individuals in Taiwan often follow the same ROC convention for formal letters, contracts and invoices, particularly where a government agency is the recipient. Informal correspondence, and documents addressed to an overseas or non-Taiwanese recipient, more often use the Western calendar instead — there is no single rule that applies outside government documents themselves, so check the specific convention expected by whoever you're writing to.

This page explains the date format only. It is not legal advice on drafting official documents and is not affiliated with any government agency. For the current text of the governing law, consult the Ministry of Justice's Laws & Regulations Database directly.

Frequently asked questions

How is the date written on a Taiwan government letter?

In the formal ROC written form, typically 中華民國115年9月22日 ("Republic of China year 115, month 9, day 22"), which converts to 22 September 2026 by adding 1911 to the year.

What is a 公文?

公文 (gongwen) means "official document" — any formal document produced by a government agency in the course of official business, including letters, memos, orders and notices. Their format, including how dates are written, follows the Official Document Formats Act.

Is there a law that governs the date format on official documents?

Yes. The Official Document Formats Act (公文程式條例) sets out the required format of official documents in Taiwan. Article 6 requires that official documents be dated with the year, month and day; by long-standing convention this year is the ROC (Minguo) year.

Do private companies and individuals also date letters this way?

It varies. Correspondence with government agencies, and many formal Taiwanese business documents, follow the same ROC convention. Informal or international correspondence often uses the Western calendar instead, especially when addressed to a non-Taiwanese recipient.

Does the document number also encode the ROC year?

Many government document reference numbers include the ROC year as part of the file or dispatch number, alongside the issuing agency's code. Treat any number in that string that looks like a small year — in the range of roughly 1 to 120 — as a ROC year rather than a serial count.