Taiwan National ID format validator. 1-letter region prefix + 9 digits with embedded check digit. Browser-only — your ID never leaves the page.
Taiwan National ID Format Validator (台灣身分證)
How to use
Enter the ID
1 letter (region of origin) + 9 digits. Example: A123456789.
Letter → 2-digit code
Each letter maps to a 2-digit code (A=10, B=11, ..., Z=33, with some skipped numbers).
Weighted sum
Apply weights [1,9,8,7,6,5,4,3,2,1,1] to the 2-digit letter code + 9 digits.
Mod 10 check
Sum must be divisible by 10 for VALID. Gender comes from the 1st digit (1=male, 2=female).
About the Taiwan National ID number
Taiwan's National ID Card is issued by the Ministry of the Interior (MOI). The number format is 1 letter + 9 digits. The leading letter encodes the region of original household registration, the first digit encodes gender (1=male, 2=female, 8/9=foreign UI), and the last digit is the checksum.
26 letters = 26 region codes
A=Taipei, B=Taichung, C=Keelung, D=Tainan, E=Kaohsiung, F=New Taipei, G=Yilan, H=Taoyuan, J=Hsinchu County, K=Miaoli, M=Nantou, N=Changhua, P=Yunlin, Q=Chiayi County, T=Pingtung, U=Hualien, V=Taitung, W=Kinmen, X=Penghu, Z=Lienchiang. Remaining letters (I/L/O/R/S/Y) correspond to merged former counties or special regions.
"The Taiwan ID is a 3-segment encoding: region + gender + checksum."
Practical use cases
Taiwan IDs are everywhere: online shopping signups, bank accounts, tax filings, NHI healthcare, exam registration, telco activation. A 5-second local check catches ~90% of mistypes (missing letter, swapped digit) before they cause real problems.
Privacy stance
This tool runs entirely in your browser; the ID is never uploaded, logged, or stored. Taiwan's Personal Data Protection Act (PDPA) treats national ID numbers as sensitive personal data — our zero-network design complies fully.
10 facts about the Taiwan National ID
Taiwan National IDs have been issued since 1947 — one of Asia's earliest mandatory ID systems.
The checksum algorithm is officially published by the MOI — fully verifiable offline.
The letter prefix reflects the region of first issuance — it doesn't change if you move later.
Letters I, O, R correspond to merged former counties (Taichung Cty, Hsinchu City, Tainan Cty) — still in active use.
The gender digit is the 1st digit after the letter — 1=male, 2=female, 8/9=foreign UI.
26 letters × 10⁹ ≈ 26 billion possible IDs; only ~24 million actively issued (Taiwan population).
From 2026, Taiwan rolls out the new "Digital ID Card (New eID)" — but the number format stays the same.
Foreign Alien Resident Cert (ARC) uses the same format but 1st digit = 8 or 9 instead of 1/2.
NT$2 trillion in annual electronic transactions rely on this 10-character ID for authentication.
Taiwan PDPA treats national ID as sensitive personal data — this tool's zero-network design fully complies.
Frequently Asked Questions
No. Validation runs entirely in your browser — your ID is never uploaded, logged, or stored.
No. It only means the format satisfies the checksum algorithm. Real authenticity requires verification via the MOI Household Registration Office.
The region of first issuance. E.g. A=Taipei, E=Kaohsiung, F=New Taipei. Even if you later move, the letter doesn't change.
Correspond to merged former counties (e.g. R=Tainan County, merged into Tainan City). These letters are still valid; just no new issuance.
Yes. Foreign Alien Resident Certificate (ARC) uses the same algorithm; only the 1st digit is 8 or 9 instead of 1/2.
Yes. The 1st digit: 1=male, 2=female. Taiwan is one of few countries encoding gender directly into the national ID.
No. Taiwan IDs do not encode birth date (unlike Mainland China). Age requires separate household register lookup.
No. The 2026 Digital ID Card (New eID) keeps the same number; only the physical card changes (chip-enabled).
This page validates one at a time for privacy. For bulk use, copy the JavaScript algorithm into your own code (no API required).
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Stored only in this browser — never sent to our servers.