Home Taiwan National ID (身分證字號) Taiwan
Taiwan Taiwan National ID (身分證字號) validator
How the Taiwan National ID (身分證字號) format works
- Format
- 1 letter (location code) + 9 digits
- Example
- A123456789
Things to watch for
- The leading letter encodes the city/county where the ID was first issued and is converted to a 2-digit value via a lookup table (with irregular values for I, O, W, Z) before the weighted checksum is applied
- The digit right after the letter traditionally denoted sex (1/2 on standard cards); this validator checks the weighted-sum formula only and doesn't validate that digit's meaning
- A Taiwan National ID identifies a specific individual — this check runs entirely in your browser, so nothing you type is stored or transmitted
^[A-Z][0-9]{9}$Taiwan’s National ID (身分證字號) is the identifier the Ministry of the Interior issues to citizens, made up of 1 letter followed by 9 digits — for example A123456789 — and required for banking, voting, and most official paperwork. Unlike a purely numeric ID, the leading letter carries meaning: it’s a location code for the city or county where the holder’s household was first registered, and it feeds directly into the checksum rather than being decorative.
To calculate the check, that letter is converted to a 2-digit value through a lookup table — A is 10, B is 11, and so on — except that I, O, W, and Z sit outside the otherwise sequential pattern, because those counties were assigned codes later. Those 2 digits, followed by the 9 digits that make up the rest of the ID, give 11 values in total; each is multiplied by a fixed weight (1, 9, 8, 7, 6, 5, 4, 3, 2, 1, 1), and the sum of all 11 products must be a multiple of 10.
How this validator works
This tool converts the leading letter using the same lookup table the Ministry of the Interior uses, applies the weighted sum to all 11 resulting values, and confirms the total is a multiple of 10 — entirely in your browser. Nothing you type is sent to a server or stored.
What a pass doesn’t tell you
A pass confirms the letter and 9 digits are internally consistent with the checksum formula — not that the ID was ever issued, or that it currently belongs to a living, registered person. A Taiwan National ID identifies a specific individual, so treat any ID you check here with the same care as other personal ID data.
Scope: this page and tool cover Taiwan National ID format and checksum validation only — not Ministry of the Interior registration or identity verification.
Content last reviewed 2026-08-09.
Taiwan National ID (身分證字號) FAQ
What does the letter at the start of a Taiwan ID mean?
It's a location code showing which city or county the holder's household was first registered in. The Ministry of the Interior converts that letter into a 2-digit numeric value before the checksum is calculated, using a lookup table where the letters I, O, W, and Z break the otherwise A-to-Z sequence because those counties were added later.
Does the digit right after the letter reveal the holder's sex?
On standard cards, that digit has historically been 1 or 2 to indicate sex. This tool only verifies that the full weighted checksum formula holds — it doesn't check or interpret what that digit means.
Does a valid checksum confirm the ID was actually issued?
No. It confirms the letter and 9 digits are internally consistent with the Ministry of the Interior's formula — not that the ID was ever issued to a real person or that it's currently valid.