Home Thai National ID (เลขบัตรประชาชน) Thailand
Thailand Thai National ID (เลขบัตรประชาชน) validator
How the Thai National ID (เลขบัตรประชาชน) format works
- Format
- 13 digits: 12-digit body + 1 check digit
- Example
- 3100600445635
Things to watch for
- Weighted-sum mod-11 check digit (weights 13 down to 2) over the first 12 digits — format and checksum only, not proof the ID is currently issued or active
- The first digit denotes the holder's registration category (1-8 on real ID cards); this validator checks the mod-11 formula only and doesn't enforce that range
- A Thai National ID identifies a specific individual — this check runs entirely in your browser, so nothing you type is stored or transmitted
^[0-9]{13}$Thailand’s National ID (เลขบัตรประชาชน) is the 13-digit number the Department of Provincial Administration assigns to every citizen, printed on the national ID card and required for everything from opening a bank account to enrolling in school — for example 3100600445635. Its digits aren’t an arbitrary serial: the very first digit is a registration-category code (1 through 8) describing how the holder came to be registered, and the digits that follow carry further registration-area detail that this check digit doesn’t decode or validate.
That structure is also why validating it takes a specific formula rather than a generic checksum. The Department of Provincial Administration multiplies each of the first 12 digits by a descending weight — 13 down to 2 — sums the 12 results, reduces that sum modulo 11, subtracts the remainder from 11, and reduces the result modulo 10 to produce the check digit. A single mistyped or transposed digit almost always breaks this calculation.
How this validator works
This tool confirms the input is 13 digits, then runs the real weighted mod-11 calculation against the 13th digit — entirely in your browser. Nothing you type is transmitted or stored.
What a pass doesn’t tell you
A pass confirms the 13 digits satisfy the mod-11 formula — not that the ID was actually issued or is currently active, and it doesn’t confirm that the first digit falls within the official 1-8 category range. A Thai National ID identifies a specific individual, so treat any number you check here with the same care as other personal ID data.
Scope: this page and tool cover Thai National ID format and check-digit validation only — not Department of Provincial Administration registration or identity verification.
Content last reviewed 2026-08-09.
Thai National ID (เลขบัตรประชาชน) FAQ
What does the first digit of a Thai National ID mean?
It's a registration-category code, 1 through 8, showing broadly how and when the holder was first registered — for instance, at birth versus later in life. This tool checks the mod-11 check-digit formula only; it doesn't enforce or interpret the category value.
Why mod-11 instead of the mod-10 or Luhn checks other national IDs use?
Thailand's Department of Provincial Administration multiplies the first 12 digits by descending weights (13 down to 2), sums the results, and reduces that sum modulo 11 before converting it to the final check digit — a different formula from the mod-10 or Luhn checks other countries use, though it serves the same purpose.
Does a valid check digit mean the ID is currently active?
No. It confirms the 13 digits are internally consistent with the mod-11 formula — not that the ID was ever issued by the Department of Provincial Administration or that it's currently valid.