Thailand National ID Validator
Check the check digit of a 13-digit Thai national identification number with the official weighted algorithm. 100% local. Built for Thailand.
Batch check — paste many, one per line
Validate a Thai national ID
Enter a 13-digit Thai ID number to verify its check digit, read the registration category, and split out the registration office code. Registration status is not verifiable offline.
How the Thai 13-digit ID number works
Thailand's national identification number was introduced with the civil registration reform of 1984 and is administered by the Bureau of Registration Administration of the Department of Provincial Administration (DOPA), Ministry of Interior. It is printed on the ID card in five groups, and each group carries meaning.
Structure
| Group | Digits | Meaning |
|---|---|---|
| 1 | 1 | Person category, from 1 to 8 for Thai nationals and residents. Category 1 is a Thai national born after 1 January 1984 whose birth was registered in time; 3 is a person already in a house registration book before 1984; 6 to 8 cover non-Thai residents and naturalised citizens. The full list is in the FAQ. |
| 1017 | 2 to 5 | The registration office that issued the number: digits 2 and 3 are the province, digits 4 and 5 the district or municipality office. |
| 00230 78 | 6 to 12 | The person's sequence number within that office and category, printed as a group of five and a group of two. |
| 3 | 13 | The check digit, computed from the twelve digits before it. |
Worked example: 1-1017-00230-78-3
Each of the first twelve digits is multiplied by a weight that runs from 13 down to 2. The products are added, the total is divided by 11 and only the remainder is kept. The check digit is 11 minus that remainder; if the result is 10 or 11, only its last digit is used (so 10 becomes 0 and 11 becomes 1).
| Digit | 1 | 1 | 0 | 1 | 7 | 0 | 0 | 2 | 3 | 0 | 7 | 8 | Sum |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Weight | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | |
| Product | 13 | 12 | 0 | 10 | 63 | 0 | 0 | 12 | 15 | 0 | 21 | 16 | 162 |
The products add up to 162. Divided by 11 the remainder is 8, and 11 minus 8 is 3, which matches the 13th digit. Because every weight is different and 11 is a prime number, this check catches any single wrong digit and any two neighbouring digits that were swapped.
Official sources
Common mistakes and what the check digit cannot tell you
- Typing 12 or 14 digits: hyphens and spaces are fine, but the number must contain exactly 13 digits. The tool reports how many it found.
- A leading 0 is not issued to Thai nationals; it appears on certain cards for people without registered nationality status. The tool flags it so you can compare with the physical card.
- The registration office code tells you where the person was first registered, not where they were born or where they live today.
- A valid check digit does not prove the number is issued, current or belongs to the person presenting it. Identity verification requires the official DOPA registration system or the card's other security features.
- The laser code printed on the back of the card is a card-control number used by DOPA to track the card itself; it is not part of the ID number and is not checked here.
เลขประจำตัวประชาชน, Thailand's 13-digit national identification number, is issued by the Department of Provincial Administration and printed on every Thai ID card. The digits carry meaning: the first is a registration category, the four that follow identify the district registration office, and the last is a check digit.
To verify it, the first twelve digits are multiplied by descending weights from 13 down to 2 and summed; the check digit equals (11 − sum modulo 11) modulo 10. This tool recomputes the check digit locally in your browser, decodes the registration category, and splits out the office code so you can see which part of a number looks wrong.
Scope and limits: the check digit catches single-digit typos and most transposed pairs, but a well-formed number is not proof of issuance or identity — only the Department of Provincial Administration's own records can confirm that. A leading 0 or 9 is unusual on a real card and worth checking against the document itself. Everything you paste stays in your browser. Last verified: August 2026.
FAQ
What is the Thai national ID number?
Thailand’s 13-digit national identification number, issued by the Bureau of Registration Administration of the Department of Provincial Administration (DOPA). It is printed on the ID card in five groups, and the 13th digit is a check digit.
What does the first digit mean?
It is the person category: 1 = Thai national born after 1 January 1984 whose birth was registered in time; 2 = born after 1984 but registered late; 3 = Thai or foreign resident already in a house registration book before 1984; 4 = present before 1984 but not registered at the time; 5 = added later, for example after a census omission or for dual nationals; 6 = foreigner living in Thailand temporarily or without legal status; 7 = Thailand-born child of a category 6 parent; 8 = foreigner with permanent residence or naturalised Thai citizen.
What do digits 2 to 5 mean?
They identify the registration office that issued the number: digits 2 and 3 are the province code, digits 4 and 5 the district or municipal office within it. It shows where the person was first registered, not where they were born or live now.
How is the check digit calculated?
Multiply the first 12 digits by weights running from 13 down to 2, add the products, and divide by 11. The check digit is 11 minus the remainder; if that gives 10 or 11, only the last digit is used. For 1-1017-00230-78-3 the products add up to 162, the remainder is 8, and 11 minus 8 is 3, matching the last digit.
Does a valid check digit mean the ID is real?
No. It means the 13 digits are internally consistent, which rules out most typing errors. Whether the number is issued, current, and belongs to the person in front of you can only be confirmed through the official DOPA registration system or the physical card’s security features.
Why does the tool flag a number starting with 0 or 9?
Digit 0 is not issued to Thai nationals; it appears on certain documents for people without registered nationality status. Digit 9 is not a standard category. Both pass the arithmetic check if the last digit is right, so the tool marks them as unusual and asks you to compare with the card.
Is my number uploaded when I check it?
No. Validation runs entirely in your browser, including batch checks.
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