Set up your input
Enter thirteen digits and run the check. Spaces and hyphens are removed before calculation.
Little helpers for test data
Thai ID checksum checker
Check the format and checksum of a Thai ID number privately in your browser. See the arithmetic without a registry lookup.
Results
Your results will appear here.
How to use
Review and adjust
Use the main button to see the result. Adjust your input and run it again. Processing stays in this browser.
Use the result
Copy the result into your test system. Where download buttons are shown, files are created from the current result in your browser. Inputs and outputs are not saved or uploaded.
Try these examples
Test input handling
Use 1234567890121 to see a weighted sum of 352, remainder 0 and final digit 1.
Test presentation and integration
Change the final digit to 3 to see a checksum mismatch. No government registry is consulted.
References and limits
checkDigit = (11 − (sum % 11)) % 10
Sample numbers may coincide with real numbers. A correct checksum or matching format does not prove issuance or identity.
Check digit arithmetic example (Thammasat University)