Turkish ID Number (TCKN) Validation

Instantly check whether a Turkish ID number (TCKN) is algorithmically valid.

The number is never sent to a server; the check runs entirely in your browser.
    Generate a number for software testing
    Generates a random number that follows the algorithm; it isn't meant to belong to a real person. Use it only in test environments.

    How does the TCKN validation algorithm work?

    The Turkish ID Number (TCKN) is an 11-digit number generated according to a specific mathematical rule. The first digit can never be 0. The 10th digit is calculated as the remainder, mod 10, of (7 times the sum of the odd-position digits — 1st, 3rd, 5th, 7th, 9th — among the first 9 digits) minus (the sum of the even-position digits — 2nd, 4th, 6th, 8th). The 11th digit is the remainder, mod 10, of the sum of the first 10 digits. Thanks to these two check digits, the odds of a random or made-up 11-digit number matching a real TCKN format are very low — which makes this useful for catching typos in form validation.

    Validation ≠ proof of identity

    There's a critical distinction here: this tool only checks whether the number matches a valid TCKN format algorithmically — it does NOT prove that the number belongs to a real, living person or that it hasn't been stolen. Whether an ID actually belongs to a real citizen can only be confirmed through the official identity verification services of Turkey's General Directorate of Population and Citizenship Affairs (NVİ) — for example, a lookup combining name, surname and birth year through e-Devlet (Turkey's e-government portal). Do not use this tool to "verify" someone's identity or to generate a fake ID.

    When is this useful?

    Legitimate uses include instantly checking whether a TCKN entered into a form or database contains a typo, generating algorithmically valid test data that doesn't belong to a real person while testing software (with the "Generate Test Number" button below), or confirming that a number read from a scanned/OCR'd document was read correctly.

    The number you enter matters especially because it's sensitive personal data: this page works without making any network requests, the number never leaves your browser, and it is never sent to OpenMoon's servers.

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    Frequently Asked Questions

    No. It only checks whether the number follows the official algorithm rules. Verifying that an ID matches a real person can only be done through Turkey's official NVİ (Population Registry) services.

    Yes. The number you enter never leaves the page; it isn't sent to any server or service. The check algorithm runs entirely inside your browser — you can even disconnect from the internet and try it.

    The number must have 11 digits and the first digit can't be 0. The 10th digit must equal the remainder, mod 10, of (7 × the sum of odd-position digits among the first 9) minus (the sum of even-position digits). The 11th digit is the remainder, mod 10, of the sum of the first 10 digits.

    Using real people's ID numbers while developing or testing software is both unnecessary and risky. The "Generate Test Number" button creates a randomly generated number that follows the algorithm rules — the odds of it belonging to a real person are vanishingly small; it cannot and should not be used to create a fake identity.

    Usually, yes — if a real 11-digit TCKN fails the algorithm check, it suggests a digit was entered incorrectly. But keep in mind that passing the algorithm doesn't mean a number is actually in use either; this is only a format check.

    No. The page doesn't write to localStorage, cookies, or any server; the number you enter exists only in your browser's memory while you're on the page, and disappears when you close or refresh it.

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