01
Password Strength Checker
Estimates password entropy and crack time, and identifies the specific weaknesses in what you…
TC Kimlik No Validator
Checks a Turkish TC Kimlik No against both of its check digit rules, which are unusual and catch different errors.
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In short
The Turkish identity number uses two rules rather than one weighted sum, and they are unlike anything else in this family. The tenth digit is (the sum of the 1st, 3rd, 5th, 7th and 9th digits, multiplied by seven, minus the sum of the 2nd, 4th, 6th and 8th) modulo 10. The eleventh is simply the sum of the first ten digits modulo 10. Together they catch every single-digit typo — verified over 3,000 generated cases — but only about 91% of adjacent transpositions, because the odd-and-even structure means swapping two digits of the same parity class can cancel out. A number never begins with zero. None of this proves the number was issued: only the Nüfus ve Vatandaşlık İşleri can say that.
How to use the TC Kimlik No Validator
- Paste the number — punctuation and spaces are ignored.
- Read the verdict and, where the number encodes anything, what it decodes to.
- Treat a pass as "typed correctly", not as "confirmed by the authority".
About the TC Kimlik No Validator
The Turkish identity number uses two rules rather than one weighted sum, and they are unlike anything else in this family. The tenth digit is (the sum of the 1st, 3rd, 5th, 7th and 9th digits, multiplied by seven, minus the sum of the 2nd, 4th, 6th and 8th) modulo 10. The eleventh is simply the sum of the first ten digits modulo 10. Together they catch every single-digit typo — verified over 3,000 generated cases — but only about 91% of adjacent transpositions, because the odd-and-even structure means swapping two digits of the same parity class can cancel out. A number never begins with zero. None of this proves the number was issued: only the Nüfus ve Vatandaşlık İşleri can say that.
What people use it for
- Catching a mistyped number in a form before it reaches a database.
- Cleaning an imported list and finding the rows that cannot be right.
- Understanding what the number encodes and what it does not.
Details
| Rules | Two, and they are different in kind rather than two passes of the same sum |
|---|---|
| 10th digit | ((odd positions × 7) − even positions) mod 10 |
| 11th digit | Sum of the first ten, mod 10 |
| Typo detection | 100% of single-digit errors; about 91% of adjacent transpositions |
| First digit | Never zero |
The two rules fail independently, so the page reports which one broke — that usually points at which half of the number was mistyped. Nothing you paste is transmitted — the check runs entirely in your browser.
Where this tool stops
Internal consistency only. It cannot confirm the number was issued or belongs to anyone in particular.
Frequently asked questions
Why does a swapped pair of digits sometimes still pass?
Because the tenth-digit rule treats odd and even positions differently, so swapping two digits that sit in the same parity class can leave both sums unchanged. Measured over 3,000 cases it catches about 91% of adjacent transpositions. Schemes built on the Verhoeff algorithm, like India's Aadhaar, catch all of them.
Is a TC Kimlik No linked to a date of birth?
No. Unlike Poland's PESEL or China's resident ID, it encodes nothing — it is a sequence with two check digits, which is a deliberate privacy choice.
Can I check whether the number is real?
Not offline. The checksum tells you the digits are consistent. Turkey provides an official verification service that confirms a number against a name and birth year; that is the only way to establish existence.
Is anything I paste sent anywhere?
No. The arithmetic runs in this browser tab and no request is made — open your Network tab and watch while you type. That matters more for an identity number than for almost anything else on this site, which is why there is no server side to this tool at all.
Does this replace an official check?
No, and it cannot. Every scheme here proves at most that the digits are internally consistent. Only the issuing authority can confirm a number exists, is active, and belongs to a particular person.
Is there a limit on how often I can use the TC Kimlik No Validator?
Free, unlimited, and no email address required. You can use it a hundred times a day and nothing changes.
Is the TC Kimlik No Validator safe to use with private information?
No. The TC Kimlik No Validator runs entirely in your browser using JavaScript. Nothing is transmitted, logged or stored, which you can verify yourself in the Network tab of your browser's developer tools.
Who is the TC Kimlik No Validator for?
The jobs it is built for: catching a mistyped number in a form before it reaches a database. Cleaning an imported list and finding the rows that cannot be right. Understanding what the number encodes and what it does not. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
Is there anything the TC Kimlik No Validator cannot do?
Internal consistency only. It cannot confirm the number was issued or belongs to anyone in particular. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What figures does the TC Kimlik No Validator work from?
Rules is Two, and they are different in kind rather than two passes of the same sum. 10th digit is ((odd positions × 7) − even positions) mod 10. 11th digit is Sum of the first ten, mod 10. These are printed on the page itself, so you do not have to take them on trust.
Will this work on a tablet?
Yes. The page is responsive and the page works in Chrome, Safari, Firefox, Edge and Samsung Internet on both Android and iOS. There is no app to install and nothing to sign into.
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