What is a Uruguayan Cédula de Identidad?

The Cédula de Identidad (CI) is the national identity document issued by the Dirección Nacional de Identificación Civil (DNIC). It is used across government and private services, including BPS (social security), DGI (tax), and bank account openings. The number is 1–7 body digits followed by a single check digit.

How is the Uruguay CI check digit calculated?

The body is padded to 7 digits with leading zeros. Each digit is multiplied by the fixed weight at its position (weights 2, 9, 8, 7, 6, 3, 4 from left to right). The products are summed, and the check digit is (10 minus (sum mod 10)) mod 10. If the sum ends in 0, the check digit is 0.

What does a valid CI number look like?

A CI is commonly written as 1.234.567-2, where the body (up to 7 digits) is separated from the check digit by a dash. Leading zeros in the body are typically suppressed in display but must be re-added before the algorithm is applied.

Can the same CI be written different ways?

Yes. The body is sometimes shown without leading zeros (e.g. 123456) and sometimes with all seven digits (e.g. 0123456). Both represent the same person. This tool accepts any form and pads internally before validating.

Does this tool confirm the CI belongs to a real person?

No. It only verifies that the check digit is arithmetically consistent with the body using the DNIC/BPS modulo-10 algorithm. It never contacts any government database. A passing result means the number is well-formed, not that it is currently registered or active.

Is my CI sent anywhere?

Everything runs in JavaScript in your browser tab. The number you type is never sent to a server, logged, or stored anywhere.

Uruguay CI Validator

The Cédula de Identidad (CI) is the Uruguayan national identity document issued by the Dirección Nacional de Identificación Civil (DNIC). The same number is used by BPS (social security), DGI (tax authority), banks, and virtually every digital service in Uruguay. Like many Latin-American identity numbers, the CI ends in a check digit (dígito verificador) computed from the preceding body digits. This tool verifies that check digit using the official DNIC/BPS mod-10 weight algorithm, shows every step of the calculation in a transparent table, and suggests the correct digit when the one you entered is wrong.

It is purpose-built for developers validating form input, data-cleaning pipelines, or anyone who wants to understand exactly why a CI passes or fails.

How it works

The algorithm has four steps.

Step 1 — Pad the body to 7 digits. The CI body is 1–7 digits long. Before applying the weights it is zero-padded on the left to exactly 7 digits: 123456 becomes 0123456, 1234567 stays as-is.

Step 2 — Multiply by the weight series. Each of the 7 padded digits is multiplied by its fixed weight:

Position	0	1	2	3	4	5	6
Weight	2	9	8	7	6	3	4

Step 3 — Sum the products.

Step 4 — Derive the check digit.

DV = (10 − (sum mod 10)) mod 10

The final mod 10 wrapper handles the edge case where sum mod 10 = 0, which would otherwise yield 10; in that case the check digit is 0.

Worked example

Take the CI body 1234567:

Position	Digit	Weight	Product
0	1	2	2
1	2	9	18
2	3	8	24
3	4	7	28
4	5	6	30
5	6	3	18
6	7	4	28

Sum = 2 + 18 + 24 + 28 + 30 + 18 + 28 = 148

DV = (10 − (148 mod 10)) mod 10 = (10 − 8) mod 10 = 2

So the full CI is 1.234.567-2. If you enter 1.234.567-5 the tool marks it invalid and shows that the correct digit is 2.

Note: 1234567-2 is a demonstrably constructed example and does not correspond to any real CI number.

Formula note

The weight series [2, 9, 8, 7, 6, 3, 4] is the official DNIC/BPS sequence. It is not the same as the Chilean RUT mod-11 algorithm or the Brazilian CPF mod-11 algorithm, even though superficially similar structures appear in other Latin-American schemes. The key distinctions are: Uruguay uses modulo 10 (not 11), so there is no special K or X case, and the result is always a single decimal digit 0–9.

Frequently asked questions

Do I need to include the dash when typing? No. The tool strips everything that is not a digit, so 12345672, 1234567-2, and 1.234.567-2 are all accepted and produce the same result.

What if the body is fewer than 7 digits? Just enter the digits you have followed by the check digit. The tool pads the body to 7 internally before applying the algorithm. Short CIs (e.g. 123456-X) are common for older numbers.

Everything runs locally in your browser tab — no number is ever uploaded or stored.