understand what changes with the new model that comes into force this month

With the growing demand for opening companies and the imminent exhaustion of available combinations for new registrations, the Federal Revenue Service began to adopt, this July, the alphanumeric National Register of Legal Entities (CNPJ), a new format for identifying legal entities in the country.

A. Companies that already have a CNPJ will not need to change their registrations and will continue to normally use the current number.

The current model, made up of 14 exclusively numeric digits, offers around 100 million possible combinations. According to the federal agency, the accelerated increase in the number of registered companies led to the need to expand this capacity. Today, the CNPJ has more than 60 million registrations.

The solution was to allow the use of letters and numbers in the first 12 characters of the CNPJ. The last two digits, responsible for the Check Digit (DV), remain exclusively numeric.

The Revenue’s expectation is that the demand for new registrations will increase even further with the implementation of the Tax Reform, which foresees the use of the CNPJ as a unique identifier for companies, gradually replacing state and municipal registrations.

Opening process does not change

Despite the change in number format, the business opening process will remain the same. Entrepreneurs will continue to follow the current procedures for obtaining the CNPJ, through the National Network for the Simplification of Registration and Legalization of Companies and Businesses (Redesim), whose systems have already been adapted to receive the new standard.

It will also not be necessary for existing companies to make any registration updates or replace their digital certificates.

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Companies will need to adapt systems

Although the Federal Revenue has informed that public systems will be prepared to recognize both numeric and alphanumeric CNPJs, companies that use their own systems or software for issuing invoices, financial management, payroll and tax control will need to check whether these platforms accept the new format.

According to Luidg Quitete, accountant and founder of Sapiência Contábil, the main change will occur precisely in the technological infrastructure of companies.

— In practice, it will be necessary to review processes and systems that treat the CNPJ only as a numeric field. The accounting routine does not change, but software, spreadsheets, integrations and records will need to accept letters and numbers — he explains.

The expert recommends that companies contact their software suppliers now to confirm whether the systems are ready to operate with the new standard. The guidance is especially valid for those using old or internally developed systems, which may require additional adjustments. If these adaptations are not made, there is a risk of operational failures.

— If a system continues to accept only numerical CNPJs, there may be rejections in the issuance of tax documents, registration inconsistencies, problems in the transmission of ancillary obligations and difficulties in exchanging information with public bodies and commercial partners — he warns.

The accountant highlights that large companies can face greater challenges due to the high number of integrations between different systems. Small and medium-sized companies tend to suffer more if they use outdated software or have little technological support.

In many cases, adaptation costs will be limited to updates made available by suppliers. Companies that use customized systems may need to invest in development, testing and approvals.

Firms will need to adhere to the new model in the future

At this first stage, companies that were already registered before the implementation of the new model will not need to adapt. However, the lawyer and accountant at Bergamini Advogados, Adriano Vitor dos Santos, warns that in the future businesses will need to migrate to the alphanumeric format.

— The Federal Revenue predicts that, after the initial implementation of the alphanumeric CNPJ, from July 2026, a gradual process of converting existing CNPJs to the new alphanumeric standard will begin. This migration must occur in a staggered manner, according to a schedule defined by the Federal Revenue Service, considering criteria such as size, type of company and economic activity — he says.

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The main recommendation for business owners is to prepare in advance. Júlia Castellari, lawyer from the Corporate Law team at Peluso, Guaritá, Borges and Rezende, advises that companies check with suppliers of management systems and issuance of invoices to see if they are already planning to update to the new CNPJ format. It also recommends carrying out tests before alphanumeric CNPJs go into operation, training teams on how to coexist between the old and new models and following the official guidelines from the Federal Revenue Service.

The lawyer also warns of possible scams. According to her, businesspeople should be wary of contacts, messages or emails of unknown origin that use the change in CNPJ as a justification for requesting payments, sensitive information or registration updates.

Check Digit Calculation

As already explained by the Revenue, the Verification Digit (DV), used to validate the authenticity of the CNPJ, will continue to be calculated using the mathematical method of Module 11, but will also consider the letters present in the new format.

This conversion will be done based on the ASCII table, which assigns a number to each letter, number and symbol. After identifying the ASCII code of the character, the Federal Revenue determines that the value 48 be subtracted.

In the example of CNPJ 12.ABC.345/01DE, the conversion looks like this:

A → ASCII code 65 → 17 (65 – 48)

B → ASCII code 66 → 18 (66 – 48)

C → ASCII code 67 → 19 (67 – 48)

D → ASCII code 68 → 20 (68 – 48)

E → ASCII code 69 → 21 (69 – 48)

After this step, letters are treated as numbers. Thus, the CNPJ used in the calculation becomes:

1 2 17 18 19 3 4 5 0 1 20 21

Each of these values ​​is multiplied by a sequence of weights defined by the Federal Revenue Service. When calculating the first check digit, the weights used are 5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3 and 2.

In the example, multiplications generate a sum of 459. This result is divided by 11 and only the remainder of the division is considered, which is 8. As the remainder is different from 0 or 1, the first check digit is calculated by doing 11 – 8, arriving at the number 3.

Then, this first digit is incorporated at the end of the sequence and the entire process is repeated, now using a new sequence of weights (6, 5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3 and 2).

The new sum is 424. The remainder of division by 11 is 6 and, again, the rule 11 – remainder applies, resulting in 5.

This way, the CNPJ in the example is: 12.ABC.345/01DE-35

Despite the inclusion of letters, the validation logic remains practically the same. The only new feature is the conversion of alphabetic characters into numeric values ​​before applying the Module 11 calculation.

To facilitate implementation, the agency will also make calculation routines available in different programming languages ​​for companies and developers to adapt their systems.