What is a CEP and who assigns it?

CEP stands for Código de Endereçamento Postal — Brazil's national postal code system. It is administered exclusively by Correios (Empresa Brasileira de Correios e Telégrafos), the state-owned postal operator. Correios assigns a unique 8-digit CEP to every street segment, PO box, and large-volume receiver in Brazil. The system was introduced in 1972 as a 5-digit code and expanded to 8 digits in 1992 to accommodate the country's growth.

Does a CEP have a check digit like a CPF or CNPJ?

No. Unlike CPF (which uses two MOD-11 check digits) or CNPJ (which uses two similar weighted-sum check digits), the CEP has no built-in checksum. Its validity is determined entirely by format (exactly 8 digits) and whether the 5-digit prefix falls within a range that Correios has allocated to a geographic area. There is no arithmetic you can run on the 8 digits alone to confirm the CEP is "real" — only a live lookup against the Correios database can do that.

What does the 5-digit prefix encode?

The first 5 digits (the prefix) map to a geographic range that identifies the state and, for large states, the sub-region within that state. For example, prefixes 01000–09999 are assigned to the city of São Paulo, while 10000–19999 cover the São Paulo interior. Prefixes 90000–99999 are reserved for Rio Grande do Sul. This validator decodes your prefix against the full published Correios range table.

What does the 3-digit suffix encode?

The 3 digits after the hyphen refine the address type. A suffix of 000 designates a general area (district or locality) CEP — often used as a fallback when a street does not have its own individual CEP. Suffixes 001–899 are street-level CEPs assigned to specific street segments. Suffixes 900–959 are PO boxes (caixas postais). Suffixes 960–979 are assigned to organisations that receive very high mail volumes (large companies, government agencies). Suffixes 980–999 are Correios post offices themselves.

Why does this validator not return the full address?

A full address lookup requires querying the Correios database, which is a network call. This tool runs 100% offline in your browser — it can validate format and decode the prefix region from a static lookup table, but it cannot retrieve the street name, neighbourhood, or municipality for a given CEP without a network request. The Correios ViaCEP API (viacep.com.br) and the official Correios search portal (buscacepinter.correios.com.br) provide live address resolution.

Is a CEP starting with 0 valid?

Yes — São Paulo CEPs start from 01000, so CEPs beginning with 0 are valid as long as the full 5-digit prefix is 01000 or higher. Prefixes 00000–00999 (i.e. prefixes below 1000 when read as an integer) are unassigned by Correios and are therefore rejected by this validator.

Brazil CEP Validator

The CEP (Código de Endereçamento Postal) is Brazil’s 8-digit postal code, issued and maintained by Correios — the country’s national postal operator. Every address in Brazil has a CEP, from urban apartment blocks in São Paulo to remote villages in the Amazon basin. The code appears on utility bills, bank statements, e-commerce checkouts, government forms, and any application that needs to identify or route mail to a Brazilian address.

Validating a CEP in software is a surprisingly common task: payment gateways require it for address verification, logistics APIs route deliveries using it, and tax systems tie it to fiscal zones. This tool validates the format, decodes the geographic meaning of the 5-digit prefix, and classifies the 3-digit suffix — entirely offline, without querying any external service.

Structure of a CEP

A CEP is always 8 digits, written as NNNNN-NNN:

Part	Digits	Meaning
Prefix	First 5 digits	Geographic range — encodes state and sub-region
Suffix	Last 3 digits	Address type (street, PO box, post office, etc.)

The hyphen is a cosmetic separator only. Internally Correios stores and processes the raw 8-digit string without punctuation.

How the prefix encodes geography

Correios divides Brazil into contiguous numeric blocks, each assigned to a state or metropolitan sub-region. The blocks were allocated roughly from south-east to north, with the most densely populated areas (São Paulo, Rio de Janeiro) getting the widest ranges.

For example:

01000–09999 — São Paulo capital
20000–23799 — Rio de Janeiro capital
70000–73699 — Distrito Federal (Brasília)
90000–99999 — Rio Grande do Sul

Within a state, blocks are further divided by municipality and street segment. A prefix that falls in 80000–87999 is unambiguously in Paraná; one in 50000–56999 is in Pernambuco. The validator decodes this mapping from a static table that covers all 26 states plus the Distrito Federal.

How the suffix encodes address type

The 3 digits after the hyphen tell you what kind of delivery point the CEP represents:

Suffix range	Type
`000`	General area / district — fallback CEP for an entire locality
`001–899`	Street-level CEP — specific street segment or block
`900–959`	PO Box (caixa postal)
`960–979`	Large-volume receiver (empresa de grande porte)
`980–999`	Correios post office

A “street-level” CEP (001–899) is the most common type. A locality CEP (000) is typically used when a village or rural area does not have individual street CEPs — the single 000 code covers the whole settlement.

Worked example

CEP 01310-100 — Avenida Paulista, São Paulo:

Prefix: 01310 — falls in the range 01000–09999, which maps to São Paulo capital (SP), macro-region Sudeste.
Suffix: 100 — in the 001–899 range, so this is a street-level CEP assigned to a specific segment of Avenida Paulista.
Formatted output: 01310-100
Verdict: Valid format, prefix in a known Correios range.

A second example: 20040-020 — Avenida Rio Branco, Rio de Janeiro:

Prefix: 20040 — range 20000–23799, Rio de Janeiro capital (RJ), Sudeste.
Suffix: 020 — street-level address.
Verdict: Valid.

An invalid example: 00001-000:

Prefix: 00001 — integer value 1, below the minimum assigned prefix of 1000.
Verdict: Unassigned — Correios has never allocated this prefix.

What this validator does and does not do

It does: confirm the CEP has exactly 8 digits, that its prefix is not in the permanently unassigned 00000–00999 block, that the prefix matches a published Correios geographic range, and what the suffix type indicates.

It does not: resolve the CEP to a street address, municipality, or neighbourhood — that requires a live API call. For full address resolution, use the open ViaCEP API or the official Correios search portal.

Privacy

The entire validation runs in JavaScript in your browser tab. No CEP or any other data you enter is transmitted, logged, or stored anywhere. The geographic range table is bundled locally — there are no network requests.