Argentina Postal Code Format: CPA and Four-Digit Codes

Argentina has two codes for the same place. The original code has four digits, such as 1425. The CPA (Código Postal Argentino) extends it into eight characters in the form letter, four digits, three letters, such as C1425ABC. Both are official and both are in use.

The four-digit code

The four-digit code is a numeric code that identifies a locality or a district of a city. Many people still know it by heart and use it on forms, in shops and in daily correspondence. It is not as precise as the CPA, so a single four-digit code may cover many streets.

The CPA structure

Part	Characters	Meaning
Province letter	1 letter	The province or the autonomous city
Numeric part	4 digits	The older four-digit code
Block letters	3 letters	A block face, meaning one side of a street segment

The first letter identifies the province. For example, C is used for the Autonomous City of Buenos Aires, and B for the Province of Buenos Aires. The four digits in the middle are the same as the older code, which is why a CPA can be shortened to the older form by dropping the letters. The three final letters pinpoint the street segment, so the CPA can sometimes distinguish between the two sides of a street.

Valid format examples

The values below are generic and show the shape only:

• Four-digit form: 1234
• CPA form: A1234BCD
• CPA in a form that separates the parts: A 1234 BCD

Common mistakes

• Treating the CPA as optional everywhere. Some forms require only four digits, others require the CPA. Read the field label.
• Dropping the leading letter. Without it, the code is the older style and cannot be validated as a CPA.
• Mixing letters and similar digits. Be careful with O and zero, or I and one.
• Using a code from a neighbouring locality. Many localities of the Buenos Aires metropolitan area have similar looking codes.
• Lower case. Letters are conventionally written in upper case; accept and convert them.

Which to use

Use the CPA where it is requested and you know it, and the four-digit code where that is what the form accepts. If you only have one, say which, because ambiguity is a common source of confusion. For lookup, see finding a postal code in Argentina. For the whole address, read Argentina address format and the country overview.