How Postal Codes Work Around the World
A postal code helps postal operators sort mail, but there is no single worldwide format. Countries choose different code patterns, address order, and rules about whether a code is required at all.
Postal code, postcode, or ZIP code?
Postal code and postcode are broad terms for codes used in postal addressing. ZIP Code is the United States Postal Service's name for the U.S. system; it is not a universal format that can be applied to every country.
The Universal Postal Union describes more than 200 address formats. A code may use digits, letters, or both, and the position of the code in an address varies by destination. Some countries do not require a postal code for every address, or do not use a system in the same way as countries with nationwide postcodes.
Build the address for the destination country
- Start with the recipient's full delivery address: Use the recipient's supplied spelling, building or unit details, street, locality, and any other fields required by the destination.
- Check whether a postal code is required: Do not invent a code for a country or address that does not use one. Confirm the code and its exact characters with the destination postal operator or a trusted local source.
- Keep the code as text: Do not strip leading zeroes, spaces, hyphens, or letters when the destination's format uses them. A postal code is an identifier, not a number to calculate with.
- Follow the destination's line order: Address components are ordered differently around the world. Follow the recipient's example and the postal operator or carrier's current instructions.
A lookup is not the same as address validation
A country-format reference can explain the shape of a postal code, while a postal-code search can return places associated with a code. Neither automatically confirms that a complete street address exists, that mail can be delivered there, or that the format is accepted by a particular carrier.
TheCodePlaza's international directory and U.S. ZIP lookup are reference tools. For a shipment, verify the complete address with the destination postal operator or the carrier handling the parcel.
Common mistakes with international addresses
- Treating every country as if it used a five-digit U.S. ZIP Code.
- Dropping leading zeroes or letters while copying a postcode.
- Placing the code on the wrong line because another country's format was used as a template.
- Assuming a matching code alone confirms a deliverable street address.
Common questions
Do all countries require a postal code?
No. Postal-code systems and their use differ by country. Check the destination's postal authority or the current addressing requirements before sending mail.
Is a ZIP Code the same thing as an international postal code?
ZIP Code is the name of the U.S. postal-code system. Other countries have their own formats, names, and address conventions.
Does finding a postal code prove an address is deliverable?
No. A code may cover a delivery area and does not by itself validate a street, building, unit, or current delivery service.
Sources and further reading
- Universal Postal Union: Addressing Solutions — Describes country-specific address components and formatting templates, and the diversity of international address formats.
- Universal Postal Union: General Addressing Issues — Lists country-level postcode requirements and notes that some countries do not use a postcode system or do not require one.
- TheCodePlaza: Data Sources and Methodology — Explains the site's reference data and the limits of its postal-code tools.