The basics
A postal code is a short string of digits or letters that identifies a mail delivery area: a district of a city, a town, a cluster of villages, or sometimes a single large building. Postal operators use it to sort and route mail automatically, and almost every online form uses it to identify your area, estimate shipping, or verify an address.
ZIP code, postcode, PLZ, PIN: the same thing
Different countries name the same concept differently:
- ZIP code - United States ("Zone Improvement Plan", introduced 1963). Five digits, optionally +4 for a finer area.
- Postcode - United Kingdom, Australia, New Zealand, Netherlands. The UK's alphanumeric system (like SW1A) is one of the most precise in the world.
- PLZ (Postleitzahl) - Germany, Austria, Switzerland. Digits only.
- PIN code - India ("Postal Index Number"). Six digits covering the whole country.
- Postal code - Canada (alphanumeric, like K1A 0B1) and the generic international term.
Why one code can cover many places
In rural areas, a single code often serves several villages that share one delivery route. In dense cities the reverse is true: one city uses hundreds of codes, sometimes one per few streets. That is why our lookup lists every place a code covers, and every code a city uses.
Formats vary by country
Most systems are all-digit (5 digits is the most common worldwide), but several mix letters and digits for more precision. Each of our country pages shows the exact pattern, where N is a digit and A is a letter, plus the full code directory.
What postal codes are not
They are not exact addresses (they identify areas, not buildings), they are not fixed forever (operators add and retire codes as areas grow), and they are not globally unique: code 10115 exists in Germany and other countries. Always pair a code with its country.
Look one up
Use the free postal code lookup for any of 90+ countries, or start from a country directory. Developers can use the free JSON API.