ZIP code vs postal code
ZIP is the American name for a postal code; every country has its own format and its own rules.
United States
Five digits, optionally extended with four more (90210-1234). Assigned by the
USPS as delivery routes.
United Kingdom
Alphanumeric, usually two parts — outward code and inward code — such as SW1A 1AA.
The outward part can cover a few dozen addresses; the inward part narrows to a street or a side of
one.
Canada
Six characters alternating letter-digit, such as K1A 0B1. The first three identify
a forward sortation area (often a whole neighbourhood), the last three a local delivery unit.
India
Six digits — the PIN code. The first digit is the postal zone, the second the sub-zone, the third the sorting district, and the last three the individual post office.
Germany and much of Europe
Germany uses five digits (10115), France five, the Netherlands four plus two
letters, Switzerland four. Formats differ enough that forms should never assume a length.
Why it matters
When a form rejects your postal code, the cause is almost always a validation rule written for one country's format. This directory maps US ZIP codes; for Indian PIN codes and other countries, see the sister sites in the footer.
Frequently asked questions
Is ZIP code only used in the US?
ZIP is a USPS trademark for the US system. Other countries call the same concept a postcode, postal code, PIN code or CAP.
Can a postal code be shorter than five characters?
Yes — several countries use four digits or fewer, and some mix letters and digits.
Are postal codes assigned by street?
In most countries they cover a group of addresses or a delivery round, not a single street number.