Postcode Format Checker
This page answers one question: does this look like the format the country uses? It does not — and cannot — tell you whether the postcode exists. That distinction matters, because a tool that shouts "invalid" at a correct address sends people off to break something that was working.
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Two problems that need different amounts of work
A spacing problem is batch-fixable. SW1A1AA is accepted by most
systems, but the United Kingdom writes it SW1A 1AA, and the two do not match each
other when anything compares addresses exactly — so the same customer arrives looking like two.
That is a find-and-replace.
A code that does not fit the pattern needs a human. It might be a typo, or it might be a genuinely unusual code this dataset does not cover. For 98 countries this page links the country's own postal lookup so you can settle it at the source instead of trusting us.
91 countries have no postcodes at all
In those places, a value in the postcode field is itself the bug — usually a default, a copied row, or a checkout form that made the field mandatory everywhere. This is the check nobody thinks to run, and it explains a surprising share of failed international deliveries.
Where the patterns come from, and what that means
They come from the address metadata that Chrome and Android use to validate addresses — widely deployed and maintained, but not the postal authorities themselves. The authoritative per-country tables sit behind a paid Universal Postal Union service, which this project does not have and does not pretend to have.
So every pattern here is checked against that dataset's own example postcodes before being carried, a mismatch is reported as a warning rather than an error, and the country's official lookup is offered wherever one is published. Those three choices are what an honest version of this tool looks like when it cannot be the final word.
Every check this tool runs (7 rules)
PC-M01 Does not match the usual format
The value does not match the pattern this country normally uses. That is a strong hint, not a verdict: this tool checks format against a widely deployed dataset, not against the postal authority’s own register, so a genuinely valid but unusual code could land here. Where the country publishes an official lookup, it is linked so you can settle it properly.
Fix: Check the code against the country’s postal lookup before changing anything.
Source: Patterns come from the libaddressinput metadata that Chrome and Android use for address validation, not from the postal authorities themselves — those sit behind a paid Universal Postal Union service. Every pattern is checked against that dataset’s own example postcodes before it is carried here, and where a country publishes an official lookup this tool links to it rather than pronouncing on validity.
PC-S01 Right code, wrong spacing or case
The characters are right but the presentation is not — a missing space, a stray hyphen, or lower case. Postal systems generally cope, but exact-match deduplication and address comparison do not, so the same address arrives looking like two.
Fix: Use the canonical form shown here.
Source: Patterns come from the libaddressinput metadata that Chrome and Android use for address validation, not from the postal authorities themselves — those sit behind a paid Universal Postal Union service. Every pattern is checked against that dataset’s own example postcodes before it is carried here, and where a country publishes an official lookup this tool links to it rather than pronouncing on validity.
PC-N01 This country has no postcodes
A postcode was supplied for a country that does not have a postcode system at all. Whatever is in the field came from somewhere else — a default, a copied row, or a form that made the field mandatory everywhere.
Fix: Leave the field empty for this country.
Source: Patterns come from the libaddressinput metadata that Chrome and Android use for address validation, not from the postal authorities themselves — those sit behind a paid Universal Postal Union service. Every pattern is checked against that dataset’s own example postcodes before it is carried here, and where a country publishes an official lookup this tool links to it rather than pronouncing on validity.
PC-R01 Postcode missing where the country expects one
This country’s address format requires a postcode and none was given. Delivery may still work, but rate calculation and address validation at the carrier usually will not.
Source: Patterns come from the libaddressinput metadata that Chrome and Android use for address validation, not from the postal authorities themselves — those sit behind a paid Universal Postal Union service. Every pattern is checked against that dataset’s own example postcodes before it is carried here, and where a country publishes an official lookup this tool links to it rather than pronouncing on validity.
PC-C01 Country not recognised
The country code is not one this tool carries, so there is no format to check against. UK is the usual culprit — the United Kingdom is GB.
Fix: Use the ISO 3166-1 alpha-2 code.
Source: Patterns come from the libaddressinput metadata that Chrome and Android use for address validation, not from the postal authorities themselves — those sit behind a paid Universal Postal Union service. Every pattern is checked against that dataset’s own example postcodes before it is carried here, and where a country publishes an official lookup this tool links to it rather than pronouncing on validity.
PC-U01 No pattern carried for this country
The country is real and does use postcodes, but this dataset carries no pattern for it. Nothing is claimed about the value rather than guessing at one.
Source: Patterns come from the libaddressinput metadata that Chrome and Android use for address validation, not from the postal authorities themselves — those sit behind a paid Universal Postal Union service. Every pattern is checked against that dataset’s own example postcodes before it is carried here, and where a country publishes an official lookup this tool links to it rather than pronouncing on validity.
PC-V01 Matches the expected format
The value matches the pattern this country normally uses.
Source: Patterns come from the libaddressinput metadata that Chrome and Android use for address validation, not from the postal authorities themselves — those sit behind a paid Universal Postal Union service. Every pattern is checked against that dataset’s own example postcodes before it is carried here, and where a country publishes an official lookup this tool links to it rather than pronouncing on validity.
Carrying formats for 181 countries and territories, of which 98 publish an official lookup. Format only — never existence.