What is the ultimate postal code and zip regex?

Question

I'm looking for the ultimate postal code and zip code regex. I'm looking for something that will cover most (hopefully all) of the world.

Answer 1

This looks like a good reference although it's not in Regex.

Really, unless you're actually shipping something to your users, I don't think it's worth the effort. And if you are shipping it, there are address cleaning tools/services you can look into to make it way easier on yourself.

Answer 2

Given that there are so many edge cases for each country (eg. London addresses may use a slightly different format to the rest of the UK) I don't think that there is an ultimate regex other than maybe:

([0-9][a-z][A-Z])+

Best of going with a fairly broad pattern (well not quite as broad as the above), or treat each country/region with a specific pattern of its own!

UPDATE: However, it may be possible to dynamically construct a regex based upon lots of smaller, region specific rules - not sure about performance though!

Lots of country specific patterns can be found on the RegExLib site.

Answer 3

There is none.

Postal/zip codes around the world don't follow a common pattern. In some countries they are made up by numbers, in others they can be combinations of numbers an letters, some can contain spaces, others dots, the number of characters can vary from two to at least six...

What you could do (theoretically) is create a seperate regex for every country in the world, not recommendable IMO. But you would still be missing on the validation part: Zip code 12345 may exist, but 12346 not, maybe 12344 doesn't exist either. How do you check for that with a regex?

You can't.

Answer 4

Depending on your application, you might want to implement regex matching for the countries where most of your visitors originate and no validation for the rest (accept anything).

Answer 5

Why are you doing this and why do you care? As Tom Ritter pointed out, it doesn't matter whether you even have a ZIP/postal code at all, much less whether it's valid or not, until and unless you are actually going to be sending something to that address. Even if you expect that you will be sending them something someday, that doesn't mean you need a postal code today.

Answer 6

As noted elsewhere the variation around the world is huge. And even if something that matches the pattern does not mean it exists.

Then, of course, there are many places where postcodes are not used (e.g. much or Ireland).

Answer 7

You have a problem. You write a regex for it.

Now you have two problems.

Answer 8

We use the following:

Canada

([A-Z]{1}[0-9]{1}){3}   //We raise to upper first

America

[0-9]{5}                //-or-
[0-9]{5}-[0-9]{4}       //10 digit zip

Other

Accept as is

Answer 9

Trying to cover the whole world with one regular expression is not completely possible, and certainly not feasible or recommended.

Not to toot my own horn, but I've written some pretty thorough regular expressions which you may find helpful.

• Canadian postal codes
• US ZIP codes
• UK post codes

It is not possible to guarantee accuracy without actually mailing something to an address and having the person let you know when they receive it, but we can narrow things by down by eliminating cases that we know are bad.

Answer 10

The problem is going to be that you probably have no good means of keeping up with the changing postal code requirements of countries on the other side of the globe and which you share no common languages. Unless you have a large enough budget to track this, you are almost certainly better off giving the responsibility of validating addresses to google or yahoo.

Both companies provide address lookup facuilities through a programmable API.