[shiflett]

It's more complicated than that. The last line has to match two out of three (for example, city and ZIP), and then it can try to do some reverse analysis on what you've written for the address line. (Even that's an oversimplification; it's pretty darn impressive.)

The USPS also has the additional challenge of matching what you think is your address with what is actually your address. Very, very few people know their address.

If that's not bad enough, if you've ever had something arrive successfully, you expect the address that was used to work forever.

[kd0amg]

The USPS also has the additional challenge of matching what you think is your address with what is actually your address. Very, very few people know their address.

What parts of their addresses do people typically get wrong? Where can one go to find one's actual address?

[jloughry]

Here's where you can go to find your actual address:

    https://tools.usps.com/go/ZipLookupAction_input

There are, occasionally, errors in the database. I'm trying to get one corrected now. If you find one, go to your local Post Office, find a supervisor, and ask him or her to notify "Address Management".

[sambe]

There is not always one answer. In the UK the Royal Mail, electoral roll, credit reference agencies etc can disagree with each other.

[encoderer]

I didn't mean to short shrift them -- hell I brought it up to praise them.

I've been so impressed before by things like wrong addresses -- hell, one time I saw a letter with no address only my name and zip code. And it's not like I lived in a place where my mail carrier knew me. They've built a hell of a technology there.