ZIP Code

No because i don't ever put a plus sign in front of my zip code.

I suspect you may be asking about telephone country codes rather than postal ZIP Codes. The plus sign in front of a telephone country code indicates that an international telephone number follows, and the person calling that number should substitute the appropriate international dialing prefix for the plus sign.

(The plus sign in an international telephone number means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)

Use the ZIP Code locator provided by the US Postal Service. It is updated weekly, unlike other sites which are updated monthly at best. The direct URL for the ZIP Code Locator is:

http://zip4.usps.com/zip4/welcome.jsp

Some ZIP Codes, such as for small towns or suburbs, can be determined only from the town name. Others, such as for cities such as Los Angeles, will require a specific address to determine the correct ZIP Code. The USPS lookup allows either method.