Learn the history and meaning of usps postal codes, why it's called a ZIP code, whether a postal code is a ZIP code, and what ZIP code numbers stand for.

Your billing zip code, or credit card postal code, is the five-digit number on the bottom right, which in this sample is 90210. This would be the zip code associated with your billing address.

Press "Find" and USPS will give you the ZIP+4 code. How many stamps to use and mailing costs TODAY / TODAY Placing the stamp on a envelope is easy, it simply goes in the upper righthand corner.