When sending your business mail, it's important to include the ZIP Codes for your business and the recipient on the package or envelope so your item moves efficiently through the postal system. While the USPS might still process mail without the ZIP Code, you risk both delays and potentially lost mail. For your convenience, you can use the USPS ZIP Code locator tool, which you can access through the "Quick Tools" menu option on the USPS website.


The USPS website has a tool you can use to easily find a ZIP Code by address or city. You can also obtain the ZIP Code through online research and communication with the company.

How USPS ZIP Codes Work

The postal service implemented the first form of ZIP Codes in the 1940s to make it easier to sort mail by city and state. While these numbers first had just two digits, they expanded to the standard five-digit ZIP Codes we see today. USPS eventually added four additional digits separated with a hyphen — called a ZIP+4 Code — to provide more specific details about the destination.

The USPS breaks down a ZIP+4 Code as follows:

  • The first three digits will refer to a large area, like a city.

  • The last two digits before the hyphen will point to a specific delivery area or local post office.

  • The first two digits after the hyphen refer to city blocks or a particular sector.

  • The last two digits might refer to a specific part of a street or a sector.

Find ZIP Code by Address

As long as you can locate everything about the address except for the ZIP Code, you can simply perform a USPS ZIP Code search by address. Click the "Find by Address" button on the USPS tool and type the full street address with city and state at a minimum. You can also enter the company name and any suite or floor number. Click "Find" to see the USPS-formatted address with the five-digit ZIP Code and its extra four digits.

If the tool reports an error finding that particular address, try leaving off the company name and search again. You might also use a search engine to verify the street number and name, suite number and neighborhood.

Search by City and State

If you're curious about the ZIP Codes that span a particular city, go to the USPS ZIP Code search tool and select the button to "Find by City & State". After you type the city name, choose the state from the menu and click "Find." You'll then see each ZIP Code that matches that location.

While a small town may list just one ZIP Code, large cities can have a ZIP Code list with dozens of results, and you'll need to navigate through several pages. USPS will also identify any special ZIP Codes reserved for PO Box usage.

USPS ZIP Code Finder Alternatives

While you'll very likely find the ZIP Code you need using these methods, you do have a few alternatives to consider:

  • Do a web search: When you type the business's name into Google, Yahoo or Bing, you'll often see a special local result that shows the address with ZIP Code along with the company's website, reviews, phone number and other details. You can also go to the company's official website and find the contact page that should show the full address. However, such methods may not show the ZIP Code's extra four digits if you need them.
  • Check previous mail and documents: If the company has sent you mail before, you could check letters and envelopes to see the sender's ZIP Code. Documents such as advertisements, invoices and catalogs may also have this information.
  • Contact the company: If the business has little presence on the web, look up the phone number and give them a call to ask for the ZIP Code. You can also ask in person if possible.