What’s the Difference Between a ZIP Code and ZIP+4?

The main difference between a ZIP code and a ZIP+4 code is the level of postal detail they provide.

A standard U.S. ZIP code has five digits, while a ZIP+4 code contains the same five digits followed by a hyphen and four additional digits.

For example:

ZIP Code: 12345
ZIP+4 Code: 12345-6789

A standard ZIP code represents a postal delivery area. A ZIP+4 provides more specific postal information within that area.

What Is a ZIP Code?

A ZIP code is a postal code used by the United States Postal Service (USPS) to help sort and route mail.

For example:

12345

One five-digit ZIP code can cover many:

Streets
Houses
Apartments
Offices
Businesses
Buildings

Because a ZIP code represents a postal area, the five-digit code by itself does not identify one unique street address.

What Is a ZIP+4 Code?

ZIP+4 is the extended form of the standard ZIP code.

It looks like this:

12345-6789

It consists of:

12345 – Standard five-digit ZIP code
6789 – Four additional digits

The extra four digits provide more specific postal information within the five-digit ZIP code area.

ZIP Code vs. ZIP+4

Feature	ZIP Code	ZIP+4
Format	12345	12345-6789
Number of digits	5	9
Purpose	Identifies a postal delivery area	Provides more specific postal information
Level of detail	General	More specific
Example	10001	10001-2345

Note: The codes shown above are examples of the formats only. They should not be treated as verified ZIP or ZIP+4 codes for a particular address.

Why Does ZIP+4 Have Four Extra Digits?

The four additional digits provide more specific postal routing information within the basic five-digit ZIP code area.

This can help USPS identify a more specific delivery segment.

Therefore, ZIP+4 provides more detailed postal information than the standard five-digit ZIP code alone.

Does Every Address Have the Same ZIP+4?

Do not assume that all addresses within the same five-digit ZIP code use the same ZIP+4.

A single five-digit ZIP code can represent many:

Delivery points
Streets
Buildings
Apartments
Businesses
Other delivery areas

If you need the ZIP+4 for a particular mailing address, perform an address-based lookup instead of copying an extended ZIP code from a nearby address.

How to Find the ZIP+4 for an Address

Use the official USPS ZIP Code Lookup.

Follow these simple steps:

Open the official USPS ZIP Code Lookup.
Select By Address.
Enter the building or house number.
Enter the street name.
Add the apartment, suite, or unit information when applicable.
Enter the city.
Select the state.
Click Find.
Compare the returned address with the address you entered.
Use the ZIP+4 shown for the matching address.

Never guess the final four digits.

Can I Use Only the Five-Digit ZIP Code?

The five-digit ZIP code provides basic information about the postal delivery area.

If you need the ZIP+4 for a particular address, use an official address-based lookup to find the extended code.

For important mail, make sure all parts of the mailing address are correct, including:

Recipient name or information
House or building number
Street name
Apartment or suite number, when applicable
City
State
ZIP code or ZIP+4

Checking the complete address is more reliable than relying only on a ZIP code.

Frequently Asked Questions

Is ZIP+4 the Same as a 9-Digit ZIP Code?

Yes. A ZIP+4 contains nine numerical digits in total.

It is normally written as:

12345-6789

This includes the five-digit ZIP code, a hyphen, and four additional digits.

Is ZIP+4 More Specific Than a ZIP Code?

Yes. A ZIP+4 provides more specific postal information within a standard five-digit ZIP code area.

Can I Find My ZIP+4 From My ZIP Code Alone?

Do not try to calculate or guess the additional four digits from your five-digit ZIP code.

Instead, enter the complete mailing address into an official USPS address-based lookup and check the ZIP+4 returned for the matching address.

Where Can I Find My ZIP+4?

Use the official USPS ZIP Code Lookup.

Enter your complete mailing address, including:

Street address
Apartment or suite number, when applicable
City
State

Then check the ZIP+4 shown for the matching address.

Key Points to Remember

A standard ZIP code contains five digits.
A ZIP+4 contains nine numerical digits in total.
ZIP+4 is normally written as 12345-6789.
A ZIP code identifies a postal delivery area.
ZIP+4 provides more specific postal information.
Do not assume nearby addresses have the same ZIP+4.
Never guess the final four digits.
Use an address-based USPS lookup when you need the ZIP+4 for a specific address.

Final Answer

A ZIP code is a five-digit code that identifies a postal delivery area, while a ZIP+4 contains the five-digit ZIP code plus four additional digits that provide more specific postal information.

For example:

ZIP Code: 12345
ZIP+4: 12345-6789

If you need the ZIP+4 for a particular address, enter the complete address into the official USPS ZIP Code Lookup rather than trying to guess the additional four digits.