Add ZIP+4 to a Spreadsheet of Addresses
Upload your addresses, get back ZIP+4, carrier routes, and a stack of other USPS data points. No code, no installs, no credit card.
What is ZIP+4, and why do you need it?
A standard ZIP code is five digits. ZIP+4 adds four more digits to the end, separated by a hyphen, and those four digits are doing a surprising amount of work.
The first two digits narrow the address down to a delivery sector, usually a few blocks or a single large building.
The last two digits narrow it further to a delivery segment, a specific floor, a department, or even one high-volume mailbox.
So 20006 becomes something like 20006-1010, and the USPS knows exactly where to send your mail before it ever leaves the local sorting facility.
ZIP+4 was introduced in 1983 (the same year the original Star Wars trilogy wrapped, for context), and while it's technically optional, using it speeds up delivery, reduces address errors, and unlocks bulk mail discounts.
If you're doing direct mail, address validation, or just want to make sure your data is as clean as possible, adding ZIP+4 is one of the most effective things you can do.
Adding ZIP+4(ZIP9) and carrier route information to a spreadsheet of addresses or coordinates in three steps
1. Organize the addresses or coordinates you want to add ZIP+4 (ZIP9) and carrier route IDs to in a spreadsheet with headers
Make sure you have a header row, and that the addresses are formatted consistently — either with each component in its own column, or all in one column. Either works for Geocodio.
You don't need complete addresses, by the way. Street + ZIP, or street + city + state, is usually enough for us to find a match. Geocodio also does minor spelling correction along the way (no judgment).
Multi-Column Format
| Street | City | State | ZIP |
|---|---|---|---|
| 1600 Pensyvlania Avenue NW | Washington | DC | 20006 |
| 1000 Bank Steet | 23218 | ||
| 75 Rev Dr Martin Luther King Jr Bulvard | St Paul | MN |
Single-Column Format
| Address |
|---|
| 1600 Pennsylvania Avenue NW, Washington DC 20006 |
| 1000 Bank St, 23218 |
| 75 Rev Dr Martin Luther King Jr Boulevard, St Paul MN |
You can also upload coordinates and we'll work backward to the ZIP+4 from there.
2. Upload your file and select the ZIP+4 append
Once your spreadsheet is ready, upload it to Geocodio. You'll confirm your column headers, get a preview of where your addresses are landing on the map, and then in Step 3 you'll see the option to check the ZIP+4 append box.
A few things worth knowing: ZIP+4 appends count as one additional lookup per row, and you're only charged if we successfully find a match. The banner at the bottom of the page shows you a cost estimate, and you can also run the numbers in our pricing calculator before you upload.
3. Download your completed spreadsheet with ZIP+4 (ZIP9) added the addresses
Press Submit, then walk away. Your file processes in the background, and we'll email you when it's ready. You'll get your original data back, plus new columns for ZIP+4, ZIP9, carrier route, and the rest of the USPS append fields (full list below). See the detailed ZIP+4 Guide.
Need to do this programmatically?
If you're integrating ZIP+4 into an application, CRM, or backend system, you'll want the Geocodio API instead. Add ZIP+4 via API →
What you get back with every ZIP+4 lookup
ZIP+4
The 4-digit extension that pinpoints the delivery sector and segment.
ZIP9
The full 9-digit ZIP code as a single string. Handy for systems that store ZIP+4 without the hyphen.
Carrier Route
The specific route a mail carrier walks or drives to reach the address. Direct mail folks live for this field.
Residential Delivery Indicator (RDI)
Determines whether an address is Commercial or Residential.
Record Type
Tells you what kind of address this is: street, PO Box, rural route, highrise, firm, or general delivery.
Building or Firm Name
If the USPS recognizes a business or building at the address, you'll get the name here.
Government Building
A flag that identifies federal, state, or local government addresses.
Valid Delivery Area
Confirms the address is in a valid USPS delivery area. (Yes, mail can actually arrive here.)
City Delivery Indicator
Tells you whether the address is inside a city delivery area, which affects how it gets routed.
Facility Code
The USPS facility code, useful if you're tracking sortation or working with bulk mailers.
Exact Match
Whether the address matches the USPS's authoritative database exactly. Great for confidence scoring.
ZIP+4
The 4-digit extension that pinpoints the delivery sector and segment.
ZIP9
The full 9-digit ZIP code as a single string. Handy for systems that store ZIP+4 without the hyphen.
Carrier Route
The specific route a mail carrier walks or drives to reach the address. Direct mail folks live for this field.
Residential Delivery Indicator (RDI)
Determines whether an address is Commercial or Residential.
Record Type
Tells you what kind of address this is: street, PO Box, rural route, highrise, firm, or general delivery.
Building or Firm Name
If the USPS recognizes a business or building at the address, you'll get the name here.
Government Building
A flag that identifies federal, state, or local government addresses.
Valid Delivery Area
Confirms the address is in a valid USPS delivery area. (Yes, mail can actually arrive here.)
City Delivery Indicator
Tells you whether the address is inside a city delivery area, which affects how it gets routed.
Facility Code
The USPS facility code, useful if you're tracking sortation or working with bulk mailers.
Exact Match
Whether the address matches the USPS's authoritative database exactly. Great for confidence scoring.
What you get back with every ZIP+4 lookup
Related Resources
Estimate Cost
See how much it will cost and how long it will take to add ZIP+4 (including carrier route IDs) to your address data.
USPS ZIP+4 (Full ZIP9) Guide
Geocodio can return USPS ZIP+4 codes along with deliverability indicators for addresses and latitude/longitude coordinates, including PO Boxes.
ZIP+4 API
Add ZIP+4, carrier route IDs, and more to addresses or coordinates programmatically.
Complete guide to ZIP codes
Learn what ZIP codes are, how to find your ZIP code, and use Geocodio's lookup tools for accurate address data.
Unlimited Geocoding
Get a private instance of Geocodio and process up to 5M lookups per day for a flat rate. Includes all data appends, including ZIP+4.
Address Parsing and Standardization
Messy addresses? Geocodio can parse, standardize, and complete your addresses.
By the time you finish reading this page, the Geocodio API will have processed 5.3 million lookups.
Your data could be next...