To verify an address, enter it in the free USPS ZIP Code Lookup at tools.usps.com and search by address: if USPS returns a standardized version with a ZIP+4 code, the address exists in the postal database and you should copy that version onto your label. If USPS can’t match it, check the unit number, street spelling and ZIP code, then confirm with the recipient before you ship.
Verifying first matters because a bad address costs more after the label is printed. UPS charges the shipper an Address Correction fee when it has to fix an incorrect or incomplete address, and USPS typically returns an undeliverable package to the sender. This guide covers the steps, the tools, and what to do when an address won’t verify.
How Do You Verify an Address Step by Step?
- Get the full address from the recipient. You need the name, street number and name, apartment or suite number, city, state and ZIP code. Our checklist of the address information required for delivery lists every element.
- Look it up with USPS. On the USPS ZIP Code Lookup, choose the search by address and enter the street, city and state.
- Read the result. A match returns the address in USPS standard format (capital letters, standard abbreviations such as ST and APT) with a ZIP+4 code. No match, or a prompt for more information, means something is missing or wrong.
- Check the unit number. For apartments and offices, make sure the result includes the right unit. A building can verify while the unit is missing, and missing secondary information is one of the most common reasons a package can’t be delivered.
- Use the standardized version on the label. Copy the address exactly as USPS returns it, including the ZIP+4.
- Confirm anything unusual with the recipient. New construction, rural routes and PO Boxes are worth a quick message before you ship.
Once the address is right, the way you write it on the box matters too; see our steps for how to address a box for shipping.
What Does Address Verification Actually Check?
Address verification confirms that an address exists and can receive mail, not just that it looks correct. USPS’s PostalPro site describes the systems behind it, which commercial address software must pass to earn USPS CASS certification:
| Term | What it checks |
|---|---|
| CASS (Coding Accuracy Support System) | Certifies that address software assigns ZIP Codes, ZIP+4, delivery point codes and carrier routes accurately |
| DPV (Delivery Point Validation) | Confirms the specific address is a valid delivery point, not just a valid street range |
| RDI (Residential Delivery Indicator) | Flags whether the address is residential or business |
| SuiteLink | Adds known suite numbers to business addresses |
| LACSLink | Converts addresses changed by local renaming, such as a rural route converted for 911 service, to the new address |
Address validation and address verification are often used interchangeably, but strictly, validation checks the format (required fields, a valid state, a five-digit ZIP), while verification checks the address against the postal database. Our guide to USPS address verification with CASS, DPV and the AMS database goes deeper into how USPS’s data works.
What Tools Can You Use to Verify an Address?
- USPS ZIP Code Lookup (free). The quickest way to check one U.S. address, available on usps.com.
- Label-creation tools. Most carrier and shipping tools check the address when you create a label and suggest a corrected version. Read the suggestion before you accept it, rather than clicking through.
- USPS APIs. For developers, USPS retired its older Web Tools APIs on January 25, 2026; the replacements, including an Addresses API, are in the USPS API Catalog at developers.usps.com.
- UPS Address Validation. UPS offers Address Validation through its developer APIs and shipping tools, and can classify addresses as residential or commercial.
- CASS-certified software. Businesses cleaning a large customer list use CASS-certified address software, which applies the USPS checks above in bulk.
If you also ship with FedEx, our guides to FedEx address verification and FedEx address lookup cover its tools.
When Should You Verify an Address?
Verify at the points where errors get in, not just once.
- At checkout. If you sell online, address suggestions at checkout catch typos before the order exists.
- Before printing the label. Orders from marketplaces such as Etsy come with the address the buyer typed, so check unusual ones before you buy postage.
- For repeat shipments. Re-check stored addresses for subscriptions and regular customers from time to time, since people move.
- After a change-of-address notice. Update your records as soon as a customer or carrier tells you an address has changed.
Why Does Residential vs. Commercial Matter?
UPS adds a residential surcharge for deliveries to homes, so a business address entered as residential, or the reverse, can change the price after the fact. Verification tools that use USPS’s RDI data or UPS’s own classification tell you which applies before you buy the label. Our explainer on what counts as a commercial address covers the rules.
USPS doesn’t charge a residential surcharge, which is one reason it’s often the cheaper carrier for light packages going to homes. You can compare live UPS and USPS rates for the verified address in the ParcelPath rate calculator.
What Happens When an Address Won’t Verify?
Don’t ship until you’ve resolved it. Work through the usual causes in this order:
- Typos and abbreviations. A misspelled street, “St” where it should be “Dr”, or swapped digits in the house number.
- Missing unit number. The building verifies but the apartment or suite doesn’t.
- Wrong ZIP code. A ZIP that doesn’t match the city and state.
- New construction. Brand-new addresses can take time to appear in the postal database.
- Rural or non-standard addresses. Some properties use rural route or box numbers instead of street numbers.
If none of those fixes it, ask the recipient to confirm the address, or ship to a Post Office, UPS Store or UPS Access Point for pickup. Note that UPS says an address it validated can still be incorrect or incomplete for delivery, so a verified result isn’t a guarantee.
What If You Already Shipped to a Wrong Address?
Act quickly, because options shrink once the package is out for delivery. With USPS, Package Intercept can redirect an eligible package for a fee, and our guide to USPS address correction services covers the alternatives. With UPS, the carrier may correct the address itself and bill an Address Correction charge, or you can request a delivery change through UPS. For FedEx shipments, see how to fix a FedEx delivery exception for an incorrect address.
ParcelPath is free to use for UPS and USPS labels, with no subscription or per-label fee and up to 85% off UPS and up to 89% off USPS retail rates, so the money you’d lose to a correction fee stays in your shipping budget. Keeping a packing slip in the box with the order details also helps a carrier or recipient sort out a misdelivery.
Frequently Asked Questions
How can I verify an address for free?
Use the USPS ZIP Code Lookup on usps.com and search by address. If USPS returns the address in standard format with a ZIP+4 code, it’s a recognized delivery address. If it can’t find a match, check the unit number, street spelling and ZIP, then confirm with the recipient. The tool covers U.S. addresses only.
What is the difference between address validation and address verification?
Validation checks that an address is formatted correctly: required fields filled in, a real state abbreviation and a properly formed ZIP code. Verification goes further and confirms the address exists in the postal database as a deliverable point, using checks such as USPS Delivery Point Validation (DPV). Verification is what prevents correction fees and returns.
Does UPS charge for a wrong address?
Yes. UPS’s Rate and Service Guide says that when a shipment has an incorrect or incomplete address, UPS will try to find the correct one and charge the shipper an Address Correction fee. UPS also notes that an address it validated can still need correcting, so confirm unusual addresses with the recipient before shipping.
Can you verify an international address with USPS?
No. The USPS ZIP Code Lookup only verifies U.S. addresses. For an international shipment, follow the destination country’s address format, include the postal code, and confirm the address with the recipient. Some carrier label tools also check international addresses when you create the label.
Sources
- USPS: ZIP Code Lookup by address
- USPS PostalPro: CASS certification (DPV, RDI, SuiteLink, LACSLink)
- USPS: Web Tools APIs retirement (January 25, 2026) and the USPS API Catalog
- UPS Rate and Service Guide, Daily Rates: Address Correction and Address Validation
Part of our Packing Slip guide. Related: Dymo vs Zebra, Do I Need a Special Printer to Print Postage at Home, Abbreviation for Shipping.
