ZIP+4 Lookup | ToolTrio
Also called a zip code lookup +4, zip plus 4 lookup, or 9 digit zip code lookup — the 4 extra digits USPS uses to pinpoint your exact delivery point.
A zip+4 lookup by address only works with a complete street address — city, state, and 5-digit ZIP alone aren't enough. USPS needs the house/suite number to assign the last 4 digits.
How to Use the ZIP+4 Lookup
A zip+4 lookup by address only works with a complete street address — city, state, and 5-digit ZIP alone aren't enough. USPS needs the house/suite number to assign the last 4 digits.
9 Digit Zip Code
A 9 digit zip lookup narrows your address down to a specific block, floor, or P.O. Box — far more precise than the base 5-digit zip.
Postage Savings
Zip +4 qualifies bulk mailers for 10–20 cent per piece USPS presort discounts.
DPV Validation
A valid zip+4 code lookup by address confirms USPS has a real, deliverable record for that address.
5-Digit ZIP vs. ZIP+4 vs. Delivery Point Barcode
Choose the tool by matching your starting information to the output you need.
| TOOL / OPTION | STARTS WITH | BEST FOR |
|---|---|---|
| 5-digit ZIP | 90210 | General mail, most online forms, everyday use |
| ZIP+4 (9 digit zip code) | 90210-1234 | Bulk mail discounts, address verification, KYC checks |
| Delivery Point Barcode | 11-digit code | USPS carrier-route presort — the deepest automation discount |
ZIP+4 Format Breakdown — What Each Part Means
How a 9 digit zip code lookup like 90210-1234 is put together
| Part | Digits | What It Identifies |
|---|---|---|
| Base ZIP | Digits 1–5 | General delivery area (city or region) — e.g. 90210 |
| Sector | Digits 6–7 | A group of streets, a building, or a cluster of P.O. Boxes |
| Segment | Digits 8–9 | One side of a block, a floor, or a specific suite/box range |
| Full ZIP+4 | All 9 digits | Format: NNNNN-NNNN, e.g. 90210-1234 |
Who Benefits from This ZIP+4 Lookup?
Beyond simple lookup, our data helps professionals across industries make accurate, location-based decisions.
E-commerce Checkout
A zip+4 code lookup by address at checkout catches bad addresses before a package ships, cutting failed deliveries.
Bulk & Direct Mail
Presorting by zip plus 4 unlocks USPS carrier-route discounts of 10–20¢ per piece.
KYC & Insurance
Banks and insurers use a usps zip 4 lookup to confirm an address is real before approving an application.
CRM Data Cleanup
Running a 9 digit zip code lookup across a contact list flags undeliverable records before a mailing.
Zip Code Plus 4 Lookup — What Is My 9 Digit Zip Code?
Also called a zip code lookup +4, zip plus 4 lookup, or 9 digit zip code lookup — the 4 extra digits USPS uses to pinpoint your exact delivery point.
A zip code lookup +4 — also written zip+4, zip plus 4, or a 9 digit zip code lookup — takes the standard 5-digit ZIP and adds 4 more digits after a hyphen (NNNNN-NNNN). Those extra digits are what USPS uses to route mail down to a specific city block, building floor, or P.O. Box, instead of just a general delivery area.
Most people only need their 5-digit ZIP for everyday use. You need the full zip+4 when a form, a shipping label, or a mailing list specifically asks for the 9 digit zip code — usually for bulk mail discounts or stricter address verification.
There's no way to guess or calculate a zip+4 from a ZIP code alone — the exact 4-digit suffix is tied to your specific street address and is only assigned by USPS. Check your base ZIP below, then use the official USPS zip +4 lookup with your full address to get the exact 9 digits.
Official Data Sources & Resources
We verify our data against official United States government databases to ensure accuracy.
*This website is a private tool and is not affiliated with the USPS or the US Government. "ZIP Code" is a registered trademark of the USPS.
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Frequently Asked Questions
Real questions from users — answered with detail and precision.
What is the plus 4 on a zip code?▼
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