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ZIP Code Validator

DataDeveloperText

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INPUT

Auto Process

OUTPUT

Client Side

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Guide

ZIP Code Validator

Quickly validate US ZIP codes to check whether they follow the correct 5-digit or ZIP+4 format. Paste one or multiple ZIP codes and get instant validation results with clear valid/invalid badges.

How to Use

Enter one or more US ZIP codes in the input field, one per line. The tool automatically validates each ZIP code as you type, showing whether it matches the standard 5-digit format (e.g., 90210) or the extended ZIP+4 format (e.g., 90210-1234). A summary displays the total count of valid and invalid entries.

Features

Dual Format Support – Validates both 5-digit ZIP codes and ZIP+4 extended codes
Bulk Validation – Check multiple ZIP codes at once, one per line
Real-Time Results – Validation happens instantly as you type
Clear Visual Feedback – Color-coded valid/invalid badges for each entry
Summary Statistics – See total valid and invalid counts at a glance

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 FAQ

What is the difference between a 5-digit ZIP code and ZIP+4?

A 5-digit ZIP code identifies a general delivery area, while ZIP+4 adds four extra digits after a hyphen to pinpoint a specific block, building, or PO box within that area. The extended format helps postal services sort mail more efficiently.
Are all 5-digit number combinations valid ZIP codes?

No. While any 5-digit string matches the correct format, not all combinations are assigned to actual geographic areas. The USPS maintains the official list of active ZIP codes, and many 5-digit combinations are unassigned or reserved.
Why were ZIP codes introduced in the United States?

ZIP codes were introduced in 1963 by the United States Postal Service to improve mail sorting and delivery efficiency. The acronym stands for Zone Improvement Plan, and the system replaced earlier postal zone numbers used in large cities.