REGEXVAULTv2.0
Localization/Date Formats
Verified Safe

US Date Format (MM/DD/YYYY) Regex for Java

/^(0?[1-9]|1[0-2])/(0?[1-9]|[12][0-9]|3[01])/((?:19|20)[0-9]{2})$/

What this pattern does

This page provides a well-structured, multi-part regular expression for matching us date format (mm/dd/yyyy), ported and verified for Java. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Java project — whether you're validating in a Spring Boot controller, a Jakarta EE service, or a standalone utility class.

Java Implementation

Java
// US Date Format (MM/DD/YYYY)
// ReDoS-safe | RegexVault — Localization > Date Formats

import java.util.regex.Pattern;

public class UsDateFormatMmddyyyyValidator {
    private static final Pattern PATTERN =
        Pattern.compile("^(0?[1-9]|1[0-2])/(0?[1-9]|[12][0-9]|3[01])/((?:19|20)[0-9]{2})$");

    public static boolean validate(String input) {
        return PATTERN.matcher(input).matches();
    }

    // Example
    public static void main(String[] args) {
        System.out.println(validate("01/15/2024")); // true
    }
}

Test Cases

Matches (Valid)
Rejects (Invalid)
01/15/202400/15/2024
1/5/202413/15/2024
12/31/199901/32/2024
03/01/20242024/01/15
15/01/2024
01-15-2024

When to use this pattern

This pattern is drawn from the Localization > Date Formats category and carries a ReDoS-safe certification. That matters for Java developers because critical in Java applications since the JVM regex engine uses backtracking and is susceptible to ReDoS without careful pattern design. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Never accept US date format as input without explicit documentation — the ambiguity causes silent data corruption. Always ask users to confirm the format or use a locale-aware date picker.

Technical Notes

US format is ambiguous outside the US — 01/05/2024 is January 5th to Americans and May 1st to most of the world. Capture groups: 1=month, 2=day, 3=year. Normalize to ISO 8601 for storage.

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