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})$/What this pattern does
This page provides a well-structured, multi-part regular expression for matching us date format (mm/dd/yyyy), ported and verified for Java. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Java project — whether you're validating in a Spring Boot controller, a Jakarta EE service, or a standalone utility class.
Java Implementation
// US Date Format (MM/DD/YYYY)
// ReDoS-safe | RegexVault — Localization > Date Formats
import java.util.regex.Pattern;
public class UsDateFormatMmddyyyyValidator {
private static final Pattern PATTERN =
Pattern.compile("^(0?[1-9]|1[0-2])/(0?[1-9]|[12][0-9]|3[01])/((?:19|20)[0-9]{2})$");
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) |
|---|---|
01/15/2024 | 00/15/2024 |
1/5/2024 | 13/15/2024 |
12/31/1999 | 01/32/2024 |
03/01/2024 | 2024/01/15 |
| — | 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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