Korean Date Format (YYYY년 MM월 DD일) Regex for PHP

What this pattern does

This page provides a well-structured, multi-part regular expression for matching korean date format (yyyy년 mm월 dd일), ported and verified for PHP. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your PHP project — whether you're validating in a Laravel validator, a WordPress plugin, or a standalone PHP script.

Php Implementation

<?php
// Korean Date Format (YYYY년 MM월 DD일)
// ReDoS-safe | RegexVault — Localization > Date Formats

define('KOREAN_DATE_FORMAT_YYYY_MM_DD_PATTERN', '/^((?:19|20)[0-9]{2})년\s?(0?[1-9]|1[0-2])월\s?(0?[1-9]|[12][0-9]|3[01])일$/');

function validate_korean_date_format_yyyy_mm_dd(string $input): bool {
    return (bool) preg_match(KOREAN_DATE_FORMAT_YYYY_MM_DD_PATTERN, $input);
}

// Example
var_dump(validate_korean_date_format_yyyy_mm_dd("2024년 1월 15일")); // bool(true)

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Date Formats category and carries a ReDoS-safe certification. That matters for PHP developers because especially relevant in PHP where PCRE backtracking limits can trigger silent failures on malicious input. 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

Technical Notes

Korean uses 년 (year), 월 (month), 일 (day). Spaces between the components are optional. The optional \s? handles both spaced and unspaced forms. Korea uses the Gregorian calendar exclusively for civil purposes.