Date Range (ISO 8601) Regex for PHP

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching date range (iso 8601), 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
// Date Range (ISO 8601)
// ReDoS-checked | RegexVault — Localization > Date Formats

define('DATE_RANGE_ISO_8601_PATTERN', '/^((?:19|20)[0-9]{2}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12][0-9]|3[01]))\/((?:19|20)[0-9]{2}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12][0-9]|3[01]))$/');

function validate_date_range_iso_8601(string $input): bool {
    return (bool) preg_match(DATE_RANGE_ISO_8601_PATTERN, $input);
}

// Example
var_dump(validate_date_range_iso_8601("2024-01-01/2024-12-31")); // bool(true)

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Date Formats category and has been checked for ReDoS risk. 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

Capture group 1: start date, group 2: end date. This pattern does not validate that the start date precedes the end date — enforce that at application level. ISO 8601 also supports duration syntax (P1Y/2024-01-01) not covered here.