Fiscal Quarter (QN YYYY or YYYY QN) Regex for PHP

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching fiscal quarter (qn yyyy or yyyy qn), 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
// Fiscal Quarter (QN YYYY or YYYY QN)
// ReDoS-safe | RegexVault — Localization > Date Formats

define('FISCAL_QUARTER_QN_YYYY_OR_YYYY_QN_PATTERN', '/^(?:(Q[1-4])\s+((?:19|20)[0-9]{2})|((?:19|20)[0-9]{2})\s+(Q[1-4]))$/');

function validate_fiscal_quarter_qn_yyyy_or_yyyy_qn(string $input): bool {
    return (bool) preg_match(FISCAL_QUARTER_QN_YYYY_OR_YYYY_QN_PATTERN, $input);
}

// Example
var_dump(validate_fiscal_quarter_qn_yyyy_or_yyyy_qn("Q1 2024")); // 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

Capture groups: 1=quarter (QN format), 2=year (QN format), 3=year (YQ format), 4=quarter (YQ format). Fiscal quarters may not align with calendar quarters — Q1 may start in January, April, July, or October depending on the company's fiscal year.