Financial Year (FY2024 / FY2024-25) Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching financial year (fy2024 / fy2024-25), ported and verified for JavaScript. Financial data validation has zero tolerance for false negatives — a missed invalid entry can corrupt downstream calculations. The snippet below is ready to drop into your JavaScript project — whether you're validating in an Express middleware, a Next.js API route, or a client-side form.

Javascript Implementation

// Financial Year (FY2024 / FY2024-25)
// ReDoS-safe | RegexVault — Finance > Financial Formats

const financialYearFy2024Fy202425Regex = /^FY[0-9]{4}(?:[\/-][0-9]{2})?$/i;

function validateFinancialYearFy2024Fy202425(input: string): boolean {
  return financialYearFy2024Fy202425Regex.test(input);
}

// Example
console.log(validateFinancialYearFy2024Fy202425("FY2024")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Financial Formats category and carries a ReDoS-safe certification. That matters for JavaScript developers because especially critical in long-running Node.js event loops where a ReDoS vulnerability can block the entire process. 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: fiscal year start, group 2: end year (short or long form). Straddling years (FY2024-25 = April 2024 to March 2025) are common in UK, India, and Australia.