US Date Format (MM/DD/YYYY) Regex for JavaScript

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 JavaScript. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. 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

// US Date Format (MM/DD/YYYY)
// ReDoS-safe | RegexVault — Localization > Date Formats

const usDateFormatMmddyyyyRegex = /^(0?[1-9]|1[0-2])\/(0?[1-9]|[12][0-9]|3[01])\/((?:19|20)[0-9]{2})$/;

function validateUsDateFormatMmddyyyy(input: string): boolean {
  return usDateFormatMmddyyyyRegex.test(input);
}

// Example
console.log(validateUsDateFormatMmddyyyy("01/15/2024")); // 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 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

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.