Body Mass Index (BMI) Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching body mass index (bmi), ported and verified for JavaScript. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. 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

// Body Mass Index (BMI)
// ReDoS-safe | RegexVault — Identity & PII > Biometric & Physical

const bodyMassIndexBmiRegex = /^(?:(?:[1-6][0-9](?:\.[0-9]{1,2})?)|(?:70(?:\.0{1,2})?))$/;

function validateBodyMassIndexBmi(input: string): boolean {
  return bodyMassIndexBmiRegex.test(input);
}

// Example
console.log(validateBodyMassIndexBmi("22.5")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Biometric & Physical 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

Normal BMI range is 18.5-24.9. BMI is a derived health metric — stored in medical records, used in insurance underwriting. As a health data attribute, it falls under GDPR Article 9 sensitive data category when processed for medical purposes.