Numbers Regex Javascript Validator

What is Numbers Regex?

In JavaScript, regex (regular expressions) are often used to validate and match numeric inputs such as whole numbers, decimals, and formatted values like currency. This is especially useful in forms, financial calculations, and input validation where the structure of numeric data matters.

JavaScript regex provides concise patterns to distinguish valid numbers and reject anything unexpected, like letters or malformed punctuation.

Regex Patterns for Number Validation

1. Integer Validation

   
   

   Validates whole numbers with no symbols or decimal points.

   
   

   const regex = /^\d+$/;

   
   

   Matches: "123", "2024"

   Doesn’t match: "12.3", "-100"

   
   

2. Decimal Number Validation

   
   

   Validates numbers with optional decimals.

   
   

   const regex = /^\d+\.\d+$/;

   
   

   Matches: "3.14", "99.999"

   Doesn’t match: "100", "abc"

   
   

3. Signed Number Validation

   
   

   Allows optional negative or positive sign.

   
   

   const regex = /^[+-]?\d+(\.\d+)?$/;

   
   

   Matches: "-45", "+99.99", "0"

   Doesn’t match: "--12", "100+"

   
   

4. Formatted Numbers with Commas

   
   

   Matches numbers like 1,000 or 12,345,678.

   
   

   const regex = /^\d{1,3}(,\d{3})*$/;

   
   

   Matches: "1,000", "100,000"

   Doesn’t match: "1000", "1,,000"

How to Validate Numbers in JavaScript

Use the built-in RegExp class or regex literals with methods like .test() or .match():

const number = "12345";
const pattern = /^\d+$/;

console.log(pattern.test(number)); // true

You can test your custom regex using our interactive JavaScript Regex Tester.

Pro Tips

• Use the Numbers Regex Go Validator or Numbers Regex Java Validator for server-side verification of numeric inputs.

• Use the Base64 Decoder if your numeric data is encoded before validation.

• Combine with the Token Generator if you’re building numeric-based authentication systems like OTPs.

• Avoid accepting parseFloat() as validation—it’s not strict and may allow invalid strings like "123abc" to partially pass.

• Always sanitize numeric input alongside regex validation to prevent injection risks or malformed formatting.

Metacharacters Used

• ^ : Start of string

• $ : End of string

• \d : Any digit [0-9]

• + : One or more of the previous

• * : Zero or more of the previous

• ? : Optional (zero or one)

• \. : Escaped dot to match decimal

• [,] : Comma literal

• () : Grouping

• [] : Character class

Examples

Example 1: Validating an Integer

const input = "250";
const pattern = /^\d+$/;

console.log(pattern.test(input)); // true

Try building your own patterns using the JavaScript Regex Tester.

Example 2: Validating a Decimal number

const input = "3.1415";
const pattern = /^\d+\.\d+$/;

console.log(pattern.test(input)); // true

You can further combine this with the Token Generator to auto-generate secure numbers.

Example 3: Detecting Signed and Unsigned Numbers

const input = "-0.99";
const pattern = /^[+-]?\d+(\.\d+)?$/;

console.log(pattern.test(input)); // true

Use this in combination with the JavaScript Regex Tester for rapid debugging.

Use Cases

• Form Validation: Use regex to ensure users enter valid numbers in fields like age, quantity, and budget.

• Financial Apps: Validate decimal precision in transactions and prices.

• Data Cleaning: Filter out bad inputs before importing into analytics tools.

• Auth Systems: Use regex to process numeric OTPs and login tokens generated via the Token Generator.

Combine With These Tools

• JavaScript Regex Tester: Instantly validate number patterns in JavaScript.

• Token Generator: Useful for generating secure numeric strings or OTPs.

• Base64 Decoder: Decode numeric data before applying regex.

• Email Regex JavaScript Validator: Validate numeric data alongside email inputs for complete form handling.

• IP Address Regex JavaScript Validator: Useful if numeric IP values are also being validated.