Currency Validation Regex (USD)

Validate US Dollar currency format with optional dollar sign, comma separators, and two decimal places using regex pattern.

Pattern Breakdown

^\$?(\d{1,3}(,\d{3})*|(\d+))(\.\d{2})?$

Components

Detailed Breakdown

• \$? - Optional dollar sign (escaped $)
• (\d{1,3}(,\d{3})*|(\d+)) - Amount alternation:
  • \d{1,3}(,\d{3})* - Comma-formatted: 1-3 digits, then groups of 3 digits with commas
  • |(\d+) - OR plain number without commas
• (\.\d{2})? - Optional cents: dot and exactly 2 digits

Examples

Valid:

• $100
• $1,000
• $1,234.56
• 100
• 1,000
• 1234.56
• $0.50
• $1,000,000.00

Invalid:

• $1,23 (incorrect comma placement)
• $1,234.5 (only one decimal place)
• $1,234.567 (three decimal places)
• $$100 (double dollar sign)
• 100.5 (one decimal place)
• 1,00 (incorrect comma format)

Implementation

JavaScript

const currencyRegex = /^\$?(\d{1,3}(,\d{3})*|(\d+))(\.\d{2})?$/;
currencyRegex.test('$1,234.56'); // true
currencyRegex.test('100'); // true
currencyRegex.test('$1,000'); // true
currencyRegex.test('$1,234.5'); // false (one decimal place)
currencyRegex.test('$1,23'); // false (incorrect comma)

Python

import re
currency_regex = r'^\$?(\d{1,3}(,\d{3})*|(\d+))(\.\d{2})?$'
bool(re.match(currency_regex, '$1,234.56'))  # True
bool(re.match(currency_regex, '100'))  # True
bool(re.match(currency_regex, '$1,234.5'))  # False (one decimal place)

Go

currencyRegex := regexp.MustCompile(`^\$?(\d{1,3}(,\d{3})*|(\d+))(\.\d{2})?$`)
currencyRegex.MatchString("$1,234.56") // true
currencyRegex.MatchString("100") // true
currencyRegex.MatchString("$1,234.5") // false (one decimal place)

Limitations

1. No negative amounts: Doesn't support negative currency
2. Fixed decimal places: Requires exactly 2 decimal places if decimal is present
3. US format only: Uses comma for thousands, dot for decimal
4. No currency code: Doesn't validate currency codes (USD, EUR, etc.)
5. Format only: Validates format, not actual monetary value

When to Use

• USD currency input validation
• Price input forms
• Financial application inputs
• When you need US currency format
• E-commerce price validation

For production, consider:

• Supporting negative amounts if needed: ^-?\$?(\d{1,3}(,\d{3})*|(\d+))(\.\d{2})?$
• Making cents optional: (\.\d{1,2})?
• Supporting different locale formats
• Validating against maximum amounts
• Using currency formatting libraries