Date Validation Regex: DD/MM/YYYY Format

Validate dates in European format (DD/MM/YYYY) with proper month and day range validation using regex.

Pattern Breakdown

^(0[1-9]|[12]\d|3[01])/(0[1-9]|1[0-2])/\d{4}$

Components

Detailed Breakdown

• (0[1-9]|[12]\d|3[01]) - Day alternation:
  • 0[1-9] - Days 01-09
  • [12]\d - Days 10-29
  • 3[01] - Days 30-31
• (0[1-9]|1[0-2]) - Month alternation:
  • 0[1-9] - Months 01-09
  • 1[0-2] - Months 10-12
• \d{4} - Year: exactly 4 digits

Examples

Valid:

• 15/03/2024
• 01/01/2024
• 31/12/2024
• 29/02/2024 (format valid, but may not be valid date)
• 01/01/0000 (format valid)

Invalid:

• 15/3/2024 (month not zero-padded)
• 5/03/2024 (day not zero-padded)
• 32/03/2024 (invalid day)
• 15/13/2024 (invalid month)
• 15-03-2024 (wrong separator)
• 2024/03/15 (wrong order)

Implementation

JavaScript

const dateRegex = /^(0[1-9]|[12]\d|3[01])\/(0[1-9]|1[0-2])\/\d{4}$/;
dateRegex.test('15/03/2024'); // true
dateRegex.test('31/12/2024'); // true
dateRegex.test('32/03/2024'); // false (invalid day)
dateRegex.test('15/13/2024'); // false (invalid month)

Python

import re
date_regex = r'^(0[1-9]|[12]\d|3[01])/(0[1-9]|1[0-2])/\d{4}$'
bool(re.match(date_regex, '15/03/2024'))  # True
bool(re.match(date_regex, '31/12/2024'))  # True
bool(re.match(date_regex, '32/03/2024'))  # False (invalid day)

Go

dateRegex := regexp.MustCompile(`^(0[1-9]|[12]\d|3[01])/(0[1-9]|1[0-2])/\d{4}$`)
dateRegex.MatchString("15/03/2024") // true
dateRegex.MatchString("31/12/2024") // true
dateRegex.MatchString("32/03/2024") // false (invalid day)

Limitations

1. No leap year validation: Accepts 29/02/2023 (format valid, date invalid)
2. No month-specific day validation: Accepts 31/04/2024 (April has 30 days)
3. No year range validation: Accepts years like 0000 or 9999
4. Format only: Validates format, not actual date validity
5. Ambiguity with MM/DD/YYYY: Can be confused with US format

When to Use

• European date format validation
• UK, Australia, and most international formats
• When day comes before month
• Forms targeting European users
• Date input in DD/MM/YYYY format

For production, consider:

• Additional validation for actual date validity
• Using date parsing libraries to verify dates
• Validating year ranges
• Clearly labeling format to avoid confusion with MM/DD/YYYY
• Combining with date object validation