Date Regex Python Validator

What Is a Date Regex?

A date regex helps you match string values that represent valid dates. Common formats include:

• YYYY-MM-DD → 2024-12-31

• MM/DD/YYYY → 12/31/2024

• DD-MM-YYYY → 31-12-2024

Regex ensures the structure is correct, but not the logical validity (e.g. 31st Feb is still “valid” structurally).

Regex Patterns for Common Date Formats

1. ISO Format (YYYY-MM-DD)
   
   

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

   
   

2. US Format (MM/DD/YYYY)
   
   

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

   
   

3. European Format (DD-MM-YYYY)

   
   

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

   
   

   
   

Python Code Example

import re

def is_valid_date(date_str):
    pattern = re.compile(
        r'^\d{4}-(0[1-9]|1[0-2])-(0[1-9]|[12][0-9]|3[01])$'
    )
    return bool(pattern.fullmatch(date_str))

# Test cases
dates = ["2025-06-12", "2025-02-29", "1999-13-01", "2025-06-31"]
for date in dates:
    print(f"{date} -> {is_valid_date(date)}")

Use Cases

• Form Validation: Validate birthdates, event dates, or booking inputs

• APIs: Enforce valid date strings in payloads

• Databases: Pre-validate date strings before insertion

• Combine with: Email Regex Python Validator, UUID Regex Python Validator, or Phone Number Regex Python Validator

Pro Tips

• Use datetime.strptime alongside regex for real date validation

• Regex won’t catch logical errors like “2025-02-30”

• Use non-capturing groups if you’re optimizing for performance

• Always test edge cases: leap years, end of month, etc.

• Combine with Numbers Regex Python Validator to validate numeric fields in reports