USA DLN Validator
Validate USA Driver's License Numbers. Excellent for software QA testing.
How phonetic DLN validation works
The validator cleans input hyphens/spaces and validates total length (13 characters for Florida or 15 characters for New York). It checks if it starts with a letter followed by digits.
It decodes calendar coordinates from the DDD field, determining the birth month, day, and gender mapping to ensure the identity is logically valid.
Anatomy & Structure of US DLN (Florida: 13 Chars / New York: 15 Chars)
Soundex-based state driver licence formats encode demographic and phonetic data:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 | Surname Initial | 1 letter | First letter of driver's last name | S |
| 2 to 4 | Surname Soundex | 3 digits | Phonetic Soundex code of surname consonants | 530 |
| 5 to 7 | First Name Soundex | 3 digits | Phonetic Soundex code of first name consonants | 250 |
| 8 & 9 | Birth Year | 2 digits | Last two digits of birth year (YY) | 85 |
| 10 to 12 | DDD Code (Date/Gender) | 3 digits | (Month - 1) * 40 + Day (+500 added for female drivers) | 585 |
| 13 onwards | Control / Tie-breaker | 1 to 3 chars | Digit "0" in Florida or two tie-breaker digits in New York | 0 |
Soundex Phonetic Algorithm & DDD Date Decoding
State DMVs encode gender and dates using DDD block arithmetic:
DDD = (Month - 1) * 40 + Day + (Female ? 500 : 0)
- 1. Verify first character is a letter (A-Z) and subsequent characters are digits.
- 2. Extract the 3-digit DDD code from positions 10 to 12.
- 3. If DDD >= 500: female driver; subtract 500 to get base value.
- 4. If DDD < 500: male driver; base value equals DDD.
- 5. Month = Math.floor(base / 40) + 1.
- 6. Day = base % 40.
- 7. Validate decoded day and month against calendar limits.
- 8. For Florida licences (13 characters), verify final digit is strictly "0".