Most U.S. driver's licenses include both letters and numbers, and the letters carry specific meaning
Your driver's license number is not purely numeric. It contains letters, numbers, or both depending on which state issued it. The format varies widely — some states use a mix of letters and digits in a pattern that encodes information about you, while others use a random alphanumeric string that tells you nothing about the holder. A few states still use numbers only, though this is becoming rare.
The letters on your license are not random. In most states, they encode part of your name, date of birth, or both. This design serves two purposes: it makes the license harder to forge (because the letters follow a mathematical rule), and it lets officials verify the license is legitimate by checking whether the letters match the person's actual name and birth date.
The specific encoding system is called a check digit algorithm. The state generates letters and numbers from your personal information, then adds a final digit or letter that proves the sequence is valid. If someone alters the license, the check digit no longer matches, and the license fails verification.
Key Takeaways
- Most states encode your last name, first name, or birth date into the letters and numbers on your license using a mathematical formula.
- The final character on your license is usually a check digit or check letter that verifies the entire number is legitimate.
- Each state uses its own encoding system, so the same person's license looks completely different in different states.
- You cannot decode your own license number to find hidden information — the formula is designed to prevent that.
How states encode names and birthdates into license numbers
States that use alphanumeric licenses typically convert letters from your name into numbers, then arrange them in a pattern. For example, some states take the first three letters of your last name and convert them using a straightforward substitution (A=1, B=2, C=3, and so on). Others use the first and last letter of your last name plus the first letter of your first name.
Your date of birth often appears in the license number as well, usually in a compressed format. A state might use the last two digits of your birth year, the month, and the day — so someone born on March 15, 1987 might have "870315" embedded in their number. Some states rearrange these digits or use different date formats to make the pattern less obvious.
The exact formula is public information in most states, published in the state's driver's license manual or on the Department of Motor Vehicles website. However, knowing the formula does not let you decode someone else's license, because you would need to know their actual name and birth date to verify whether the letters match.
Why the check digit matters for verification
The last character on your license — often a letter or single digit — is the check digit. It is calculated from all the other characters using a mathematical formula. When a police officer, bank, or other official scans or reads your license, their system recalculates the check digit. If it does not match what is printed on the card, the license is flagged as invalid or altered.
This system catches forged licenses and altered numbers. Someone who tries to change their birth year or name on a license would have to recalculate the check digit correctly, which requires knowing the state's exact algorithm. Most forgers do not have access to that information, so their fake licenses fail verification when ready.
The check digit also protects against straightforward data-entry errors. If a clerk types your license number into a system and accidentally transposes two digits, the check digit will not match, and the system will prompt them to re-enter it.
States that use numbers only or random alphanumeric formats
A small number of states do not encode personal information into the license number at all. These states assign a random or sequential number to each license holder. In these cases, the license number tells you nothing about the person — you cannot extract their name, birth date, or any other information from the digits alone.
Some states have moved away from encoded numbers in recent years for privacy reasons. The logic is straightforward: if your license number does not contain your birth date or name, then someone who sees your license number cannot infer personal information about you. This reduces the risk if your license number is exposed in a data breach or seen by someone who should not have it.
You can find out whether your state encodes information by checking your state's DMV website or calling the DMV directly. They will tell you whether your license number is based on your personal information or assigned randomly.
How to verify your own license number is correct
You cannot easily verify your license number yourself without knowing your state's exact encoding formula and check digit algorithm. However, you can confirm that your license is valid by checking it against your state's DMV records.
If you believe your license number is wrong — for example, if it does not match what the DMV told you when you received it — contact your state's DMV directly. Bring your license and a form of identification. The DMV can look up your record and confirm whether the number on your card matches their system. If there is a mismatch, they can issue a corrected license.
If you are trying to verify someone else's license (for example, as a business owner checking a customer's ID), use your state's official license-verification system. Most states offer online verification tools that let you enter a license number and check whether it is valid and matches the person presenting it.
What happens if your license number changes
Your license number can change if you renew your license in most states. Some states issue a new number with each renewal, while others keep the same number for life. This depends on the state's policy and whether they have switched encoding systems over time.
If your state issues a new number at renewal, the old number becomes inactive. Any records tied to the old number (such as traffic tickets or vehicle registration) remain in the system, but new transactions use the new number. The DMV maintains a link between old and new numbers so that law enforcement and other agencies can find your complete history.
If you move to a different state, you will receive a new license number in the new state's format. The two states' DMVs can communicate to verify your driving record, but your license numbers will be completely different because each state uses its own encoding system.
Why you should not share your license number unnecessarily
Even though your license number encodes your birth date and possibly your name, you should treat it as sensitive information. Someone with your license number and the knowledge of your state's encoding formula could theoretically extract your birth date. Combined with your name (which may already be public), this information could be used for identity theft or fraud.
Only provide your license number when it is required — for example, when renting a car, opening a bank account, or responding to a law enforcement request. Do not post it on social media, include it in emails, or give it to businesses that do not have a legitimate reason to request it.
If your license number is exposed in a data breach, contact your state's DMV to report it. They can flag your record and monitor for fraudulent use. You may also want to place a fraud alert or credit freeze with the credit bureaus to prevent someone from opening accounts in your name.
Frequently Asked Questions
Can I figure out someone's birth date from their license number?
Only if you know their state's encoding formula and can verify the check digit. Even then, you would need to know which part of the number represents the birth date. Most people cannot do this without access to the state's DMV manual or technical documentation.
Do all states use the same license number format?
No. Every state has its own format, encoding rules, and check digit algorithm. A license number from California looks nothing like one from New York, even though both may contain letters and numbers.
What if my license number has a typo on it?
Contact your state's DMV with your license and proof of identity. They can verify whether the number on your card matches their records. If there is an error, they will issue a corrected license at no charge in most states.
Is my license number the same as my driver's license number?
Yes. The number printed on your driver's license is your driver's license number. It is the same number used in all official records, traffic citations, and vehicle registration systems.
Can I request a specific license number?
No. Your license number is assigned by the state based on their system. You cannot choose or customize it. Some states allow you to request a vanity license plate for your vehicle, but that is different from your driver's license number.