What does DD mean on a driver’s license? The document number explained
DD stands for document discriminator, the number for the specific card you hold. Here’s where to find it, whether it changes and how it differs from your license number.
DD on a driver’s license stands for “document discriminator.” It’s a number that identifies the specific card you were issued, not you as a driver, so it is not the same as your driver’s license number.
That’s the short answer to “what does DD mean on a driver’s license?” The definition comes from the 2025 driver’s license and ID card design standard of the American Association of Motor Vehicle Administrators (AAMVA), which says the number “must uniquely identify a particular document issued to that customer from others that may have been issued in the past.” So a renewed or replacement card should get a new one. Below, we cover where to find it, how it differs from your license number and why businesses that check IDs look at it.
What does DD mean on a driver’s license?
DD is short for document discriminator, a field defined in the June 2025 edition of the AAMVA standard. That edition replaces the 2020 one and is the guide AAMVA says states should use when they develop new card designs. It lists the document discriminator as a mandatory field on both driver’s licenses and ID cards, with room for up to 25 letters, numbers or symbols.
What is the document number on a driver’s license?
The standard also says the number “may serve multiple purposes of document discrimination, audit information number, and/or inventory control.” Each state decides how to build it. Florida’s August 2020 retail guide describes its field 5 as “a unique number indicating issuance office, issue date and form number.”
One caution on wording: not every form that asks for a “document number” means the DD. If the instructions don’t say which number they want, ask whoever issued the form before you guess.
Where is the document number on a driver’s license?
On cards that follow the AAMVA standard, the DD is on the front, in the same block as your name, dates and license number. The standard requires a small reference number to be printed as text next to each field “to identify the data element,” so the quickest way to find the DD is to look for a 5:
- 1 — family name
- 2 — given names
- 3 — date of birth
- 4a — date of issue
- 4b — date of expiry
- 4d — customer identifier (your license number)
- 5 — document discriminator (DD)
Exact placement still varies by state. The Pennsylvania Department of Transportation (PennDOT) says its “DD” number sits at the bottom center of the license or photo ID card. Florida’s 2020 retail guide said every Florida license and ID card would show these small reference numbers.
Designs also change slowly. The 2025 standard expects many jurisdictions to keep issuing cards based on the 2020 edition for some time, and Florida, which began issuing a new design on September 30, 2026, says “all currently valid credentials will remain valid until they expire.” If you can’t find a DD on an older card, check your state department of motor vehicles (DMV) for a guide to its card designs.
Does the DD number on your license change?
Yes. Each new card should have its own DD. The AAMVA standard adds that “if the same number appears on more than one document it does not qualify as unique.” So a renewed, replaced or reissued card should carry a different DD from the card before it.
Your license number works differently. The standard calls it a “customer identifier,” and state guidance suggests it carries over from card to card. PennDOT suggests finding your license number on the old card you got back when you had your new photo taken. The Texas Department of Public Safety (DPS) says that when a stolen card has been used fraudulently, it will look at the situation “to determine if issuing a new number is necessary to protect you.”
The practical point: if a form asks for your DD or another card-specific number, read it from the card you hold now. The number on an older card won’t be the right one.
DD number vs. driver’s license number
Both numbers appear on the front of a standard-following card, but they do different jobs:
- Driver’s license number (field 4d). The standard defines the customer identifier as “the alphanumeric string assigned or calculated by the issuing authority.” Florida’s guide calls it the “ID/DL number.”
- Document discriminator (field 5). The number for one particular card. The standard gives “DD” as the abbreviation states can use to label it.
PennDOT puts it plainly: the DD number is not your driver’s license number, which in Pennsylvania is eight digits. Federal REAL ID rules require each compliant card to show a “unique driver’s license or identification card number” that cannot be your Social Security number. That rule is about the license number, not the DD.
Other numbers and marks you may see
- Audit information (reference 20) and inventory control number (reference 21). Both are optional in the AAMVA standard. Audit information shows “when, where, and by whom” a card was made, and the inventory control number is tied to the card stock and other materials. Florida’s 2020 guide places its inventory control number on the back of the card.
- The REAL ID star. According to the Transportation Security Administration’s (TSA) REAL ID FAQs, compliant cards carry an approved marking on the upper top portion of the card, and a card without one is not REAL ID-compliant. TSA notes that most enhanced driver’s licenses don’t carry the star, and that this is acceptable. The AAMVA standard describes the mark as a gold or black star in one of several styles and gives “NOT ACCEPTABLE FOR REAL ID OFFICIAL PURPOSES” as the preferred wording for non-compliant cards. TSA says REAL ID enforcement began on May 7, 2025.
Why you might be asked for your DD number
Some DMV online services ask for a number tied to your current card as an extra check. To replace a card online, Texas DPS asks for your license or ID number, your date of birth, the last four digits of your Social Security number and “the audit number from your most recently issued card.” It adds: “For security reasons, DPS cannot provide your audit number.”
A number printed only on your latest card is a reasonable way to confirm that the person filling in a form actually holds that card. For the same reason, treat the DD like the rest of your license data and avoid posting photos of your license online.
Why businesses that verify IDs care about the DD
Every card that follows the AAMVA standard must carry a two-dimensional barcode in a format called PDF417 on the back, and that barcode repeats much of what is printed on the front. The standard gives each barcode field a three-letter code, including:
- DAQ — customer ID number (the license number)
- DCF — document discriminator
- DCS — family name, and DAC — first name
- DBB — date of birth, DBD — issue date, and DBA — expiration date
The standard follows a principle of “harmonization” between printed and machine-readable data, “which means that there should be corresponding information.” It also admits that “at times the information is not identical.” Barcode dates, for example, are written without slashes, so a fair comparison normalizes formats first.
Comparing the two sides is a basic fraud check. The National Institute of Standards and Technology (NIST) identity proofing guidelines, SP 800-63A-4 (July 2025), say that when a barcode or machine-readable zone is present, automated document inspection “SHALL compare” that data to the printed data for consistency. A DD on the front that doesn’t match DCF in the barcode, or a name or date of birth that differs between the two, doesn’t prove fraud on its own. But it is exactly the kind of conflict covered in our deepfake red flags for account opening, and it deserves a closer look.
This is one reason to read both sides of the card in remote verification. In Securely Verify’s identity verification, the name, date of birth, document number and expiry are read from the card and from the barcode on U.S. driver’s licenses, and reviewers see the extracted data side by side with the images before they approve or reject. On Growth and higher plans, they can also request a retry.
If you want to see this with your own customers, start a 7-day free trial — 20 verifications, no card required.
Related guides
Sources: 2025 AAMVA DL/ID Card Design Standard (AAMVA, June 2025); Florida Driver License and ID Card Retail Guide (Florida Department of Highway Safety and Motor Vehicles (FLHSMV), August 2020); Florida Launches Newly Designed Driver Licenses and Identification Cards (FLHSMV, September 29, 2026); Where to Find Your Driver’s License/Photo ID Number (PennDOT, accessed October 2026); Replace your Driver License, Commercial Driver License or ID Card (Texas DPS, accessed October 2026); REAL ID FAQs (TSA, accessed October 2026); 6 CFR 37.17, Requirements for the surface of the driver’s license or identification card (Electronic Code of Federal Regulations (eCFR), current as of October 5, 2026); NIST SP 800-63A-4, Digital Identity Guidelines: Identity Proofing and Enrollment (NIST, July 2025). This article is general information, not legal or compliance advice.
