Military dog tags contain a compact set of identifying information, and reading them correctly depends on when and by which branch they were issued. Whether you’ve inherited a relative’s tags, found a set at an estate sale, or want to trace a veteran’s service, the markings on the tag itself are your starting point. Each line follows a specific format that changed over the decades as the military updated its identification systems.
What Each Line on a Dog Tag Means
The standard information stamped on a dog tag includes the service member’s name, an identification number, blood type, branch of service, and religious preference. But the exact layout varies by era and branch. A WWII-era tag, for example, was stamped with name, rank, service number, blood type, and religion. Early WWII tags also included a next-of-kin name and address, plus a “T” indicating a tetanus vaccination, but both were phased out by the 1950s.
Modern Marine Corps tags follow a four-line format where line four includes “USMC” alongside the Marine’s gas mask size. Army tags after 2015 replaced Social Security numbers with a Department of Defense identification number. If you’re looking at a tag and see a seven- or eight-digit number, it’s likely a service number from before 1969. A nine-digit number is a Social Security number. A ten-digit number is the newer DoD ID.
How the ID Number Tells You the Era
The single most useful clue on a dog tag is the identification number, because the military changed its numbering system at specific, documented dates. Before July 1, 1969, the Army and Air Force used unique service numbers assigned at enlistment. The Navy and Marine Corps continued using service numbers until January 1, 1972, and the Coast Guard held out until October 1, 1974.
After those dates, each branch switched to Social Security numbers. That means a Navy tag with a service number was issued before 1972, while an Army tag with a Social Security number dates to 1969 or later. Post-2015 Army tags use the DoD identification number instead, a change made to protect service members from identity theft.
Religious Codes and Other Markings
During World War II, only three religious codes appeared on tags: P for Protestant, C for Catholic, and H for Hebrew (Jewish). Over time, “No Religious Preference” and “None” were added. Today, service members can request virtually any faith designation, including Atheist, Agnostic, or even unconventional entries like Jedi or Druid.
WWI-era tags used similar letter codes for religion but had a much simpler layout overall. Early Army tags from 1906 were about the size of a half dollar and showed only name, rank, company, and regiment. By 1916, the Army added serial numbers. Navy tags from WWI included “U.S.N.” on the front, with enlisted sailors’ tags showing date of birth and enlistment, while officers’ tags showed date of appointment. The back of Navy tags even carried an etched fingerprint of the right index finger.
Marine Corps tags from WWII onward included a tetanus toxoid indicator formatted as “T” followed by a date, such as T-8/40. That marking was dropped in the early 1960s when serial numbers were also replaced by Social Security numbers.
The Notch on Older Tags
If you’re holding a WWII-era tag, you’ll notice a small notch cut into one end. The popular story is that medics placed the tag between a dead soldier’s teeth, using the notch to hold it in place. That may have happened in the field, but it wasn’t the original purpose. The notch was designed for a pistol-shaped imprinting machine called the Model 70 Addressograph, used by the Medical Department. A medic would insert the tag into the device, pull a trigger, and the stamped information would transfer through carbon paper directly onto a medical record. The notched tag is no longer issued.
Using a Dog Tag to Find Service Records
Once you’ve decoded the tag, you can use that information to request the veteran’s official military personnel file from the National Personnel Records Center (NPRC) in St. Louis. The key details you’ll need are the veteran’s full name as used in service, service number or Social Security number, branch of service, and approximate dates of service. Date and place of birth also help narrow the search. For records affected by the 1973 fire that destroyed millions of Army and Air Force files, additional details like place of discharge or last assigned unit can make the difference between finding a record and hitting a dead end.
Veterans and next-of-kin (defined as un-remarried spouse, parent, sibling, or child) can submit requests online through the eVetRecs system or by mailing a Standard Form 180 to the NPRC at 1 Archives Drive, St. Louis, MO 63138. Fax requests go to 314-801-9195. Federal law requires every request to be signed in cursive and dated within the last year.
If you’re a member of the general public with no family connection, access is limited. The NPRC can only release restricted information without the veteran’s or next-of-kin’s consent. The exception is archival records: personnel files 62 years or older have broader public access.
Can You Get Replacement Dog Tags?
Active-duty service members can get free replacements through the office that processes ID cards and Common Access Cards, or through their unit’s readiness center. For veterans, there is no official replacement program. The Army, Navy, Air Force, Marine Corps, and Coast Guard do not issue dog tags to former service members. You can request copies of discharge paperwork and other military records through the National Archives, but the physical tags themselves are not reproducible through government channels. Commercial companies will stamp replica tags to your specifications, but those are unofficial reproductions.