How to Decode a WWII US Army Serial Number

Gerald Ridenour, an Aviation Cadet in the U.S. Army Air Force, died in World War II. He was just shy of his 21st birthday. When my mom showed me his grave at Highland Cemetery in Perry County, Ohio, I knew I had to find out more about him.

The Casualty List

I found him listed on the WWII Army and Army Air Force Casualty List on Fold3. The information includes name, serial number, rank, and something pertaining to the death.

ridenour-casualty-list

From World War II Honor List of Dead and Missing: State of Ohio. Online at Fold3 (titled WWII Army and Army Air Force Casualty List).

It was when I looked for the meaning of “DNB” that I discovered there is meaning in the serial number, also referred to as a service number.

WWII US Army Serial Numbers: Meaning in the First Digits

The U.S. Army began issuing serial numbers to help avoid mixing the records of people with the same name. (A genealogist’s dream come true!)  When we dig a little deeper into the number itself, we can learn a bit about the person.

Look at the First Number or Letter

Some prefixes were used in World War I. However, the following system began shortly before World War II.

The first character gives us a lot of information.

  • 1 = Enlisted in the Army (in other words, volunteered rather than drafted)
  • 2 = Federally recognized National Guard
  • 3 = Drafted
  • 4 = Drafted
  • O (that’s the letter O, not a zero) = Male commissioned officers
  • W = Male Warrant officers
  • T = Flight officers (Army Air Force)
  • L = Commissioned officers of the Women’s Army Corps (WAC)
  • V = WAC Warrant officers
  • A = WAC enlisted women
  • R = Hospital dietitians
  • M = Physical therapy aides

Looking back at the casualty list, we now know:

  • Gerald Ridenour enlisted
  • Arthur Porter was in a federally recognized National Guard unit
  • Robert Pratt and Wilfred Ratliff were drafted
  • William Petruzzi was a commissioned officer. (We also knew that from him being listed as a 2 Lt. But if his rank hadn’t been listed, we would have discovered he was a commissioned officer based on his serial number.)

Look at the Second Number

When you have an 8-digit serial number, the second number shows the Service Command. This narrows down where the person enlisted or was drafted. If you have a serial number for a member of the WAC, look at the number after the letter prefix.

There’s an exception. Remember those serial numbers that begin with “2,” showing National Guard service? You need to look at the 3rd digit. (The second digit for those will always be a zero. You knew there’d be some exception, didn’t you.)

  • 1 = Connecticut Maine, Massachusetts, New Hampshire, Rhode Island, Vermont
  • 2 = Delaware, New Jersey, New York
  • 3 = Maryland, Pennsylvania, Virginia
  • 4 = Alabama, Florida, Georgia Mississippi, North Carolina, South Carolina, Tennessee
  • 5 = Indiana, Kentucky, Ohio, West Virginia
  • 6 = Illinois, Michigan, Wisconsin
  • 7 = Colorado, Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South Dakota, Wyoming
  • 8 = Arkansas, Louisiana, New Mexico, Oklahoma, Texas
  • 9 = Alaska, Arizona, California, Idaho, Montana, Nevada, Oregon, Utah, Washington
  • 0 = When the first number is 3, the zero means he was drafted outside the U.S. (301 indicates Panama; 302 indicates Puerto Rico)

Since the second digit of Gerald Ridenour’s serial number is 5, we now know that he enlisted from either Indiana, Kentucky, Ohio, or West Virginia. The same for where Robert Pratt and William Ratliff were drafted. Arthur Porter, from the National Guard, also enlisted from one of those four states, since the third number of his serial number is 5.

A Note About Twins

According to the introduction to the World War II Honor List of Dead and Missing:

“Serial numbers are assigned with great care and according to a set of regulations. Consecutive serial numbers, for example, are not assigned to twins since this might cause confusion of identity between two persons with the same birth date and same general physical characteristics.”

Other Resources

References

How to Decode WWII US Army Serial Numbers

World War II US Army serial numbers weren't random. This guide will show you what each part means.

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50 thoughts on “How to Decode a WWII US Army Serial Number

  1. This applies only to USA forces. Its heading should indicate this. There are family historians and WW 2 forces in many other countries !!

    • You’re exactly right, Ian. I have edited the title and the heading to better reflect that. My apologies for any confusion.

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  3. I have my grandfathers serial number and a record where he enlisted, but how can I find more about him? i.e., Where was he stationed, last known address, or other family members? After enlisting he became a ghost, my mother was born at the army hospital there but there is no record of that either. She did not know him and has been desperate to learn more! Maybe she has siblings!

    Your post helped to tell me that he was drafted, though! 🙂

    • Hi, Lacey! Glad you got at least some info from the post! Was this during WWII? Was the post in the US or overseas? If overseas, I think there’s a record group at the National Archives for births of American citizens abroad. Have you looked for your grandfather in the 1940 census? The reason I ask is if you find him there (hopefully still living at home), you might be able to track some of those people forward and see if he’s mentioned in any of their obituaries (which could give you another point in time for him, possibly even a location). Does your mother know what unit he belonged to? If so, look for reunion groups; many of them have message boards. Your mother could also do a DNA test to find some genetic relatives. It’s amazing what those tests can do in situations like this. Good luck!

    • have you tried the Military records archive in St. Louis. MO.? They lost a lot of records in a fire in 1976 but still have a lot. I got my father’s & his brothers full Army & Marine records from WW2. Also if you know the town he lived in you could see if they have a VFW there. They may have info too. They also have WW1 records, don’t know about any of the other wars.

  4. Can someone help me, please? I found an old draft registration card on my great great grandfather. It shows a letter U before a 3 digit serial number of 709, this was in 1942 but I have only the year not month or day. I’ve been trying to search for more information but I have no idea where I should even start looking.

    • The 1942 draft (AKA “the old man draft”) wasn’t a draft in the traditional sense. According to the National Archives, “This draft registration was not intended to be used for military service, but to provide a complete inventory of manpower resources in the United States that could be used for national service.” The serial number listed on these cards don’t indicate military service. My understanding is that the numbers on those cards have no intrinsic meaning, and were just a way to number the men who were listed.

  5. Thank you! Thanks to this I got to be able to read my grandpa and great uncle’s army serial numbers : ) I really appreciate this. They never talked about WW2 much around me since I was too little at the time and by the time I was old enough…they were gone so I’m trying my best to learn about them during that time.

  6. Quite an interesting posts. I can so envision you walking with your mom and she remembering the memories. The info on the serial number is new to me, so I quickly looked up my uncles and can know for sure he was drafted. You listed about the first two numbers, but does the other numbers signify anything also? I’ll be adding this into his story.

  7. researching family of a ww2 soldier. he has a 7 digit number. in the military list of casulties, only a few have 7 digits while most have 8. Help please.

      • Hi Amy, Thank you for this wonderful blog. I have encountered a few WWII Army service numbers over the years that are only 7 digits. It can indicate that the veteran enlisted prior to WWII. In the NARA AAD database, 7 digit service numbers are preceded by a zero, (to create an 8 digit number for the system.)

  8. A German crash site team recently found some aircraft parts and a Dr.’s ID bracelet near Aachen, Germany. It only says “Dr Franklin L. Wilson, O-486705”. I can’t find anything about him online, and he’s not listed as buried overseas on ABMC.org’s website. Can we tell where he was from using any of the numbers? I can then research WW2 deaths by state. They’d like to give it to him or his relatives. Thanks.

    • As far as I can tell, the 6-digit commissioned officer numbers (which is what the O prefix indicates) doesn’t tell the Army Area or Corps Area, which would narrow down where he was from. He isn’t listed in the Rosters of World War II Dead, 1939-1945 on Ancestry. Is it possible that Dr. Wilson didn’t die in the crash? If so, could he be the Franklin L. Wilson who is buried at Arlington National Cemetery? He was a Lt. Col. and served in both WWII and Korea. That would be consistent with your Dr. Wilson being a commissioned officer.

  9. Is there a way to buy your book on how to decode US Army serial numbers. I’d love to buy one. Thanks

  10. I have part of my father in laws parachute from WW2. the only numbers on it are 0-AC-42-48866. Is there any way to get information on it?

  11. I’ve got a watch that’s inscribed on the back Wm S. Davis O-1166953. Is there anywhere I can find additional information on the service number? I’d like to reunite his family with the watch if possible. Thanks.

    • Hi Paul. My volunteer research group might be able to help. We provide free research to help people return items to veterans. Can you email me, please? dogtag73 (at) gmail.com

  12. My father was stationed in Iceland in WW!!. I have his serial number, how can I find out what troop or unit he was with and where in Iceland he was stationed?

    • Hi, Deana! That’s cool that your dad was in Iceland! (Yes, the pun was intended 😉 ) Do you know where he was living when he came out of the service? When he was discharged, he should have filed his separation papers at the county courthouse. Those papers would list his unit. Do you have any papers related to a pension or anything regarding the VA? Those often include information like that.

  13. My great uncle died in France during WWII. I have his service number but can’t really find anything else on his death. I would really like to know the location where he died. Any ideas?

    • Hi Pam, if you haven’t been been able to find this information yet, I might be able to help you, but I’d need his name and service number to begin the research. If you’d prefer not to post it here, you can email me at dogtag73 (at) gmail.com

  14. My father enlisted in 1956 or 57 under the federal reserve act of 1955. He was given a serial number fr19556887. he was sent to Fort Ord then to Fort Chaffee. He has lost his dd-214 and we have tried everywhere to replace it but none of the sites recognize his serial number. Is this a true serial number ? and where can we go to get his records?

    • That is a great question — and one that I wish I knew the answer to. My suggestion would be to contact your county or state veterans affairs office and see if they can guide you. If your father is trying to get benefits, they likely have a counselor or ombudsman who can guide him through the process since he doesn’t have his DD214.

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  16. I have a helmet from WWll with the name R. Ms Daniel (no clue why there’s an “s” after the “M”, but its written on 2 places on the head band), service number 45018435. I’d like to get some info the soldier who wore it. I know he enlisted in Indiana, Kentucky, Ohio or West virginia. If you can email me with any info, I’d sure appreciate it.

  17. I know most everyone here appears to be discussing WWII but I have recently come across what I know as “dog tags” with a 7 digit number but also my grandfather’s name printed on the opposite side. Based on my grandfathers age he would have had to have been WWI. Could these be “dog tag”? If so is there a way I can get info on the number on the tag? Thank you for any help or advise.

  18. Hi Amy. My Great Uncle recently passed away and I’m trying to do a WWII trace of his travels. His serial number is 31229854. I know he was a private, a radio operator and served in the 3rd Army. That is about all. What are options to find out more? Thanks.
    Doug H.

  19. This was extremely helpful, and I do mean extremely. Thank you so much for writing this. Do you have an information as to where I can find serial number information like this for outside of the Us during WW2? Specifically Germany, but any information would be helpful. Thank you.

    • Hi, Debbie. I’m glad you found this post useful! I don’t have any information on how other countries set up their ID numbers. I would suggest contacting the national archives in the country you’re interested in and see if they can point you in the right direction. Good luck!

  20. hi – my dad was a WWII US Marine. he was born January 1914 (sorry I could never remember the date) in Detroit MI. he died in January 1998. Again I cannot remember the date. He lived in Saginaw, MI when he enlisted in the Marines in 1943.

    As for me, I joined the California Natl. Guard in 1956, while in high school, then joined the US Army in Sept. 1956 after graduating from high school. My serial number was RA28xxxxxx (not sure if I am supposed to show it).

    tried to find info about dad but could not.

    • Are you trying to find more about his military service? You might want to start with the Library of Michigan in Lansing. They have an extensive collection of military records of people from Michigan. Their website is http://seekingmichigan.org/ , which has links to their catalog and their contact information.

  21. I am trying to find my adopted Dads serial number. I found it online the other night but now I cant seem to find it. Can you please help me?

  22. Hi Amy, my Native American uncle was apparently in the Army
    During WW2. The military has no files on him. His name is Frank F. Iron Shooter, serial number 16015805 and I have no clue what to do next. Thank you.

  23. Amy, in regards to my uncle Frank I.S., while my mom was alive (she just passed at age 96 in March), we spoke of me trying to get him a military headstone. I cannot locate a dd214 because he had passed away in a house fire at home. Apparently his records were also in the fire in Missouri back when. I checked everywhere however seems like no one has any records on him. Even the big veterans records center say they can’t find any information on him. They say if I find something to let them know. So I am still looking. Thank you but if you have any helpful information I sure would appreciate it.

    • He should have filed a copy of his DD214 at the courthouse in the county where he lived when he was discharged. Have you contacted the veteran affairs office in that county? They might be able to point you in the right direction.

      • Yes I contacted the courthouse where he lived and also several local veterans offices. The genealogy place that he’s buried at has a copy of his serial number and that he enlisted in the army however that was decades ago and the new people don’t know anything about the source. I wrote to Missouri and they said just keep looking.
        Thank you though.

        • …. Also maybe he was not in the military? Or maybe he got discharged… My mom thought he was in the Coast Guard, but her memory was kind of poor. His adult children don’t even know… So there is a Twist to the story somewhere …..thanks!

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