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.

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” (Died Non-Battle) 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

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

85 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.

      • I got my fathers Navy records dating back to 1902 from here. You can submit the info online and when they find how pages it is they will send you the cost which you have pay before they send the copies. I does take time but well worth it.

  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.

    • FR indicates a reserve officer, using a system adopted after WW2 and Korea. In the late 1960s, the serial numbers were replaced with the Social Security Number.

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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.

    • The NARA database list the serial number to a Raymond M McDaniel, from Madison County, enlisted 7-31, 1945 at Indianapolis. Born 1926, Indiana native. Hope this helps.

  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.

    • Hi Doug. There are records you can obtain to learn more about his service. If you have a unit it, it is easier to locate information if his OMPF (service file) burned. You can learn more about research on my website http://wwiirwc.com and I do take clients if you need help. My book on research is listed at the end of the article too.
      Jennifer

  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.

    • If your dad was discharged from the Marines prior to 1955, his OMPF is available. Just request it through NPRC in St. Louis. It is open to anyone to request and will be complete (not affected by the fire.)

  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!

  24. Hi Amy,

    I am doing some research on my granduncle, George Donovan who fought for the US in the Pacific during WWII. I came across your site and was delighted to find out that there was an explanation to his Army Serial Number. You explained the first two numbers but was there a method for the other six or were they just a random selection?

    George’s Army Serial Number was 32443804 – meaning he was drafted (not enlisted) in New York??

    Would it then be right to say he was conscripted or is being drafted / inducted different to conscription?

    Thanks.

    • I believe the term would be drafted. I don’t think there is a difference, technically, but I’ve never heard “conscripted” used in WWII records.

  25. Hi Amy, Wile digging around the California desert I found a dog tag. And I have not been able to find any thing on this person. This dog tag list his next of kin in Los Angeles ? Any help would be grate. Ernest A. Daniels. W-2124233

  26. I have several relatives who enlisted in the Army during WW2 and according to this serial number breakdown they were drafted (3)… that cannot be because they lied about their age in order to join. Even a couple of old timers from the VFW have (3) as a first number and I know for a fact they enlisted. I would double check that coding information.

    • Thanks for you comment, Duke. This information came directly from the War Department’s publication “World War II Honor List of Dead and Missing” (June 1946), available on Fold3. Here is the part referring to the number 3: service number information. I don’t know why they would have a number that begins with 3 if they enlisted, rather than were drafted.

  27. Something is off with your military serial number decoding.

    My father retired from the USAF in 1961 as a major. His name was Wilson Reid Lowther and his serial number was AO 860517.

    If you do a search on the web, you can find his name and this serial number I memorized as a youth, and his name on the USAF retirement rolls.

    According to your article, he would have been a member of the WAC!

    To verify that I have his serial number correct, you can find him listed here:

    https://archive.org/stream/airforceregiste1962wash_0/airforceregiste1962wash_0_djvu.txt

    So the question is, why the discrepancy?

    • The numbering system noted here was specifically for the US Army, not the Air Force. Also, I do not know how long after the war this system stayed in place.

  28. hi – my grandfather was in the Army (823rd tank destroyer battalion), i have his dog tag with serial number 01824704 however I can’t seem to find any information on him in any online search. I see above that those that started with a 0 might have enlisted prior to WWII, but to my knowledge that was not the case with him. Any guidance would be appreciated!

  29. additionally, does your serial number ever change? He was promoted to 1st Lt., and eventually Captain, could that be why I am struggling to track any information down?

  30. I wish I could find some information about a WWII helmet I took possession of recently. There is more history to the purchase but I would hope to find information so I can figure everything out. It has a name inside “Dennis FW” with a number 14289011. Any help at all would be great. I really appreciate it. Thank you.

  31. Hello – My Uncle enlisted in WW2 in January of 1943– I have found what could be his enlistment record and it notes his Army serial number as 11072989. Would his serial number have changed if he entered the Air Corps (then part of the army) and became an officer? Later in the war he listed as a witness on a missing air crew report and his serial number is noted as O-815234. Thanks in advance for any light you can shed on this mystery!

  32. Hello Mrs ,I try to find more about my Maternal Granfather from Cook County Illinois ,enlisted in 1943 in Chicago Illinois how served in the ETO as a 405 Clerk Typist in the HQ HQ SQ 302 Transport Wing as a Sgt .When i try to find him in the Nara AAD they can find him .They tall me his records burned in the Nara Fire in 1973 .But i doubt it sens my mother and my US Aunt in Ca had his Honorable discharge from the AAF in 1946 .So do you know eventualy if by is Army Serial Number i can know more about him sens the few i know about him .His serial Army Number is 36-651-850 just in case you know ? .Best regards .Patrick Leullier From Normandy France

    • That seems too long to be a WWII US Army serial number. Do you know anything about the person’s service? (What war, branch of service, etc?)

      • Those numbers are on the request for monument. Yes he served as 1st Lt. 336 Fighter Sqd. 4th Fighter Group. I have his enlisted paper and request for monument a few pictures but can not find anything else. He served in the Air Corp. James Marshall Hall. Any help would greatly be appreciated. DOB: 28 July 1924. Thank you so much for your assistance. One paper has only 0 -2068660. Very confusing.

        • I suspect that the original number is O-2068660. In which case, the O (letter O,not a zero) denotes that he was a male commissioned officer and the 2 denotes that he enlisted or was drafted from Delaware, New Jersey, or New York.

          • I did not know they drafted from states other than where they were born. Very interesting. Thanks

          • The draft is going to be based on where they registered, which may or may not be the same as where they were born. The number in the serial number just groups states together; it doesn’t have any bearing on birthplace.

        • Hi, Chanetta. Just a little info on The 336th, they were SAC (Strategic Air Command) and the 4th was TAC (Tactical Air Command). Seymour Johnson AFB, NC. I was stationed there in the late 1980’s.
          Here’s a little info on the O and AO for some.

          Service Number Code Branch of Service Prefix/Suffix Meaning
          AO Army & Air Force Prefix First used by the Army Air Corps to denote Regular Army officers who were qualified in aviation. Later used by the Army Air Forces (and eventually the Air Force Reserve) to denote reserve officers.
          O Army Prefix Originally used by Regular Army officers prior to World War II.

  33. Hey there, I are across my Grandfathers ASN but can’t seem to find him anywhere online. Would you be able to help at all. I know he was part of the United States Army Air Corps and his ASN is 16032820. Name: Walter Thomas McGee. Please any information would help us. Thank you!

  34. hi amy, i am trying to find out information about the service of my grandfather in ww2. i know he was at monte casino, anzio, and north africa. he received a purple heart at anzio. i have his serial number and am interested in finding out what unit he was with. i would like to research them more. can’t find any way on line of connecting his serial number to his company or unit or battalion. thanks for any help you may have and for reading this.

    • You can’t determine the unit from the serial number (though it can be helpful to verify that you have the right person if you do see that information together somewhere). Are there any letters home from when he was in the service? The envelope could have the information.

  35. Hi Amy,

    What do seven digit serial numbers starting with 6 or 7 imply?
    I am looking at a company roster from 1944 which has at least 4 enlisted men with this style of serial number.
    The ones I have checked so far in NARA i need to add a zero at the front to make it an eight digit # but i have not spotted any obvious explanation for the shorter #

  36. Hi Amy – bringing this back to this thread. I have my grandfathers John E. Barron serial number (01824704) and have a bronze star medal of his. I also have the ribbons for what look like 2 Silver Stars and his Purple Heart (I don’t have these medals). I was trying to search online for listings of Silver Star, Bronze Star, and Purple Heart recipients, and I can’t find him anywhere. He was in the Army (823rd Tank Destroyer Battalion) during WWII. Any advice? Thank you

  37. Wow. Just ran across your website and wanted to say thanks for helping all these folks. You apparently are one busy lady. Hope to do some research on family wwii vets when I retire in a few years. Hope you will still be available for guidance then

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