# Service number (United States Armed Forces)

Service numbers were used by the United States Department of Defense as the primary means of service member identification from 1918 until 1974 (and before 1947 by the U.S. Army and U.S. Navy). Service numbers are public information available under the Freedom of Information Act, unlike social security numbers which are protected by the Privacy Act of 1974.

## Usage

Each branch of the military service had its own version of service numbers. In order by year of creation, these were:
* United States Army service numbers (1918)
* United States Navy service numbers (1920)
* United States Marine Corps service numbers (1920)
* United States Coast Guard service numbers (1921)
* United States Air Force service numbers (1948)
The following are the original service numbers which were first issued to United States military personnel:
* R-1: Arthur Crean – First service number of the United States armed forces
* O-1: John J. Pershing – First officer service number of the United States Army
* 100 00 01: Clayton Aab — First enlisted service number of the United States Navy
* 532 – Samuel R. Colhoun — Earliest recorded officer service number of the United States Navy
* 01 – James Ackerman – First officer service number of the United States Marine Corps
* 20001 – Alexander Schott — First enlisted service number of the United States Marine Corps
* 1000 – Joseph F. Farley – First officer service number of the United States Coast Guard
* 100000 – Mason B. Herring — First enlisted service number of the United States Coast Guard
* 4A: Hoyt Vandenberg – Earliest recorded officer service number of the United States Air Force
The original Air Force enlisted force was composed of personnel formerly of the United States Army Air Forces who continued to use their Army service numbers upon transfer to the Air Force in 1947. Thus, there is no established "first" enlisted service number of the U.S. Air Force since thousands of airmen simultaneously transferred into the Air Force on 18 September 1947.
Service numbers were eventually phased out completely by the social security number; the Army and Air Force converted to social security numbers on 1 July 1969, the Navy and Marine Corps on 1 January 1972, and the Coast Guard on 1 October 1974. Since that time, social security numbers have become the de facto military service number for United States armed forces personnel.
Beginning in 2002, the military began a further effort to protect the use of social security numbers, even within the military itself. New regulations declared that on all but the most official of documents (such as a DD Form 214 or evaluation reports) social security numbers would only list the last four digits. Regulations also were enacted to redact the social security number of reporting seniors (which were written in their entirety) on the personal copies of evaluation reports given to service members. The reason for this was to prevent possible identity theft issues committed by service members who had received a bad evaluation or who were disgruntled with their commanding officer.

## Format

The general design of United States service numbers was created first by the United States Army and later adapted by the other branches of the armed forces. Between each branch, service numbers are assigned differently while some branches make a conscious effort to separate officer and enlisted numbers while others do not. It is therefore common in the U.S. service number system for officers and enlisted personnel to perhaps hold the same service number and even more common for service members from different branches to be assigned the same number as well.
The Army is the only branch of service to begin both officer and enlisted service numbers at No. 1. Marine Corps officer numbers also begin at No. 1 but Marine Corps enlisted numbers start much later at #20,001. There is also no service No. 1 in the Navy, Coast Guard, or Air Force although the earliest recorded Air Force officer number was No. 4.
The entire range of United States service numbers extends from 1 to 99,999,999 with the United States Army and Air Force the only services to use numbers higher than ten million. A special range of numbers from one to seven thousand (1–7000) was also used by the United States Air Force Academy for assignment only to cadets and was not considered part of the regular service number system. Another unique service number series was the National Guard which used service numbers solely in the range of twenty to twenty nine million (20,000,000 – 29,999,999).
| Service Number | Army Enlisted | Army Officer | Navy Enlisted | Navy Officer | Air Force Enlisted | Air Force Officer | Marine Enlisted | Marine Officer | Coast Guard Enlisted | Coast Guard Officer |
| 1–100 | World War I enlisted personnel | World War I officers | Not issued | Not issued | Not issued | Senior Air Force officers formerly of the Army Air Forces | Not issued | World War I officers | Not issued | Not issued |
| 101–500 | World War I enlisted personnel | World War I officers | Not issued | Not issued | Not issued | Senior Air Force officers formerly of the Army Air Forces | Not issued | USMC Officers (1920s) | Not issued | Not issued |
| 501–1000 | World War I enlisted personnel | World War I officers | Not issued | Navy Officers (1920) | Not issued | Senior Air Force officers formerly of the Army Air Forces | Not issued | USMC Officers (1920s) | Not issued | Not issued |
| 1001–2000 | World War I enlisted personnel | World War I officers | Not issued | Navy Officers (1920s – 1930s) | Not issued | Senior Air Force officers formerly of the Army Air Forces | Not issued | USMC Officers (1930–1941) | Not issued | Regular USCG Officers (1921–1974) |
| 2001 – 10,000 | World War I enlisted personnel | World War I officers | Not issued | Navy Officers (1920s – 1930s) | Not issued | Senior Air Force officers formerly of the Army Air Forces | Not issued | USMC Officers (World War II) | Not issued | Regular USCG Officers (1921–1974) |
| 10,001 – 20,000 | World War I enlisted personnel | Regular Army officers (1920s/1930s) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1920s – 1930s) | Not issued | Senior Air Force officers formerly of the Army Air Forces | Not issued | USMC Officers (World War II) | Not issued | Regular USCG Officers (1921–1974) |
| 20,001 – 30,000 | World War I enlisted personnel | Regular Army officers (1920s/1930s) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1920s – 1930s) | Not issued | Regular USAF Officers (1948–1969) | Retroactive (1905–1917) | USMC Officers (World War II) | Not issued | Reserve/Warrant USCG Officers (1921–1950s) |
| 30,001 – 50,000 | World War I enlisted personnel | Regular Army officers (1940s/1950s) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1920s – 1930s) | Not issued | Regular USAF Officers (1948–1969) | Retroactive (1905–1917) | USMC Officers (World War II) | Not issued | Reserve/Warrant USCG Officers (1921–1950s) |
| 50,001 – 60,000 | World War I enlisted personnel | Regular Army officers (1940s/1950s) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1920s – 1930s) | Not issued | Regular USAF Officers (1948–1969) | Not issued | USMC Officers (1948–1966) | Not issued | Reserve/Warrant USCG Officers (1921–1950s) |
| 60,001 – 70,000 | World War I enlisted personnel | Regular Army officers (1950s/1960s) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1920s – 1930s) | Not issued | Regular USAF Officers (1948–1969) | Retroactive (1905–1919) | USMC Officers (1948–1966) | Not issued | Non-Regular USCG Officers (1950s/1960s) |
| 70,001 – 80,000 | World War I enlisted personnel | Regular Army officers (1950s/1960s) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1920s – 1930s) | Not issued | Regular USAF Officers (1948–1969) | Retroactive (1905–1919) | USMC Officers (1948–1966) | Not issued | Non-Regular USCG Officers (1960s/1970s) |
| 80,001 – 90,000 | World War I enlisted personnel | Regular Army officers (1950s/1960s) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1920s – 1930s) | Not issued | Regular USAF Officers (1948–1969) | Retroactive (1905–1919) | USMC Officers (1948–1966) | Not issued | "Special Use" service numbers |
| 90,001 – 99,999 | World War I enlisted personnel | Regular Army (Late 1960s) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1920s – 1930s) | Not issued | Regular USAF Officers (1948–1969) | Retroactive (1905–1919) | USMC Officers (1948–1966) | Not issued | "Special Use" service numbers |
| 100,000 – 125,000 | World War I enlisted personnel | Regular Army (Late 1960s) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1920s – 1930s) | Not issued | Not issued | USMC Enlisted (1920–1935) | USMC Officers (1966–1972) | USCG Enlisted (1920s/1930s) | Not issued |
| 125,001 – 140,000 | World War I enlisted personnel | Regular Army (Late 1960s) | B" & "D" Series Numbers (1965–1971) | Navy Officers (World War II) | Not issued | Not issued | USMC Enlisted (1920–1935) | Not issued | USCG Enlisted (1920s/1930s) | Not issued |
| 140,001 – 150,000 | World War I enlisted personnel | Officer Reserves (1920s – 1941) | B" & "D" Series Numbers (1965–1971) | Navy Officers (World War II) | Not issued | Not issued | USMC Enlisted (1920–1935) | Not issued | USCG Enlisted (1920s/1930s) | Not issued |
| 150,001 – 200,000 | World War I enlisted personnel | Officer Reserves (1920s – 1941) | B" & "D" Series Numbers (1965–1971) | Navy Officers (World War II) | Not issued | Not issued | USMC Enlisted (1920–1935) | Not issued | Retroactive Service Numbers | Not issued |
| 200,001 – 255,000 | World War I enlisted personnel | Officer Reserves (1920s – 1941) | B" & "D" Series Numbers (1965–1971) | Navy Officers (World War II) | Not issued | Not issued | USMC Enlisted (1936–1941) | Not issued | USCG Enlisted (World War II) | Not issued |
| 255,001 – 350,000 | World War I enlisted personnel | Officer Reserves (1920s – 1941) | B" & "D" Series Numbers (1965–1971) | Navy Officers (World War II) | Not issued | Not issued | USMC Enlisted (1936–1941) | Not issued | USCG Enlisted (1945–1962) | Not issued |
| 350,001 – 500,000 | World War I enlisted personnel | Officer Reserves (1920s – 1941) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1945–1955) | Not issued | Not issued | USMC Enlisted (Early World War II) | Not issued | USCG Enlisted (1962–1974) | Not issued |
| 500,001 – 600,000 | World War I enlisted personnel | Officer Reserves (1942–1954) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1945–1955) | Not issued | Not issued | USMC Enlisted (Early World War II) | Not issued | USCG Enlisted (World War II) | Not issued |
| 600,001 – 671,000 | World War I enlisted personnel | Officer Reserves (1942–1954) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1955–1963) | Not issued | Not issued | USMC Enlisted (Early World War II) | Not issued | USCG Enlisted (World War II) | Not issued |
| 671,001 – 700,000 | World War I enlisted personnel | Officer Reserves (1942–1954) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1964–1969) | Not issued | Not issued | Not issued | Not issued | USCG Enlisted (World War II) | Not issued |
| 700,001 – 800,000 | World War I enlisted personnel | Officer Reserves (1942–1954) | B" & "D" Series Numbers (1965–1971) | Navy Officers (1964–1969) | Not issued | Not issued | USMC Female Enlisted | Not issued | USCG Enlisted (World War II) | Not issued |
| 800,001 – 1,000,000 | World War I enlisted personnel | Special Duty Officers (1921–1969) | B" & "D" Series Numbers (1965–1971) | Not issued | Not issued | Not issued | USMC Enlisted (Mid World War II) | Not issued | USCG Enlisted (World War II) | Not issued |
| 1,000,001 – 1,700,000 | World War I enlisted personnel | Army Officers (1942–1954) | Enlisted Series 100 (Retroactive) | Not issued | Not issued | Not issued | USMC Enlisted (1943–1953) | Not issued | Not issued | Not issued |
| 1,700,001 – 1,800,000 | World War I enlisted personnel | Army Officers (1942–1954) | Enlisted Series 100 (Retroactive) | Not issued | Not issued | Not issued | USMC Female Enlisted | Not issued | Not issued | Not issued |
| 1,800,001 – 2,000,000 | World War I enlisted personnel | Army Officers (1942–1954) | Enlisted Series 100 (Retroactive) | Not issued | Not issued | Early Air Force Reserve | USMC Enlisted (1953–1965) | Not issued | Not issued | Not issued |
| 2,000,001 – 2,800,000 | World War I enlisted personnel | Army Officers (1942–1954) | Enlisted Series 200 (1920–1971) | Not issued | Not issued | Not issued | USMC Enlisted (1966–1972) | Not issued | USCG Enlisted (1948–1974) | Not issued |
| 2,800,001 – 2,999,999 | World War I enlisted personnel | Army Officers (1942–1954) | Enlisted Series 200 (1920–1971) | Not issued | Not issued | Not issued | Not issued | Not issued | USCG Enlisted (1948–1974) | Not issued |
| 3,000,000 – 3,999,999 | World War I enlisted personnel | Warrant officers (1957–1969) | Enlisted Series 300 (1920–1971) | Not issued | Not issued | Air Force officers (1948–1969) | Not issued | Not issued | World War II (Special Duty) | Not issued |
| 4,000,000 – 4,999,999 | World War I enlisted personnel | Army officers (1954–1957) | Enlisted Series 400 (1920–1971) | Not issued | Not issued | Not issued | Not issued | Not issued | Female enlisted (1942–1945) | Not issued |
| 5,000,000 – 5,999,999 | World War I enlisted personnel | Army officers (1957–1969) | Enlisted Series 500 (1920–1971) | Not issued | Not issued | Not issued | Not issued | Not issued | Special Duty enlisted (1942) | Not issued |
| 6,000,000 – 6,999,999 | Army enlisted (1919–1941) | Not issued | Enlisted Series 600 (1920–1971) | Not issued | Not issued | Not issued | Not issued | Not issued | World War II (Special Duty) | Not issued |
| 7,000,000 – 7,100,000 | Army enlisted (1919–1941) | Not issued | Enlisted Series 700 (1920–1971) | Not issued | Not issued | Not issued | Not issued | Not issued | USCG Enlisted (1943–1945) | Not issued |
| 7,100,001 – 7,999,999 | Not issued | Not issued | Enlisted Series 700 (1920–1971) | Not issued | Not issued | Not issued | Not issued | Not issued | USCG Enlisted (1943–1945) | Not issued |
| 8,000,000 – 8,999,999 | Female enlisted (1948–1969) | Not issued | Enlisted Series 800 (1920–1971) | Not issued | Female enlisted (1948–1969) | Not issued | Not issued | Not issued | Not issued | Not issued |
| 9,000,000 – 9,999,999 | Not issued | Not issued | Enlisted Series 900 (1920–1971) | Not issued | Not issued | Not issued | Not issued | Not issued | Not issued | Not issued |
| 10,000,000 – 10,999,999 | Regular Army (Enlisted Extra-US) | Not issued | Not issued | Not issued | Regular Air Force | Not issued | Not issued | Not issued | Not issued | Not issued |
| 11,000,000 – 19,999,999 | Regular Army | Not issued | Not issued | Not issued | Regular Air Force | Not issued | Not issued | Not issued | Not issued | Not issued |
| 20,000,000 – 29,999,999 | Army National Guard | Not issued | Not issued | Not issued | Air National Guard | Not issued | Not issued | Not issued | Not issued | Not issued |
| 30,000,000 – 30,999,999 | World War II draftees (Extra-US) | Not issued | Not issued | Not issued | WWII crossover #s | Not issued | Not issued | Not issued | Not issued | Not issued |
| 31,000,000 – 39,999,999 | World War II draftees | Not issued | Not issued | Not issued | WWII crossover #s | Not issued | Not issued | Not issued | Not issued | Not issued |
| 40,000,000 – 49,999,999 | Special duty enlisted | Not issued | Not issued | Not issued | WWII crossover #s | Not issued | Not issued | Not issued | Not issued | Not issued |
| 50,000,000 – 59,999,999 | Army draft force (P-WWII) | Not issued | Not issued | Not issued | Air Force draft force (1948–1966) | Not issued | Not issued | Not issued | Not issued | Not issued |
| 60,000,000 – 69,999,999 | Army draft force (Late 1960s) | Not issued | Not issued | Not issued | Air Force draft force (1966–1969) | Not issued | Not issued | Not issued | Not issued | Not issued |
| 70,000,000 – 89,999,999 | Not issued | Not issued | Not issued | Not issued | Not issued | Not issued | Not issued | Not issued | Not issued | Not issued |
| 90,000,000 – 99,999,999 | Philippine Army Augments (WWII) | Not issued | Not issued | | Not issued | | Not issued | Not issued | | Not issued |

## Prefix and suffix codes

Service number prefix and suffix codes were one and two letter designators written before or after a service number; a service member could only have one code at any given time. The purpose of these codes was to provide additional information regarding a military service member with the very first prefix codes created by the Army in 1920 and greatly expanded over the next thirty years. The Navy created the first suffix code "W", written after the service numbers of female enlisted personnel, but it was the Air Force that made the greatest use of suffix codes until 1965 when the Air Force switched to using prefixes. Some prefix and suffix codes were also re-introduced, with different meanings, by various branches of military. In the modern age, the only code that survives is the suffix code "FR", written after the social security numbers of Regular Air Force personnel.
| Service Number Code | Branch of Service | Prefix/Suffix | Meaning |
| A | Army & Air Force | Prefix & Suffix | As a prefix, used by members of the Women Army Corps. As a suffix, used by Regular Air Force officers until 1965. |
| AA | Air Force | Prefix | Used by personnel of the "Women in the Air Force" (WAF) |
| AD | Air Force | Prefix | Used by Air Force aviation cadets |
| AF | Air Force | Prefix | Used by male Air Force enlisted personnel |
| 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 |
| AR | Air Force | Prefix | Used by Air Force dieticians |
| AW | Air Force | Prefix | Used by Air Force warrant officers |
| B | Navy | Prefix | Used between 1965 and 1971 as part of the "B-Series" enlisted service numbers |
| D | Navy | Prefix | Used between 1969 and 1971 as part of the "D-Series" enlisted service numbers |
| E | Air Force | Suffix | Used by male Air Force warrant officers until 1965 |
| ER | Army | Prefix | Used by enlisted members of the Army Reserve |
| F | Army | Prefix | Used by field clerks during the First World War |
| FG | Air Force | Prefix | Used by officers and warrant officers of the Air National Guard |
| FR | Army & Air Force | Prefix & Suffix | Used briefly as an Army prefix by some enlisted members of the Army Reserve. Later used as an Air Force prefix for all officers and warrant officers of the Regular Air Force. After 1969, used as a suffix for Regular Air Force officers, written after the social security number. |
| FT | Air Force | Prefix | Used by Air Force officers and warrant officers who were without a component |
| FV | Air Force | Prefix | Used by Air Force Reserve officers and warrant officers |
| H | Air Force | Suffix | Used by female Air Force warrant officers until 1965 |
| K | Army & Air Force | Prefix & Suffix | As a prefix, used by female specialist officers with service numbers of 100,001 and higher. As a suffix, used by Air Force Academy cadets until 1965 |
| KF | Army | Prefix | Used female Regular Army officers |
| L | Army | Prefix | Used by enlisted members of the Women's Army Corps |
| MJ | Army | Prefix | Used by Occupational Therapist Officers |
| MM | Army | Prefix | Used by Physical Therapist Officers |
| MN | Army | Prefix | Used by male members of the Army Nurse Corps |
| MR | Army | Prefix | Used by Army enlisted dieticians |
| N | Army | Prefix | Used by female nurse officers |
| NG | Army | Prefix | Used by National Guard personnel |
| O | Army | Prefix | Originally used by Regular Army officers prior to World War II. In the 1960s, used by Army specialist officers. |
| OF | Army | Prefix | Used by male Regular Army officers |
| R | Army | Prefix | Originally used by Regular Army World War I enlisted personnel. In the 1960s, used by Army officer dieticians |
| RA | Army | Prefix | Used by Regular Army enlisted personnel |
| RM | Army | Prefix | Used by Regular Army enlisted personnel holding temporary commissions as warrant officers |
| RO | Army | Prefix | Used by Regular Army enlisted personnel holding temporary reserve officer commissions |
| RP | Army | Prefix | Used by retired Regular Army enlisted personnel upon recall to active duty |
| RV | Army | Prefix | Used by female warrant officers granted reserve commissioned officer billets |
| RW | Army | Prefix | Used by male warrant officers granted reserve commissioned officer billets |
| T | Army | Prefix | Used by flight officers appointed from an enlisted status |
| UR | Army | Prefix | Used by draft personnel who are later appointed officers in the Regular Army |
| US | Army | Prefix | Used by enlisted draft personnel of the Army of the United States |
| W | Army, Air Force, Navy, & Marine Corps | Prefix & Suffix | As a prefix, used by Regular Army Warrant Officers. Also used by female Regular Air Force officers and female Marine Corps enlisted personnel. As a suffix, used by Navy female enlisted personnel |
| WA | Army | Prefix | Used by enlisted members of the Women's Army Corps |
| WL | Army | Prefix | Used by female Regular Army personnel granted officer commissions in the Army Reserve |
| WM | Army | Prefix | Used by female Regular Army personnel granted warrant officer commissions in the Army Reserve |
| WR | Army | Prefix | Used by female enlisted reservists of the Women's Army Corps |