Service number (United States Armed Forces)

Service numbers were used by the United States Armed Forces as the primary means of service member identification from 1918 until 1974. 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.

Each branch of the military service had its own version of service numbers. In order by year of creation, these were:

The following are the original service numbers which were first issued to United States military personnel:

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

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.

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