10 U.S.C. § 533 — Service credit upon original appointment as a commissioned officer

(a)(1) For deciding an officer's grade^* and rank^* when they get an original commissioned appointment (not warrant officer^*) in the Regular Army^*, Navy, Air Force, Marine Corps, or Space Force, that person gets credit at appointment for any active commissioned service they had before (not counting service as a commissioned warrant officer^*) — whether in any armed force, the National Oceanic and Atmospheric Administration, or the Public Health Service.
(2) The Secretary of Defense must write uniform rules letting the Secretary of the relevant military department limit how much of that prior service can be credited under paragraph (1), or deny credit entirely, for someone who is also getting "constructive service" credit under subsection (b).

(b)(1) Under Defense Department rules, when someone gets an original commissioned appointment (not warrant officer) and has advanced education, training, or special experience, the military department must credit them with constructive service as follows:
(A) One year of credit for each year of advanced education beyond a bachelor's degree, for jobs that require that advanced education or degree as a condition of the appointment. The Secretary caps this credit at the number of years most schools in that field require to finish that degree.
(B) (i) Credit for advanced education in a health field (other than medicine and dentistry) beyond a bachelor's degree, if the armed force will actually use that training directly. (ii) Credit for experience in a health field (other than medicine or dentistry), if the armed force will actually use that experience directly.
(C) Extra credit: (i) up to one year for an internship or similar required medical, dental, or professional training; and (ii) up to one year for each extra year of that graduate-level training or experience needed for a specialty the armed forces^* require.
(D) Extra credit: (i) for special training or experience in a field the Secretary names, if it's tied to the armed force's operational needs; (ii) during fiscal years 2021 through 2025, for advanced education in a field the Secretary names for the same reason.
(E) Extra credit for experience as a physician or dentist, if appointed as a medical or dental officer^* in the Army or Navy, or in the Air Force with the aim of becoming one.
(2) The total constructive service credited under this subsection cannot be more than what's needed to be eligible for an original appointment as a colonel (Army, Air Force, Marine Corps, Space Force) or captain (Navy).
(3) This constructive service credit adds to, not replaces, any credit given under subsection (a), and is given at the time of the original appointment.

(c) Constructive service credited under subsection (b) can only be used for: (1) the officer's starting grade as a regular officer; (2) rank within that grade; and (3) time in grade for promotion eligibility.

(d)(1) An officer cannot get constructive service credit under subsection (b) for education, training, or experience gained while already serving as a commissioned officer^* (not warrant officer) on active duty^* or active status^*. Exception: if an officer finishes advanced education or an advanced degree while on active duty faster than the normal time it takes, they can get credit under subsection (b)(1)(A) for the difference between the normal time and the time they actually took.
(2) A graduate of the U.S. Military Academy, Naval Academy, or Air Force Academy cannot get credit under this section for anything before graduating from that academy.

(e) If the Secretary of Defense decides the Army, Navy, Air Force, or Marine Corps has a critical shortage of qualified judge advocates on active duty below the rank of major or lieutenant commander, the Secretary may let the relevant military Secretary give extra constructive service credit — on top of any credit under subsection (b)(1) — to someone getting an original appointment as an Army or Navy judge advocate, or an Air Force or Marine Corps officer headed for that role. The extra credit is set so the person ends up with the grade of captain (or lieutenant, for Navy), ranked junior to every other officer already on active duty in that same grade.

(f) A reserve officer (not warrant officer) who gets an original appointment as a regular officer (not warrant officer) in the Regular Army, Navy, Air Force, Marine Corps, or Space Force:
(1) if they were on the active-duty list^* right before that appointment, keeps the same grade and date of rank they had on that list; and
(2) if they were not on the active-duty list right before that appointment, gets the grade and date of rank they would have had if they had been on the active-duty list on the day of the appointment.