How do enlisted ranks in the military work?

I'm curious about the different ranks for enlisted personnel in the military. How do they vary, and what are the responsibilities at each level? I'm trying to understand how advancement works if I consider enlisting.

Military ranks can be broadly categorized into officer ranks and enlisted ranks. Since your question pertains to enlisted ranks, I'll focus on that.

Enlisted ranks are the initial ranks that individuals receive when they join the military service. These ranks signify the level of responsibility and leadership maintained by the service member, and they vary across different branches of the military, each having its own structure. Here's a general overview:

1. Private ranks / Seaman Recruit: Most personnel begin at the lowest level, labeled variously across branches - Private, Airman Basic, or Seaman Recruit. These personnel primarily focus on training and familiarization with military life.

2. Non-commissioned officers (NCOs) / Petty Officers: As enlisted personnel advance, they become non-commissioned officers (Army, Air Force, and Marine Corps) or Petty Officers (Navy and Coast Guard), holding ranks such as Sergeant or Petty Officer Second Class. These members have more experience and hence more responsibilities, including direct supervision over lower-ranking enlisted personnel.

3. Senior Non-commissioned Officers / Chief Petty Officers: At the top of the enlisted ranks are the senior non-commissioned officers (such as Master Sergeant, First Sergeant) and Chief Petty Officers. These are experienced enlisted service members who hold significant leadership responsibilities.

Promotions in rank are conditional on a variety of factors, including time spent in service, time spent at a certain rank, performance evaluations, and availability of a higher rank opening. Each promotion comes with additional responsibilities and duties, increases in pay grade, and allows for further professional growth within the armed forces. Enlisted personnel can also transition to officer roles later in their careers given certain qualifications like completing a Bachelor's degree.