How do military rankings differ by branch?

Hello, I'm thinking about a possible future in the military after high school, and I'm trying to get a grip on how ranks and promotions work. I understand that each branch has its own rank structure. Could someone lay out the rank structure for all different branches? Is there a comparison or equivalence between ranks of different branches? Any help with this would be super useful, as I'm trying to figure out which path might be the best for me.

Sure, happy to provide a brief breakdown of the rank structures for the five main branches of the U.S military: Army, Navy, Air Force, Marines, and Coast Guard. There is also the newer branch, the Space Force, which has its rank structure, but it is similar to the Air Force.

Army, Air Force, and Marines

For the enlisted, the Army and Marines have almost identical ranks, with Private, Specialist, Corporal, and various levels of Sergeant, and the Air Force has Airman, Airman First Class, Senior Airman, and different levels of Sergeant.

For Officers, these branches have Second Lieutenant, First Lieutenant, Captain, Major, Lieutenant Colonel, Colonel, Brigadier General, Major General, Lieutenant General, General, and General of the Army/Air Force.

Navy and Coast Guard

For the enlisted, Navy and Coast Guard ranks include Seaman Recruit, Seaman, Petty Officer Third Class, Petty Officer Second Class, Petty Officer First Class, Chief Petty Officer, Senior Chief Petty Officer, and Master Chief Petty Officer.

The officer ranks in the Navy and Coast Guard include Ensign, Lieutenant Junior Grade, Lieutenant, Lieutenant Commander, Commander, Captain, Rear Admiral (Lower Half), Rear Admiral (Upper Half), Vice Admiral, Admiral, and Fleet Admiral.

It's also worth noting that within each rank, there are jobs or "ratings" which have their own names and abbreviations, and promotions aren't solely based on time in service, but also on job performance and the needs of the branch.

To your question about equivalency, there is somewhat equivalence across branches. For example, an Army Corporal would generally equate to a Navy or Coast Guard's Petty Officer Third Class, though the duties and roles might be quite different. Similarly, an Air Force Major is roughly equivalent in rank to a Navy Lieutenant Commander.

In determining which path might be best for you, consider not just rank structure but also where and how you would like to serve, the culture of each branch, and what kind of work you hope to do. Each service branch has unique opportunities, specific benefits, different tour lengths, and varying requirements. It's important to consider all these aspects as you make an informed decision.