このページでは米軍の階級章についてお話させていただきたいと思います。
各軍によって、階級と名称が異なるものがあったりして、混乱しそうですね。「Captain」は、海軍では大佐ですが、それ以外では大尉です。

階級章の画像の大きさは相対比ではありませんので、ご留意ください。
Pay
Grade
階級陸軍海軍空軍海兵隊
O-10元帥General of the Army
Fleet Admiral
General of the Air Force
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大将General
Admiral
General
General
O-9中将Lieutenant General
Vice Admiral
Lieutenant General
Lieutenant General
O-8少将Major General
Rear Admiral (Upper Half)
Major General
Major General
O-7准将Brigadier General
Rear Admiral Lower Half
Brigadier General
Brigadier General
O-6大佐Colonel
Captain
Colonel
Colonel
O-5中佐Lieutenant Colonel
Commander
Lieutenant Colonel
Lieutenant Colonel
O-4少佐Major
Lieutenant Commander
Major
Major
O-3大尉Captain
Lieutenant
Captain
Captain
O-2中尉First Lieutenant
Lieutenant Junior Grade
First Lieutenant
First Lieutenant
O-1少尉Second Lieutenant
Ensign
Second Lieutenant
Second Lieutenant
WO-5准尉長Chief Warrant Officer Five
Chief Warrant Officer Five
Chief Warrant Officer Five

N/A
Chief Warrant Officer Five
WO-4准尉長Chief Warrant Officer Four
Chief Warrant Officer Four
Chief Warrant Officer Four
Chief Warrant Officer Four
WO-3准尉長Chief Warrant Officer Three
Chief Warrant Officer Three
Chief Warrant Officer Three
Chief Warrant Officer Three
WO-2准尉長Chief Warrant Officer Two
Chief Warrant Officer Two
Chief Warrant Officer Two
Chief Warrant Officer Two
WO-1准尉Warrant Officer One
Warrant Officer One
Warrant Officer One
Warrant Officer One
E-9上級曹長Sergeant Major of the Army
Master Chief Petty Officer of the Navy
Chief Master Sergeant of the Air Force
Sergeant Major of the Marine Corps
E-9上級曹長Command Sergeant Major
Fleet/Force Master Chief Petty Officer
Command Chief Master Sergeant
Sergeant Major
E-9上級曹長Sergeant Major
Command Master Chief Petty Officer
Chief Master Sergeant
Master Gunnery Sergeant
E-8曹長First Sergeant
Master Chief Petty Officer
Senior Master Sergeant
First Sergeant
E-8曹長Master Sergeant
Senior Chief Petty Officer
Master Sergeant
E-7一等軍曹Sergeant First Class
Chief Petty Officer
Master Sergeant
Gunnery Sergeant
E-6二等軍曹Staff Sergeant
Petty Officer First Class
Technical Sergeant
Staff Sergeant
E-5三等軍曹Sergeant
Petty Officer Second Class
Staff Sergeant
Sergeant
E-4伍長Corporal

Specialist
Petty Officer Third Class
Senior Airman
Corporal
E-3上等兵Private First Class
Seaman
Airman First Class
Lance Corporal
E-2一等兵Private, E-2
Seaman Apprentice
Airman
Private First Class
E-1兵卒Private, E-1

N/A
Seaman Recruit

N/A
Airman Basic

N/A
Private

N/A