What is the rank associated with the O-4 pay grade?

The rank associated with the O-4 pay grade is Lieutenant Commander. In the U.S. Navy, the officer ranks are designated by a combination of letters and numbers, where 'O' refers to officer ranks. O-4 signifies the fourth rank in the officer grading system.

Lieutenant Commander holds responsibilities that are greater than those of a Lieutenant but are less than those of a Commander. Generally, the Lieutenant Commander may lead departments, command smaller ships, or serve in various specialized staff positions. This rank reflects a level of experience and responsibility that typically involves leadership and operational roles within the Navy, making it a crucial part of the naval hierarchy.

Other ranks mentioned, such as Commander, Captain, and Rear Admiral (lower half), correspond to higher pay grades (O-5, O-6, and O-7 respectively), which would not accurately represent the O-4 designation. Therefore, Lieutenant Commander is the correct association with the O-4 pay grade.