Contrary to popular belief, there is no maximum "weight" to join or stay in the military. "Weight" is not the standard. Body-Fat percentage is.
However, it takes more time to measure body-fat than it does to weigh a member. Therefore, each of the services have weight charts that they use to "screen" members. If a military member weighs more than the allowed weight on the chart, they are measured for body-fat percentage.
Body-fat standards are used to determine initial qualification for enlistment/accession and also to determine whether or not a member continues to meet required standards after joining. Military members are periodically weighed (and measured, if necessary) throughout their career. Those found to be over their body-fat limits are entered into a mandatory weight loss program. Those who fail to maintain required body-fat standards are subject to administrative sanctions which can include reprimands, denial of promotions, administrative demotion in rank, and even administrative discharge. (Exception: The Air Force no longer uses weight/body fat measurements, except for initial entry. Instead, a "Body Composition" measurement is an integrated componant of the Air Force Physical Fitness Test).
Individuals who exceed the maximum weights shown on the below charts are measured for body-fat percentage:
Army (new recruits)
Army (standards after entry)
Air Force (new recruits only)
Navy (new recruits)
Navy (standards after entry)
Marine Corps (new recruits only)
Marine Corps (standards after entry)
The Department of Defense formula to compute body-fat percentage is somewhat complicated. For males, the formula is % body fat = 86.010 x log10(abdomen - neck) - 70.041 x log10(height) + 36.76, and for females, the formula is % body fat = 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387.
However, you don't have to worry about that, as DOD has prepared charts, based on the above formula (see below), that one can use to look up their body-fat percentage, after taking the proper measurements.
Abdomen. Measure abdominal circumference against the skin at the navel (belly button), level and parallel to the floor. Arms are at the sides. Record the measurement at the end of member's normal, relaxed exhalation. Round abdominal measurement down to the nearest ½ inch.
Neck. Measure the neck circumference at a point just below the larynx (Adam's Apple) and perpendicular to the long axis of the neck. Do not place the tape measure over the Adam's Apple. Service member should look straight ahead during measurement, with shoulders down (not hunched). The tape will be as close to horizontal as anatomically feasible (the tape line in the front of the neck should be at the same height as the tape line in the back of the neck). Care should be taken so as not to involve the shoulder/neck muscles (trapezius) in the measurement. Round neck measurement up to the nearest ½ inch.
Subract the neck measurement from the abdomen measurement, then look up the results on the following charts:
Neck. Measure neck circumference at a point just below the larynx (Adam's Apple) and perpendicular to the long axis of the neck. The Service member should look straight ahead during measurement, with shoulders down (not hunched). Round the neck measurement up to nearest ½ inch.
Waist. Measure the natural waist circumference, against the skin, at the point of minimal abdominal circumference, usually located about halfway between the navel and the lower end of the sternum (breast bone). When you cannot easily see this site, take several measurements at probable sites and use the smallest value. Be sure that the tape is level and parallel to the floor. The Service member's arms must be at the sides. Take measurements at the end of member's normal relaxed exhalation. Round the natural waist measurement down to the nearest ½ inch.
Hip. Measure the hip circumference while facing the Service member's right side by placing the tape around the hips so that it passes over the greatest protrusion of the gluteal muscles (buttocks) as viewed from the side. Make sure the tape is level and parallel to the floor. Apply sufficient tension on the tape to minimize the effect of clothing. Round the hip measurement down to the nearest ½ inch.
Add the waist and hip measurements together, then subract the neck measurements. Look up the results on the following charts: