How to measure your waist and height for the military standards

Waist-to-height ratio is your waist measurement divided by your height, in the same units. At 70 inches tall with a 35-inch waist, the ratio is 0.50. The calculation is simple, but small measuring errors move it a lot: at 70 inches, each half inch of waist changes the ratio by about 0.007. That is why it's worth measuring carefully at home before an official measurement.

What you need

• A non-stretch tape. Fiberglass or cloth body tapes are best. Old sewing tapes stretch over time, and a metal tape won't sit flat against the body.
• A wall, a flat floor and a hardback book or carpenter's square for height.
• A mirror, or better, a second person.

Measuring height

1. Take off your shoes and stand on a hard floor with your heels, buttocks and shoulders against a wall.
2. Look straight ahead with your chin level, not tipped up.
3. Slide a book or square down the wall until it rests firmly on the top of your head, and mark the wall under it.
4. Measure from the floor to the mark. Do it twice; the two readings should match within a quarter inch.

Height drops slightly over the day, so measure at the time of day your official measurement usually happens.

Measuring the waist

1. Stand relaxed with your feet together, arms at your sides and stomach not pulled in.
2. Wrap the tape around your waist at the level your branch names. For the Navy and Marine Corps, that is at the navel. For the Army and Air Force, follow the measuring instructions your unit uses.
3. Keep the tape level all the way around. A tape that dips in the back is the most common reason a home reading comes out low. A mirror or a second person catches it.
4. The tape should be snug against the skin without pressing in.
5. Read it at the end of a normal breath out, not after a deep breath in or a forced exhale.
6. Take it two or three times and use the lowest reading that you got with a level tape. The Marine Corps measures twice officially and uses the lower value.

How each branch rounds

Rounding the waist down helps you in every branch. Rounding the height up, as the Navy does, also helps. Rounding the height down, as the Marine Corps does, works slightly against you.

Worked example: same body, four results

Take a service member who measures 68.3 inches tall with a 36.8-inch waist.

The same person passes the Army and Navy screens comfortably, loses a few Air Force points, and is over the Marine Corps limit. The Marine standard is the strictest of the four, and its height rounding pushes the ratio up a little further.

Common mistakes

• Measuring over clothing. Even a thin shirt adds to the reading.
• Pulling the tape tight. It feels like a better number, but it won't match the official reading.
• Measuring right after a big meal or a lot of water. Both can raise the reading for a few hours.
• Measuring at the narrowest point instead of the navel when your branch measures at the navel. For many people the narrowest point is an inch or two higher.
• Measuring height in shoes or with your chin up.

Check your numbers

The waist-to-height calculator applies each branch's rounding at once. Branch-specific tools: Army, Navy, Marine Corps, and the body composition component in the Air Force calculator.