What you need

  • A flexible, non-stretch measuring tape
  • A mirror or second person to check that the tape stays level
  • A simple record of the landmark, date, and measurement

Do not use a metal construction tape. It cannot wrap smoothly around the body and can create inconsistent tension.

Set up the same conditions

Measure at a similar time of day, ideally before a large meal and not immediately after a workout. Stand relaxed, keep weight distributed evenly, and breathe normally. Do not flex or pull the abdomen inward.

Measuring the waist

  1. Choose the landmark required by the calculator protocol.
  2. Wrap the tape horizontally around the torso.
  3. Keep the tape against the skin without compressing it.
  4. Take the reading after a normal exhale.

Do not silently change landmarks

The narrowest waist, navel, and top of the hip bone can produce different numbers. Record which location you use.

Measuring the neck

Stand upright and look forward. Place the tape at the method’s specified neck landmark, keep it level, and avoid pulling tightly into the skin. Remove bulky clothing and jewelry.

Measuring the hips

Stand with feet together and wrap the tape around the widest part of the buttocks. Use a mirror to confirm that it remains horizontal. The female Navy-style equation uses this measurement.

Repeat and record

Take two measurements. If they differ noticeably, take a third and review tape placement. Record the result to a sensible precision; hundredths of an inch suggest certainty the method does not have.

Use the same process in the body-fat calculator or waist-to-height calculator.

Common errors

  • Measuring over thick clothing
  • Letting the tape slope
  • Compressing the skin
  • Holding the breath
  • Using a different landmark each time
  • Comparing a morning measurement with one after a large meal

Frequently asked questions

Should the tape be tight?

It should be snug and in contact with the skin without creating an indentation.

Can I measure over clothing?

Thin clothing may still add error. Measuring directly against skin is more repeatable.

Why do two waist measurements differ?

Tape position, angle, tension, breathing, food, and posture can all change the reading.

Should I average several measurements?

Repeat to check consistency. If measurements differ, correct the technique before relying on an average.

Sources

References and further reading

Last reviewed: July 10, 2026