Body fat for male, 38in waist
Estimated body fat percentage for a male with a 38in waist, 15in neck, and 70in height.
Different measurements? Use the full body fat calculator for your exact numbers.
About this body fat calculator
This calculator uses the U.S. Navy circumference method, developed in the 1980s as a fast, equipment-free way to estimate body fat percentage using just a tape measure. Instead of calipers or expensive scanning equipment, it relies on measurements of your neck, waist, and — for women — hips, combined with your height, to estimate body fat through a logarithmic formula.
For men, the formula uses the difference between waist and neck circumference. For women, it uses waist plus hip circumference minus neck circumference. Larger differences generally correspond to a higher estimated body fat percentage, while the height term adjusts for the fact that taller and shorter people carry circumference differently relative to their frame.
The Navy method isn't as precise as DEXA scans, hydrostatic weighing, or skinfold calipers used by trained professionals, but multiple studies have found it reasonably accurate for the general population — typically within a few percentage points — which makes it a convenient way to track trends over time using nothing but a tape measure.
Measurement technique matters: measure your neck just below the larynx, your waist at the navel (or the narrowest point for women), and your hips at the widest point, keeping the tape snug but not compressing the skin. Measuring at the same time of day and in the same way each time will give you the most consistent trend data.
Body fat percentage is one piece of the health picture, not the whole picture. This calculator provides a general estimate for educational purposes and is not a diagnostic tool. Consult a healthcare provider or a professional with proper equipment for a more precise assessment or personalized guidance.
Body fat calculator questions
How the U.S. Navy circumference method works.
How does this body fat calculator work?
It uses the U.S. Navy circumference method, which estimates body fat percentage from your height and the circumference of your neck and waist (plus hips for women), using a validated logarithmic formula.
How accurate is the U.S. Navy method?
It's generally within a few percentage points of more precise methods like DEXA scans for most people, making it a convenient way to estimate and track body fat trends without special equipment.
Where do I measure my neck, waist, and hips?
Measure your neck just below the larynx (Adam's apple), your waist at the navel (or the narrowest point for women), and — if you're female — your hips at their widest point. Keep the tape snug but not compressing the skin.
Why does the formula differ for men and women?
Men and women tend to store fat differently, so the Navy method uses waist minus neck circumference for men, and waist plus hip minus neck circumference for women, to better reflect those differences.
What do the body fat categories mean?
Categories range from essential fat (the minimum needed for basic health) through athletic, fitness, average, and obese ranges. The healthy ranges differ between men and women because women naturally carry more essential body fat.
Is this as accurate as a DEXA scan or calipers?
No — DEXA scans and skinfold calipers performed by trained professionals are generally more precise. The Navy method is a convenient at-home estimate that's reasonably accurate for tracking general trends.
How often should I remeasure?
Body fat changes gradually, so remeasuring every 2–4 weeks, at the same time of day and using the same technique, gives a more meaningful trend than daily measurements.
Is this medical advice?
No. This calculator provides a general estimate for educational purposes only and isn't a diagnostic tool. Talk to a healthcare provider for a precise assessment or personalized guidance.