Body Fat Calculator

Body fat percentage from tape measurements, US Navy method.

cm
kg
cm
cm
18%Body fat
FitnessCategory
Fat mass
14.4 kg
Lean body mass
65.6 kg
Waist to height ratio
0.494 Below 0.5 is the usual target

Measure with a soft tape, relaxed and without pulling tight, first thing in the morning for consistency.

Body fat categories for men
CategoryRange
Essential fat2 to 5%
Athletic6 to 13%
Fitness14 to 17%
Average18 to 24%
Above average25% and over

An estimate from tape measurements, not a clinical measurement or medical advice.

About the Body Fat Calculator

Body fat percentage says more about health and fitness than weight alone, because it separates fat from muscle, bone and water. The US Navy circumference method estimates it from a few tape measurements: height and neck for everyone, plus waist for men and waist and hips for women. It needs no equipment and typically lands within three or four percentage points of a DEXA scan, which is enough to track change over time.

Consistency matters more than absolute accuracy. Measure at the same time of day, in the same posture, with the tape snug but not compressing the skin, and compare the trend across weeks rather than individual readings. The waist to height ratio shown alongside is a useful cross-check on its own: keeping your waist under half your height is a simple, evidence-backed health target.

How to use the Body Fat Calculator

  1. Select your sex and enter your height and weight.
  2. Measure your waist at the navel and your neck just below the larynx, and add hips at the widest point for women.
  3. Read the estimated body fat percentage, category, fat mass and lean mass.

Frequently asked questions

How accurate is the Navy body fat formula?

Studies typically find it within three to four percentage points of a DEXA scan for most people. It is less reliable at the extremes and for very muscular builds, but it tracks changes well.

What is a healthy body fat percentage?

Roughly 14 to 24 percent for men and 21 to 31 percent for women is considered normal to fit. Essential fat, below about 5 percent for men and 13 percent for women, is not sustainable or safe long term.

Why do women need a hip measurement?

Women carry a larger share of fat around the hips and thighs, so the formula was fitted with an extra term to capture it. Using the male equation for women would underestimate the result.

What is lean body mass?

Everything that is not fat: muscle, bone, organs and water. Keeping lean mass steady while fat mass falls is the goal of most sensible diet and training plans.