Free Body Fat Percentage Calculator for Men & Women

Body fat percentage is the proportion of total body weight made up of fat tissue. The rest is lean mass — muscle, bone, water, and organs. Expressed as a single percentage, it gives a snapshot of body composition rather than overall size.

Fat falls into two broad categories. Essential fat is the small amount required for normal physiological function, such as hormone production and organ protection. Storage fat is the additional fat held in adipose tissue, both under the skin and around internal organs.

Because BMI cannot distinguish fat from muscle, body fat percentage is often considered more informative when assessing body composition. Two people with the same BMI can have very different proportions of fat and lean mass.

The US Navy method uses circumference measurements at the waist, neck, and hips (for women) along with height. It was developed and validated for military fitness assessment and tends to track clinical methods within a few percentage points for adults of average build.

The BMI method estimates body fat from height, weight, age, and sex using the Deurenberg equation. It is less accurate because it does not account for fat distribution or muscle mass, but it requires only the inputs you would use for a BMI calculation.

Neither method replaces clinical assessment methods such as DEXA scans, hydrostatic weighing, or air displacement plethysmography, which directly measure body composition under controlled conditions.