Body Fat Navy Calculator

Body fat navy calculator estimates a percent from height, neck, and waist in centimeters. The opening male values 175, 38, and 85 display as 23.5 percent. It is not a clinical test.

The two formulas

Male percent is 86.01 times the base-10 log of waist minus neck, minus 70.041 times the base-10 log of height, plus 36.76. Female percent is 163.205 times the base-10 log of waist plus hip minus neck, minus 97.684 times the base-10 log of height, minus 78.387. Sex starts on Male, with height 175, neck 38, and waist 85. Hip starts at 95 and appears only for Female. The male result for those opening numbers is about 23.47 before display, and the line shows 23.5 percent. Switching to female with hip 95 gives about 53.77 before display, and the line shows 53.8 percent. The button reads Calculate. The second line says the estimate is informational and not medical advice.

What the tape measure does not prove

The percent is not body fat from a scan or a scale. Units are centimeters, not inches. A waist that is not greater than the neck throws Waist must be greater than neck. A female estimate with no hip throws Hip measurement required for female estimate. A waist plus hip that is not greater than the neck throws Waist + hip must be greater than neck. Zero or a negative height, neck, or waist throws Enter positive measurements. A blank field throws Enter a valid number. The display keeps one decimal place. The raw male value is not printed. There is no age field and no weight field. The hip default of 95 is used only after you switch sex.

How to check 23.5

Leave sex on Male and the three opening numbers, then press Calculate. The first line should be Estimated body fat: 23.5%. Change waist to 38, equal to the neck, and expect the waist error rather than a percent. Switch to Female without changing hip from 95 and expect 53.8 on the first line. If the hip field is hidden, sex is still Male. The labels say cm. Do not type inches in those boxes.

The measurements stay in the tab

The formulas run in this browser. The measurements are not uploaded. The result is an estimate for your notes, not a diagnosis. Nothing is stored when you leave. A second press uses the fields as they stand. The formulas were last checked in October 2026. Male uses waist minus neck. Female uses waist plus hip minus neck, which is why the hip field exists only on that choice. A result above 50 percent on the sample female numbers is the formula output, not a second scale. The display keeps one decimal, so 23.5 and 53.8 are rounded from the longer values. Inches are not accepted in these fields.