This body fat calculator measures the fat percentage and the lean body weight but also the BMI and BMR values to maintain a healthy body. You can read below the form about the body fat values and what these can indicate.

Age: *
Weight: *
Height: *
Neck: *
Waist: *
Activity level: *

How does the body fat calculator work?

This weight tool can estimate the level of fat in the body, the lean body weight as well as offer values for the two important indicators: BMI (body mass index) and BMR (basal metabolic rate).  

All you have to do is enter the data required then the body fat calculator will do the work and return you an estimate for your body status. You need to input the age and gender then some basic measurements, whether you like to use English or metric, you are asked for height, weight and neck and waist dimensions. This form uses the U.S Navy Method to estimate the fat percentage. Its formula is:

Body fat men=495/(1.0324-0.19077(Log(waist-neck))+0.15456(Log(height)))-450    

Body fat women=495/(1.29579-0.35004(Log(waist+hip-neck))+0.22100(Log(height)))-450

Example calculation:

Let’s take for instance the case of a 34 year old female, weighing 165 lbs at a height of 5ft 4in, with a waist of 35 in and neck dimension of 13 in. We also need to add the hip measurement that is in this case 47 in and the level of activity which is sedentary. The result is:

■ Your Body Fat is 44.7%;
■ Body Fat: 33.46 kg;
■ Lean Body Weight is: 41.39 kg;
■ Your Weight is: Overweight;
■ Your BMI is: 27.5;
■ Your BMR is: 1,510.9 calories/day;
■ Minimum Calorie requirement is: 1,813 daily calories/day.

What is the body fat percentage?

This is a measure of fitness level or an indicator of the body shape and it can be obtained by dividing the estimated amount of body fat to the total body mass.

The range of the body fat percentage released by The American Council on Exercise:

Description Women Men
Essential fat 12-15% 2-5%
Athletes 16-20% 6-13%
Fitness 21-24% 14-17%
Acceptable 25-31% 18-25%
Obese 32%+ 25%+

Measurement techniques for body fat

  • Using BMI
  • Using height and circumference
  • Underwater weighing
  • Body average density
  • Skinfold
  • Ultrasound


1) Jackson AS, Stanforth PR, Gagnon J, Rankinen T, Leon AS, Rao DC, Skinner JS, Bouchard C, Wilmore JH. (2002) The effect of sex, age and race on estimating percentage body fat from body mass index: The Heritage Family Study. Int J Obes Relat Metab Disord;26(6):789-96.

2) Siri WE. (1961) Body composition from fluid spaces and density: Analysis of methods. In Brozek J, Henzchel A. Techniques for Measuring Body Composition. Washington: National Academy of Sciences. pp. 224–244.

24 Dec, 2014