Body mass index (BMI) and body fat percentage (BFP) are important calculations used in the fitness world to determine the healthiness of individuals.

What is the body mass index?

Body mass index is derived by dividing the mass (weight) of an individual, by the square of the person’s height.

BMI = mass / height^2

Sometimes conversion factor is used when the si units (kg and meters), are not used in the calculation.

Generally, a body mass index above 30 is considered obese, a body mass index between 24- 29, is considered overweight, whereas a body mass index between 21-24, is considered normal.

Examples of Body mass index

  • Less than 15 is considered very severely underweight.
  • 15-16 is severely underweight.
  • 16 – 18.5 underweight.
  • Normal weight (healthy weight) ranges from 18.5 – 25.
  • Overweight ranges from 25 – 30.
  • 30 – 35 is considered moderately obese also known as Class I obesity.
  • 35 – 40 is severely obese, also known as class II obesity.
  • 40 – 45 is considered very severely obese (Class III obesity).
  • Bmi of 45 – 50 is considered morbidly obese, it is also known as class IV obesity.
  • 50 – 60 is super obesity (Class V obesity)
  • and finally, a BMI above 60 is considered hyper obesity. People in this category might not even be able to walk.

What is body fat percentage?

Body fat percentage calculates the number of fats contained in an individual’s body.

It is calculated by dividing the total amount of fats present in an individual, divided by the total mass of that individual, multiplied by 100.

BFP = mass of fats / total body mass * 100

Body fat percentage is a little bit skewed since it sometimes fails to account for athletes who are generally heavier due to their muscles. As such, a different range of values is used for men and women.

Body Fat Percentage (BFP) women

  • 10-14% is essential fat in females.
  • 14-21% are female athletes.
  • 21-25% is considered as fit females.
  • 25-32% is considered overweight (average) females.
  • Female body fat percentage above 32% is considered obese

Body Fat Percentage (BFP) men

  • 3-5% is essential fat in males.
  • 6-14% are male athletes
  • 14-18% are fit males.
  • 18-25% is considered overweight (average) females.
  • Male body fat percentage above 25% is considered obese.

Difference between BMI and BFP

  1. Body mass index has no unit, whereas body fat percentage, as the name implies is given in percentage.

Similarities between BMI and BFP

  1. They both calculate the healthiness of an individual.