Enter the maximum heart rate, resting heart rate, age, and weight into the calculator to determine the Fitness Index. This calculator can also evaluate any of the variables given the others are known.

Fitness Index Formula

The following formula is used to calculate the Fitness Index.

FI = (HRmax - HRrest) / (Age - Weight)


  • FI is the Fitness Index
  • HRmax is the maximum heart rate (beats per minute)
  • HRrest is the resting heart rate (beats per minute)
  • Age is the individual’s age (years)
  • Weight is the individual’s weight (kilograms)

To calculate the Fitness Index, subtract the resting heart rate from the maximum heart rate. Then, subtract the individual’s weight from their age. Divide the first result by the second result to get the Fitness Index.

What is a Fitness Index?

A Fitness Index is a numerical value that represents an individual’s overall physical health and fitness level. It is typically calculated based on various factors such as age, gender, body mass index (BMI), cardiovascular endurance, muscular strength, flexibility, and other health-related parameters. The higher the fitness index, the better the individual’s physical fitness and health. This index can be used to track fitness progress over time, identify areas for improvement, and establish fitness goals.

How to Calculate Fitness Index?

The following steps outline how to calculate the Fitness Index.

  1. First, determine the maximum heart rate (HRmax) in beats per minute.
  2. Next, determine the resting heart rate (HRrest) in beats per minute.
  3. Next, determine the individual’s age (Age) in years.
  4. Next, determine the individual’s weight (Weight) in kilograms.
  5. Next, gather the formula from above = FI = (HRmax – HRrest) / (Age – Weight).
  6. Finally, calculate the Fitness Index.
  7. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

HRmax: maximum heart rate (beats per minute) = 180

HRrest: resting heart rate (beats per minute) = 70

Age: individual’s age (years) = 30

Weight: individual’s weight (kilograms) = 70