Enter the number of deficits present and the total number of potential deficits into the calculator to determine the Frailty Index. This calculator can also evaluate any of the variables given the others are known.

Frailty Index Formula

The following formula is used to calculate the Frailty Index.

FI = (D / T) * 100

Variables:

  • FI is the Frailty Index (%)
  • D is the number of deficits present
  • T is the total number of potential deficits

To calculate the Frailty Index, divide the number of deficits present by the total number of potential deficits. Multiply the result by 100 to get the Frailty Index as a percentage.

What is a Frailty Index?

A Frailty Index is a tool used in geriatric medicine to quantify the health status of older individuals by measuring their vulnerability to adverse health outcomes. It is calculated by assessing a range of health-related variables, including physical and cognitive impairments, illnesses, and disabilities. The higher the score on the Frailty Index, the more frail the individual is considered to be, indicating a higher risk of mortality, hospitalization, and other negative health events.

How to Calculate Frailty Index?

The following steps outline how to calculate the Frailty Index.


  1. First, determine the number of deficits present (D).
  2. Next, determine the total number of potential deficits (T).
  3. Next, use the formula FI = (D / T) * 100 to calculate the Frailty Index.
  4. Finally, calculate the Frailty Index.
  5. 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.

Number of deficits present (D) = 8

Total number of potential deficits (T) = 10