Choose rate of change between points, a balance-weighted percentage rate, or the equal-weighted mean of two rates, then select Calculate. Slope is (y₂ − y₁)/(x₂ − x₁), with different x values required. A weighted rate is Σ(balance × rate)/Σ(balance), using comparable rate periods and compounding conventions. Enter up to eight balance/rate pairs, one per line separated by | or a tab; every pair must be complete. The examples below use Mean of two rates.

Find the change in y for each unit of x between two points.

Related Calculators

Two-Point Average (Arithmetic Mean) Formula

The following two example problems outline the steps and information needed to calculate the two-point average (the arithmetic mean) of an initial and final rate.

AVR = (IR + FR) / 2
  • Where AVR is the two-point Average Rate (simple arithmetic mean)
  • IR is the initial rate 
  • FR is the final rate 

To calculate the two-point average rate, sum the initial and final rates, then divide by 2 (this is an equal-weighted average of the two values).

How to Calculate a Two-Point Average Rate?

The following example problems outline how to calculate the two-point Average Rate (arithmetic mean).

Example Problem #1:

  1. First, determine the initial rate.
    • The initial rate is given as: 50.
  2. Next, determine the final rate.
    • The final rate is provided as: 90.
  3. Finally, calculate the Average Rate using the equation above: 

AVR = (IR + FR) / 2

The values provided above are inserted into the equation below and computed.

AVR = (50 + 90) / 2 = 70

Example Problem #2: 

For this problem, the variables required are provided below:

initial rate = 40

final rate = 30

Test your knowledge using the equation and check your answer with the calculator.

AVR = (IR + FR) / 2 = (40 + 30) / 2 = 35