##### How the CPI Calculator Works

The consumer price index calculator allows users to calculate the total change in the consumer price index (hereinafter referred to as CPI) for the desired period.

The calculation of CPI for the selected period is carried out by a chain method based on data on monthly CPI.

For the correct calculation of the CPI, you must specify the initial and final period of time.

**1. Selecting the time period:**

**The initial period (“from”)** corresponds to the period, which is taken as the base one and against which the CPI will be calculated.

**The final period (“before”)** corresponds to the period up to which the CPI will be inclusively calculated (the final period participates in the calculation).

**2. Method of calculation:**

The chain method used in calculating the CPI for the selected period implies the product of all monthly CPI (in coefficients to the previous month), starting from the month following the initial one. So, if it is necessary to calculate the CPI for November 2018 by March 2018, then the monthly CPI will be multiplied using the chain method (in coefficients to the previous month) from April 2018 to November 2018 and the result multiplied by 100%. This is due to the fact that the monthly CPI for April 2018 already contains a change in consumer prices by March 2018.

Result: