The Formula for Calculating Inflation

The formula for calculating the Inflation Rate using the Consumer Price Index is relatively simple. Every month the Bureau of Labor Statistics (BLS) surveys prices and generates the current Consumer Price Index (CPI). Let us assume for the sake of simplicity that the index consists of one item and that one item cost $1.00 in 1984. The BLS published the index in 1984 at 100. If today that same item costs $1.85 the index would stand at 185.0

By looking at the above example, common sense would tell us that the index increased (it went from 100 to 185). The question is how much has it increased? To calculate the change we would take the second number (185) and subtract the first number (100). The result would be 85. So we know that since 1984 prices increased (Inflated) by 85 points.

What good does knowing that it moved 85 do? Not much. We still need a method of comparison.

Since we know the increase in the Consumer Price Index we still need to compare it to something, so we compare it to the price it started at (100). We do that by dividing the increase by the first price or 85/100. the result is (.85). This number is still not very useful so we convert it into a percent. To do that we multiply by 100 and add a % symbol.
So the result is an 85% increase in prices since 1984.


How Does Inflation Affect You?

When people go the the grocery store and see ever higher prices they know how inflation affects them. But when they are feeling more philosophical they might reason that if all wages and prices increased at the same rate it would all balance out in the end right?

Well theoretically yes but in reality it never works that way. Prices of various items all increase at different rates so some people are benefiting while others suffer. Those on fixed incomes suffer the most because the cost of things they are buying increases but their income stays the same.