The $100,000 is the "present value" and the $120,000 is the "future value" of your money. In this case, if the interest rate used in the calculation is 20%, there is no difference between the two. To calculate that simply plug the inflation rate and the starting amount into this "How much would it cost calculator" (see below). Using our Inflation Calculator, you can calculate the amount of price inflation between any two dates from 1914 to the present. Or you can use the current inflation rate (see ticker above). If additional money is added into an economy, each unit of money in circulation will be worth less. The inflation rate itself is generally conveyed as a percentage increase in prices over 12 months. Most developed nations try to sustain an inflation rate between 2-3% through fiscal and monetary policy.