About This Calculator
Money that just sits still loses purchasing power every year inflation runs above zero — this calculator shows exactly how much. Give it an amount, a number of years, and an assumed annual inflation rate, and it shows two related numbers: what today's amount will actually be able to buy in the future (its eroded, real value), and how much money you'd need at that future date just to match what today's amount can buy right now. It also shows how sensitive the result is to the inflation rate you assume, and a year-by-year breakdown of the erosion. Everything is calculated locally in your browser.
Two Ways to Think About It
Future purchasing powerAmount ÷ (1 + rate)^years — if you set today's amount aside and it doesn't grow, this is what it will actually be able to buy after inflation, expressed in today's terms.
Equivalent future amountAmount × (1 + rate)^years — the inverse question: how many future dollars would you need at that later date to have the same buying power as today's amount has right now.
Why both matterThe first shows what happens if you don't grow your money at all (cash sitting idle). The second is useful for setting a future savings or income target that keeps pace with inflation.
This isn't the same as investment growthThis tool only models inflation eroding a static amount — it doesn't include any return you might earn by investing that money, which is a separate calculation (see the compound interest and investment tools on this site).
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