Inflation Calculator

How inflation erodes the value of money

Inflation is the steady rise in prices, so the same dollar buys a little less each year. Compounded over decades the effect is dramatic: at 3% a year, prices roughly double in about 24 years and the purchasing power of a fixed sum is cut in half. This calculator shows both sides of that — the growing number of dollars you would need to buy the same goods later, and the shrinking real value of the money you hold today.

The math is compound, not linear. To get a future cost you multiply by (1 + inflation) once for each year; to get today’s buying power you divide. That is why cash left idle loses value even though the number in the account never drops, and why long-term goals — retirement above all — have to be planned in inflation-adjusted terms rather than today’s prices. A number that looks comfortable now can fall far short in thirty years.

To keep up with or beat inflation, money generally has to earn a return above the inflation rate; the gap between the two is your real return. Long-run US inflation has averaged roughly 3%, but it swings year to year, so treat the rate you enter as an assumption and test a few scenarios. This tool models a single constant average rate and does not use official CPI history — it is a planning estimate, not a historical price lookup.