Inflation Calculator
Enter a dollar amount and a number of years to see how inflation erodes purchasing power. Works both ways: what today's money will be worth later, or what a past amount would be worth today.
Result
Breakdown
Year-by-Year
How inflation math works
Inflation compounds. If prices rise 3% per year, then after n years the same basket of goods costs (1.03)n times as much. To find future value at inflation rate r: FV = PV · (1+r)n. To find what a past dollar is worth today: Now = Then · (1+r)n. To find the present-day purchasing power of a future dollar: divide instead of multiply.
Historical US inflation averages
Long-run US CPI inflation has averaged roughly 2.5–3.5% per year over the last century, with wide variation: 13%+ during the 1979–1981 spike, near 0% during 2009, and 6%+ in 2021–2022. The Federal Reserve targets 2% inflation as monetary policy. For long-horizon planning, 2.5–3% is a reasonable default assumption.
Why 3% matters more than it sounds
At 3% inflation, a dollar loses roughly half its purchasing power every 24 years. That means $100k of retirement savings at age 40 is worth ~$50k in today's purchasing power by age 64 even if the nominal balance doesn't change. Inflation is why cash-under-the-mattress is a losing strategy over long horizons.