Inflation explained: why your money buys less over time

Inflation is a sustained rise in the general price level. When prices rise, each dollar buys less. A salary that stays flat during inflation is a pay cut in real terms, even though the number on the payslip has not changed.

How it is measured

Statistical agencies track the prices of a basket of goods and services. The consumer price index, or CPI, is the most familiar measure in the United States. It includes food, housing, transport, medical care and other categories, weighted by typical spending.

No single index describes every household. Your personal inflation depends on what you buy. A renter with childcare costs may experience a very different rate from a homeowner without children. Use the index as a guide, not a precise personal number.

Real versus nominal

Nominal values are the numbers on the statement. Real values are adjusted for inflation.

If a savings account pays 4% while prices rise 3%, the real return is about 1%. If the account pays 2% in the same environment, the real return is negative. The balance grows, but its purchasing power falls.

The approximation is: real return ≈ nominal return − inflation. For larger rates, use the exact formula: (1 + nominal) / (1 + inflation) − 1.

Who is helped and hurt

Borrowers with fixed-rate debt can benefit. The dollars used to repay the loan are worth less, and the interest rate does not rise with inflation.

Savers in low-rate accounts are hurt because their money loses purchasing power.

Workers are affected by whether wages keep pace. Long periods of falling real wages are a common source of household stress.

People on fixed incomes feel inflation quickly because their payments may adjust slowly or not at all.

What to do about it

• Keep cash for emergencies, but do not hold every dollar in cash. Inflation erodes idle balances.
• Compare real returns, not just headline rates. A 5% return with 4% inflation is weaker than it looks.
• Consider inflation-protected savings where available, such as inflation-indexed government bonds.
• Do not assume high inflation lasts forever. Forecasts are uncertain, and long-term plans should survive a range of outcomes.
• Review long-term goals. A retirement number calculated in today's dollars needs to account for future prices.

Inflation and compound interest

Inflation compounds too. Over 20 years, 3% annual inflation turns $100 of purchasing power into about $55. That is why long-horizon projections should use real returns.

Our compound interest calculator can model nominal growth. To translate a future balance into today's money, discount it by expected inflation. For more on the mechanics, read how compound interest works.

Inflation is not a single event or a moral judgment. It is a measure of changing prices, and it belongs in every long-term financial comparison.