Inflation Calculator

What Is Inflation?

Inflation is a general rise in the prices of goods and services over time, which means each unit of currency buys a little less than it did before. It is usually quoted as a percentage per year: at 3% inflation, a basket of goods that costs $100 today will cost about $103 a year from now — and a $100 bill kept in a drawer will only buy what $97 buys today. Most central banks in developed economies treat roughly 2% as a healthy target: high enough to keep people spending and borrowing rather than hoarding cash, low enough that prices feel stable. Much of the twentieth century averaged close to 3% in the United States, which is why 3% is the default in the scenario calculators above.

How the CPI Measures It

The Bureau of Labor Statistics tracks the price of a large, fixed basket of goods and services — food, housing, transport, medical care, apparel and hundreds more — sampled across U.S. cities every month. The weighted average price of that basket is the Consumer Price Index. The index is anchored so that the average price level of 1982–1984 equals 100, which is why the numbers look large today: a CPI of 336.94 in September 2026 means the basket costs about 3.37 times its 1982–84 price. Inflation between any two dates is simply the percentage change in the index — for example, the CPI rose from 236.916 in January 2016 to 242.839 in January 2017, an increase of 2.5%.

When Inflation Runs Away — and When Prices Fall

At the extreme, hyperinflation is inflation spinning out of control, typically when a government prints money far faster than the economy produces goods: prices can double in days, savings are wiped out, and people flee into foreign currency or hard assets. Germany in 1923 and Zimbabwe in the 2000s are the standard examples. The mirror image is deflation — falling prices, which sound pleasant but discourage spending (why buy today what is cheaper tomorrow?), raise the real burden of debts, and can lock an economy into a downward spiral, as in the early 1930s. The U.S. data above contains both: double-digit inflation in 1917–1920, 1947 and 1979–1981, and outright deflation in 1921, 1930–1933 and 2009.

Why It Happens

Economists group the causes into three families. Demand-pull inflation occurs when spending outruns the economy's capacity to produce, so buyers bid prices up. Cost-push inflation starts on the supply side — an oil shock, a poor harvest or a currency slide raises producers' costs, which get passed on. Built-in inflation is the echo of the other two: workers demand raises to catch up with prices, firms raise prices to cover wages, and expectations alone keep the wheel turning. Underneath all of it sits the money supply: sustained inflation is rarely possible unless the amount of money in circulation grows persistently faster than output.

Protecting Your Money

Cash is inflation's easiest victim: at 2.5% inflation, $50,000 sitting in a non-interest-bearing account loses $1,250 of real value in a single year. The standard defenses are assets whose returns can outpace prices — diversified equities, real estate, commodities such as gold, and inflation-indexed bonds like U.S. Treasury TIPS, whose principal is adjusted with the CPI itself. None is a perfect shield year by year, and diversification matters more than any single hedge; but over long horizons, simply keeping money idle is the one strategy guaranteed to lose ground. The calculators on this page let you measure exactly how much ground, historically or in your own scenario.

Frequently Asked Questions

How does the CPI calculator convert amounts?

Amount at the target date = your amount × CPI(target) ÷ CPI(source). It is a pure price-level ratio, the same method the BLS describes for its own inflation calculator.

Why is October 2025 missing?

The BLS never published it — collection stopped during the 2025 federal government shutdown and the month was never reconstructed. The 2025 annual average here is the mean of the eleven published months, matching the BLS's own reported 2025 average (+2.63% over 2024).

CPI calculator vs. flat-rate calculators — which should I use?

Use the CPI calculator for the past: it is real, measured history. Use the flat-rate calculators for the future or for hypothetical histories, where no CPI exists yet and you must assume a rate.

What is a 1913 dollar worth today?

About $34.03 in September 2026 terms — the CPI has risen roughly 34-fold since the 1913 average. A modern dollar, conversely, buys about what 3 cents bought in 1913.