Inflation Calculator
Understand how inflation erodes purchasing power over time using US CPI data from 1990–2025.
Inflation is the quiet force that makes a dollar buy a little less every year, and over decades the effect is dramatic: the $100 your grandparents spent is not remotely the $100 you spend today. This calculator uses historical US Consumer Price Index (CPI) data to show how the purchasing power of a given amount has changed between any two years, so you can compare prices, salaries, and savings across time on a level playing field.
It answers questions that come up constantly in finance and everyday life: Is a salary that sounded great in 2000 actually competitive now? How much would a 1990 price be in today's money? Is my savings account keeping up with the cost of living, or quietly losing value? By translating old dollars into today's terms (and vice versa), the tool makes historical comparisons honest and intuitive.
Plug in some numbers —
we'll crunch.
How to use
- 1Enter the dollar amount you want to compare.
- 2Select the starting year.
- 3Select the ending year.
- 4See how much the same purchasing power costs today.
How it works
The calculation rests on the Consumer Price Index, a basket of goods and services whose total cost is tracked over time. To convert an amount from one year to another, you scale it by the ratio of the two years' index values: Adjusted = Amount × (CPI in target year ÷ CPI in original year). If prices doubled between the two years, the ratio is 2 and your old amount needs twice as many of today's dollars to buy the same things.
The average annual inflation rate between two years is the geometric growth rate implied by that ratio. Historically, US inflation has averaged roughly 2–3% per year, but it has spiked far higher in some periods (the late 1970s, the early 2020s) and gone near zero in others. Because the effect compounds, even a modest 3% annual rate roughly halves purchasing power over about 24 years.
Worked examples
What an old salary is worth today
You earned $40,000 in 2000 and want to know the equivalent in 2025 dollars.
- Find the CPI ratio between 2025 and 2000 (prices roughly doubled over that span).
- Adjusted ≈ 40,000 × 1.85 ≈ $74,000.
A $40,000 salary in 2000 had about the same purchasing power as roughly $74,000 today. If your pay has not risen by a similar multiple, your real income has fallen.
Is cash losing value?
You keep $10,000 in an account earning 1% while inflation runs 4%.
- Nominal balance after a year: 10,000 × 1.01 = $10,100.
- But you need 10,000 × 1.04 = $10,400 just to match last year's buying power.
Despite the balance "growing" to $10,100, you have lost about $300 of real purchasing power. This is why cash sitting idle during high inflation quietly shrinks.
Tips & common mistakes
Remember that CPI is an average across a broad basket of goods — your personal inflation rate can differ a lot depending on where you live and what you buy. Housing, healthcare, and education have often risen faster than the headline figure, while electronics have fallen, so the official number may understate or overstate your own experience.
Use inflation adjustments when comparing anything across years: salaries, house prices, ticket costs, or investment returns. A common mistake is celebrating a "record high" nominal number that is actually lower in real terms once inflation is stripped out. Real (inflation-adjusted) figures tell the truth; nominal ones can mislead.
For your own money, the lesson is that beating inflation — not just earning a positive return — is the real goal. A savings rate below the inflation rate means you are losing ground in real terms every year. This tool reflects past US CPI data for general education; it is not a forecast, and future inflation may look nothing like the historical average.
Frequently asked questions
⚠ Based on historical US Consumer Price Index data for educational purposes only. It is not a forecast of future inflation and not financial advice.
Last reviewed: June 2026
About this calculator
Understand how inflation erodes purchasing power over time using US CPI data from 1990–2025.