Educational tool. Not financial advice. Uses a flat inflation assumption; actual CPI varies across countries, decades, and consumption baskets.
Inflation Calculator — Purchasing Power & CPI Impact Online
Enter an amount and inflation rate to see how purchasing power declines over time. The chart shows erosion with the original value for comparison.
How to adjust for inflation
- Enter a historical amount and the year it refers to.
- Specify the inflation rate series (CPI, PCE, or a custom annual rate).
- The calculator returns the equivalent purchasing power in a target year.
- Use the output to compare today's prices against historical ones in real terms.
Common use cases
- Assessing whether a price increase on a product over years is in line with inflation or a real cost increase.
- Modelling required income at retirement to maintain today's standard of living accounting for future inflation.
- Comparing a salary offer against the same role's historical pay in real terms.
- Understanding how inflation erodes the real return of nominal-yield fixed-income investments.
Frequently asked questions
Which inflation index should I use?
For general purchasing power, CPI is the standard. For specific spending patterns, consider PCE (less weight on housing) or a custom rate based on your own spending categories.
Does inflation affect all goods equally?
No. Housing, healthcare and education typically outpace overall CPI; technology deflates. For personal planning, weight categories by your actual spending.
Is a real return the same as inflation-adjusted?
Yes. Real return = nominal return minus inflation. A 5% nominal return in a 3% inflation year is a 2% real return — closer to what actually grew your purchasing power.
Is my data stored?
No. Calculations run in your browser.
About inflation
Inflation reduces what your money can buy. At 3% annual inflation, $100 today buys only $55 worth of goods in 20 years. Investing above inflation is essential to preserve wealth.
- Purchasing power erosion chart
- Dollar amount and percentage lost
- Adjustable inflation rate (0.5-15%)
- Up to 50 years horizon
- Export chart as PNG
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Sources (2)
- Fisher, I. (1930). The Theory of Interest, as Determined by Impatience to Spend Income and Opportunity to Invest It. Macmillan, New York (Fisher equation: real ≈ nominal − inflation).
- U.S. Bureau of Labor Statistics (2024). Consumer Price Index (CPI-U) — Methodology. BLS Handbook of Methods, Chapter 17.
These are the original publications and regulations the formulas in this calculator are based on. Locate them by author and year on Google Scholar, SSRN, or the U.S. Government Publishing Office.