Inflation Calculator
Estimate future buying power after annual inflation.
An inflation calculator estimates how the purchasing power of money changes over time due to rising prices, using a chosen annual inflation rate. This purchasing power calculator can project forward - showing what a given amount will be worth in the future - or work backward to show how much past prices have grown into today's dollars, making it equally useful as a dollar inflation calculator or for any other currency.
Enter an amount, an annual inflation rate, and a number of years to see the equivalent future cost or the eroded purchasing power of that amount.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| $100 today, 3% annual inflation, 20 years | ≈$180.61 | Future cost = $100 × 1.03^20 ≈ $100 × 1.8061 = $180.61 - you would need about $180.61 in 20 years to buy what $100 buys today. |
| $50,000 today, 4% annual inflation, 10 years | ≈$74,012 | Future cost = $50,000 × 1.04^10 ≈ $50,000 × 1.4802 = $74,012. |
How Inflation Erodes Purchasing Power
The U.S. Consumer Price Index (CPI) is the most commonly referenced measure of inflation, tracking the average price change of a broad basket of consumer goods and services over time. Historically, U.S. inflation has averaged around 2-3% annually over long periods, though it has varied significantly in shorter windows, including periods above 5-9% and periods near zero. At just 3% annual inflation, prices roughly double every 24 years, a consequence of the same compounding math used for investment growth, just working in the opposite direction against your money's value.
Why Nominal Returns Are Not the Whole Story
An investment that grows 7% per year while inflation runs at 3% produces a real (inflation-adjusted) return of roughly 4%, not 7% - the difference matters significantly for long-term financial planning, since a retirement or savings goal expressed in today's dollars needs to account for how much prices will rise before you reach that goal.
Using This Calculator for Retirement and Long-Term Planning
Because retirement planning often spans decades, even a modest, realistic inflation assumption compounds into a large effect on how much you'll actually need. A retirement target of $1,000,000 in today's dollars might require a much larger nominal dollar figure 30 years from now just to maintain the same purchasing power - this calculator helps translate between today's dollars and future dollars for that kind of long-range planning.
How to Use the Inflation Calculator
- Open the Inflation Calculator and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the inflation calculator works.
Frequently Asked Questions
How to calculate inflation on a dollar amount?
Multiply the starting amount by (1 + inflation rate) raised to the number of years: future cost = amount * (1 + rate)^years. This calculator runs that formula for you as a dollar inflation calculator for any amount and rate.
How much will $100 be worth in 20 years with inflation?
It depends on the assumed inflation rate - at a 3% average annual rate, $100 today would need to become roughly $180 in 20 years just to maintain the same purchasing power; enter your own assumption into the calculator for a precise figure.
What is a typical inflation rate to use for planning?
Many long-term financial plans use a rate in the 2-3% range, reflecting long-run historical U.S. averages, though actual annual inflation has varied considerably above and below that range in different periods.
What's the difference between nominal and real returns?
Nominal return is the stated percentage growth before adjusting for inflation. Real return subtracts the effect of inflation, showing the actual increase in purchasing power - a 7% nominal return with 3% inflation is roughly a 4% real return.
What is CPI and how does it relate to inflation?
The Consumer Price Index (CPI) is the most commonly cited measure of U.S. inflation, tracking average price changes across a broad basket of consumer goods and services over time.
Why does inflation matter for retirement planning?
Because retirement savings need to cover decades of future expenses, even modest inflation compounds significantly over time - a dollar target set in today's terms will need to be much larger in future nominal dollars to buy the same amount.
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Last updated: September 27, 2026.