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Inflation Calculator

See how a fixed annual inflation rate erodes your money's future cost and buying power.

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How to use

  1. 1.Enter the amount of money you have today in dollars.
  2. 2.Enter the annual inflation rate you want to assume (use a negative number for deflation) and the number of years.
  3. 3.Read the future cost and future purchasing power, which update instantly as you change any input.

About Inflation Calculator

The Inflation Calculator projects how a constant annual inflation rate changes the value of money over time. Type in an amount you have today, the annual inflation rate you want to assume, and a number of years — the tool instantly shows two figures: the future cost of that basket of goods and the future purchasing power of that same amount of money.

These are two sides of the same coin. Future cost answers "what will something that costs $100 today cost in 10 years?" — at 3% annual inflation, the answer is about $134.39. Future purchasing power answers the reverse: "what will $100 actually buy in 10 years, measured in today's money?" — about $74.41. As prices rise, each dollar buys less, so a fixed sum of cash quietly loses buying power even while its face value never changes.

The math is a straightforward compound-inflation model. Future cost multiplies the amount by (1 + r) raised to the number of years, where r is the annual rate written as a decimal. Future purchasing power divides the amount by the same factor. Because the two operations are inverses, they let you look at inflation from whichever direction fits your question — planning a future expense, or checking how much your savings will really be worth.

Important: this is a rate-based projection, not historical data. It assumes one fixed inflation rate for the entire period. Real inflation, measured by indexes like the Consumer Price Index (CPI), rises and falls every year, so the actual outcome will differ. Use the tool to build intuition and compare scenarios — for example, how 2%, 4%, and 6% each play out over 20 or 30 years — rather than to predict an exact price.

The calculator also handles deflation. Enter a negative rate (say -2%) and future cost falls below the starting amount while purchasing power rises, reflecting periods when prices decline. Everything runs entirely in your browser: no data leaves your device, there is nothing to sign up for, and results update as you type. It is a quick way to stress-test retirement savings, long-term goals, salary expectations, or any figure you want to keep meaningful over time. Because inflation touches financial planning, treat the output as general information only and confirm any decisions with a licensed professional.

Methodology & sources

Uses the standard compound-inflation formula. Future cost = amount x (1 + r)^n and future purchasing power = amount / (1 + r)^n, where r is the annual inflation rate as a decimal (annualRatePct / 100) and n is the number of years. The model assumes a single constant annual rate for the entire period and does not use real historical CPI data, so actual inflation — which varies year to year — will differ. Negative rates are allowed to model deflation; amount and years must be zero or positive. Estimates are for general information only and are not financial advice; verify figures with a licensed professional.

Frequently asked questions

Does this calculator use real historical inflation data?
No. It is a rate-based projection that applies one constant annual inflation rate across the whole period. Real inflation, tracked by indexes such as the Consumer Price Index (CPI), changes every year, so actual results will differ. Use this to compare scenarios, not to predict exact prices.
What is the difference between future cost and future purchasing power?
Future cost is what something priced at your amount today will cost in the future: amount x (1 + rate)^years. Future purchasing power is what your amount of cash will actually buy in the future, measured in today's money: amount / (1 + rate)^years. They are inverses of each other.
Can I model deflation with a negative rate?
Yes. Enter a negative annual rate (for example -2%) to model deflation. Future cost then falls below your starting amount and purchasing power rises above it, because prices are declining. The amount and number of years must still be zero or positive.

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