Inflation Calculator
Enter an amount, years and your assumed annual inflation rate to compare future equivalent cost and purchasing power. No live CPI data is used.
Calculator arithmetic runs locally in your browser and does not require an API.
The interactive calculator loads here when JavaScript is enabled.
How to use Inflation Calculator
Choose a scenario rate yourself. A negative rate represents deflation; this is not a lookup of historical prices.
Formula and method
Future cost = amount × (1 + r)^years. Purchasing power of the unchanged nominal amount = amount / (1 + r)^years.
Understanding the results
Future cost is what the current purchase could cost under the assumption. Reverse purchasing power expresses the same nominal amount in today’s terms; it is not a price forecast.
Worked example
At an assumed 3% for 10 years, a 1,000 purchase has future equivalent cost 1,343.92. An unchanged 1,000 then has purchasing power of about 744.09 in today’s terms.
These are mathematical estimates, not financial advice or an offer of credit.
Frequently asked questions
Where does the inflation rate come from?
You enter it. The calculator does not fetch CPI or official inflation statistics.
Why are cost and purchasing power different?
Cost multiplies by the inflation factor; purchasing power divides by it. They answer opposite questions.
Can I model falling prices?
Yes. A negative annual assumption models constant deflation within the supported input range.