Inflation Calculator
Compare a future equivalent price with the purchasing power of an unchanged cash amount under your chosen inflation rate.
Future equivalent price
User-entered constant rate; no live CPI data or price forecast. Real spending baskets have different price changes. Negative rates represent deflation and can produce a purchasing-power gain rather than a loss.
Formula checked · NumberSwift · Review process
For informational purposes only. Results are estimates and do not constitute financial advice.
How this calculator works
Compound the entered annual price change over the selected number of years. Multiplying the starting amount by that factor gives the future nominal price of the same basket under the assumption. Dividing an unchanged nominal amount by the factor expresses its later buying power in today’s units. These are inverse comparisons: a higher future equivalent price and a lower purchasing-power equivalent describe different sides of the same assumption.
Formula
Price factor = (1 + inflation/100)^years. Future equivalent price = amount × factor. Present purchasing-power equivalent = unchanged amount ÷ factor. Loss percentage = (1 − 1/factor) × 100.
Assumptions & limitations
User-entered constant rate; no live CPI data or price forecast. Real spending baskets have different price changes. Negative rates represent deflation and can produce a purchasing-power gain rather than a loss.
Worked example
At 3% for 10 years, a 1,000 basket has a future equivalent price of about 1,343.92. An unchanged 1,000 cash amount then buys about 744.09 in today’s units, a purchasing-power loss of about 25.59%.
Our approach to calculations ↗Common questions
Does this use the latest official inflation rate?
No. You supply the annual rate. The tool intentionally uses no external data or inflation API.
Why is purchasing-power loss not equal to the price increase?
The comparisons use reciprocal factors and different denominators. A 25% price rise reduces unchanged cash buying power by 20%.
Can I model deflation?
Yes, within the supported negative rate range. Future equivalent price falls and the loss output becomes a gain.