Inflation Calculator
Estimate how inflation changes the future cost of a basket priced today, and how much purchasing power a fixed cash amount would retain over the same period. These two results are inverse relationships — not the same number.
Your results will appear here
Enter your assumptions and calculate to see the estimated result and supporting details.
How this calculator works
Enter a current amount, an effective annual inflation rate (including zero or deflation above −100%), and a time horizon in years (fractional years allowed).
Primary result is future equivalent cost. Secondary results show purchasing power of unchanged cash and whether purchasing power rose, fell, or stayed the same.
Formula / methodology
futureEquivalentCost = current × (1 + inflation)^years futurePurchasingPower = current / (1 + inflation)^years purchasingPowerChange = futurePurchasingPower − current
- Future equivalent cost answers how much future money buys the same basket.
- Future purchasing power answers what today's unchanged cash is worth later in today's-dollar terms.
- Wording switches among purchasing-power loss, gain, or no change based on the sign of the result.
Worked example
$1,000 today, 3% inflation, 10 years.
Future equivalent cost ≈ $1,343.92. Future purchasing power of $1,000 ≈ $744.09. Purchasing-power loss ≈ $255.91 (about 25.59%).
Important assumptions
- Inflation rate is a constant effective annual assumption you supply — not a live CPI feed.
- Actual inflation varies and is not guaranteed.
- Projection table uses whole years plus a final fractional-year point when applicable.
Common questions
They answer different questions. One scales today's basket into future dollars; the other deflates a fixed cash amount back into today's purchasing power. Mathematically they are inverses.
Negative inflation (above −100%) is allowed. Future equivalent cost falls, purchasing power of fixed cash rises, and the UI reports a purchasing-power gain.