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Inflation calculator

Explore future equivalent costs and unchanged cash purchasing power using your assumed constant inflation rate.

Calculated on your device

Your constant-rate assumption, not current or historical inflation. A negative rate models falling prices.

0–100 years. Fractional years are allowed; no calendar dates are inferred.

Currency sets the money unit. It does not convert exchange rates.

Starting values are an example. Cash is held unchanged, without investment returns or interest.

Try a worked example

Examples use 100 in your selected currency for two years. Undo restores your previous scenario.

Future cost for the same purchasing power
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Purchasing power of unchanged cash in today’s money
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Cumulative modeled price change
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Calculate to see your result.

Assumed-rate scenario, not historical CPI or a forecast. Default inflation is illustrative; currency formats only.

Explore a price-change scenario

  1. Enter the current amount or cost.
  2. Enter an assumed annual inflation rate and years ahead.
  3. Compare the future equivalent cost with the purchasing power of holding the same cash amount unchanged.

Formula and example

Price factor = (1 + inflation ÷ 100)years. Future equivalent cost = current amount × factor. Purchasing power of unchanged cash = current amount ÷ factor, expressed in today’s money. Cumulative price change = (factor − 1) × 100%.

For 100 units, 10% assumed annual inflation and two years, the future equivalent cost is 121, cumulative price change is 21%, and unchanged 100 cash buys about 82.64 units of today’s purchasing power. At a negative assumed rate, prices fall and unchanged cash purchasing power rises.

Investor.gov defines purchasing power in relation to inflation. For actual U.S. historical comparisons, the BLS CPI calculator uses CPI-U data. This tool uses only your constant rate and does not fetch or reproduce a historical price index.

Assumptions and limits

The assumed rate stays constant and compounds annually; fractional years use a fractional exponent. Actual inflation varies by time, place and goods, and your personal expenses may differ from an index. Cash is held unchanged without investment returns, interest, fees or taxes. No exchange-rate conversion, country-specific inflation figures or forecasts are included.

Amount 0.01–1 trillion units; inflation −90% to 100%; horizon 0–100 years, including fractions. These bounds are numeric limits, not suggested rates. Extreme inputs create very large or small outputs; floating-point precision is limited. Very small nonzero amounts and very large amounts use scientific notation to remain readable. Percentages are rounded; scientific notation preserves very small nonzero changes. Estimates are not advice or guarantees.

Privacy and export

Inputs stay in browser memory without uploads or saved financial values. CSV contains the assumptions, both purchasing-power percentages and the price factor as well as the main results. Amounts and percentages normally export to six decimals; nonzero values below 0.000001 and very large numbers use scientific notation. The factor retains numeric precision. Reset restores illustrative defaults. Undo last action restores your inputs, currency search and accepted result after Reset or loading an example. Editing an input discards that recovery step.

Does a 21% price increase mean a 21% purchasing-power loss?

No. Purchasing power divides by the price factor. A 21% increase means unchanged cash retains 1 ÷ 1.21, or about 82.64%, of its previous purchasing power.

Can I compare actual years?

This tool accepts a number of years and a rate, not historical dates or CPI data. Use a suitable official price-index source for a historical comparison.

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