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Inflation calculator

Enter an amount, an annual inflation rate and a period in years. The calculator works out what that amount will be worth in today's money after that period, and the cumulative inflation over the whole period.

Result

Purchasing power after the period

Cumulative inflation over the period

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This calculation is for informational purposes only and does not replace advice from a qualified professional. Formulas and rates may not fit your exact situation — double-check the figures before making decisions.

How it is calculated

Purchasing power after the period = amount today ÷ (1 + annual inflation) ^ number of years. This isn't "how much money is left" — the nominal amount doesn't change — it's how many of today's goods and services that same nominal amount will buy after the given period.

Cumulative inflation over the period = ((1 + annual inflation) ^ number of years − 1) × 100% — that's not the annual rate times the number of years: inflation compounds the same way deposit returns do, so 5% a year over 10 years isn't 50%, it's noticeably more.

This calculation mirrors compound interest: there, a sum grows over time; here, its purchasing power shrinks. When comparing an investment's return against inflation, it's the real return (net of inflation) that matters, not the nominal one — otherwise an investment can look like it's growing while actually losing purchasing power.

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