Buying Power Calculator

Find out how much of your money's buying power inflation erodes over time. Enter an amount, an annual inflation rate, an optional annual growth rate for the amount, and a time horizon to see the future buying power in today's dollars and how much value is gained or lost.

Quick Facts

Formula
Real value = Amount x ((1 + g) / (1 + i))^n
g is the amount's annual growth rate, i is annual inflation, and n is the number of years.
No growth case
Real value = Amount / (1 + i)^n
With growth rate set to 0%, this is the standard purchasing-power erosion formula.

Your Results

Calculated
Future buying power (today's $)
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Real, inflation-adjusted value
Future nominal amount
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Amount after the growth rate, unadjusted
Change in buying power
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Real dollars gained or lost
Change in buying power (%)
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Real percentage change from today

Ready

Enter an amount, inflation rate, growth rate, and time horizon, then press Calculate.

How the Buying Power Calculator works

Buying power (purchasing power) is what a given amount of money can actually buy — and it shrinks every year that prices rise faster than the money itself grows. This calculator applies the Fisher relationship between nominal and real value to show how much of today's buying power a sum retains after a chosen number of years of inflation, optionally offset by a steady growth rate (a raise, a cost-of-living adjustment, or an investment return).

The formula

For a current amount A, an annual growth rate g (how fast the amount itself increases, if at all), an annual inflation rate i, and a horizon of n years, the future buying power expressed in today's dollars is:

Real value = A × ((1 + g) / (1 + i))n

If the amount does not grow (g = 0%), the formula reduces to the standard purchasing-power erosion calculation, Real value = A / (1 + i)n — the familiar "inflation shrinks your savings" math. The future nominal amount, before adjusting for inflation, is simply A × (1 + g)n.

Worked example

Take $10,000 today with 3.5% annual inflation and no growth (g = 0%) over 10 years. The future buying power is $10,000 / (1.035)10 ≈ $7,089 in today's dollars — a loss of about $2,911, or 29.1% of its original purchasing power, even though the nominal $10,000 figure never changes.

Now suppose a $60,000 salary grows 3% per year while inflation runs at 3.5%. After 10 years the nominal salary is about $80,635, but its real buying power is only about $57,163 in today's dollars — roughly a 4.7% real decline, because the 3% raise did not quite keep pace with 3.5% inflation.

What moves the result most

  • The gap between growth and inflation: what matters for buying power is not the inflation rate alone but the difference between how fast your money grows and how fast prices rise. A 5% raise against 3% inflation grows real buying power; a 2% raise against 3% inflation still loses ground.
  • Time horizon: erosion compounds. The same 3.5% inflation rate costs a small share of buying power after one year but roughly 30% after a decade and over 50% after 20 years.
  • The inflation rate itself: because it compounds exponentially, doubling the inflation rate more than doubles the buying-power loss over a multi-year horizon.

What this calculator does not model

This is a pure real-versus-nominal value calculation. It assumes a constant annual inflation rate and a constant annual growth rate for the full horizon, and it does not account for taxes on investment gains, changes to the inflation rate itself, or the risk that a return does not materialize. Use it to understand the mechanics of purchasing-power erosion, not as a guarantee of what any specific investment or salary will do.

Frequently Asked Questions

How is buying power calculated?
The calculator applies the Fisher relationship to find real, inflation-adjusted value: Future buying power = Current amount x ((1 + growth rate) / (1 + inflation rate))^years. If the amount does not grow (growth rate = 0%), this reduces to the standard purchasing-power erosion formula: Future buying power = Current amount / (1 + inflation rate)^years.
What if my income or savings grow over time?
Enter an annual growth rate to model a raise, cost-of-living adjustment, or investment return that offsets inflation. When the growth rate exceeds the inflation rate, buying power increases in real terms; when it lags inflation, buying power still erodes even though the nominal dollar amount keeps rising.
What inflation rate should I use?
There is no single correct answer; use your own estimate. In the United States, the Bureau of Labor Statistics publishes the Consumer Price Index each month as the standard reference for realized inflation, and many planners use a long-run historical average as a forward-looking assumption for calculators like this one.
Does this account for taxes or investment risk?
No. This is a pure inflation-adjustment calculator: it models how rising prices erode purchasing power and, optionally, how a steady growth rate offsets that erosion. It does not model investment risk, taxes on returns, wage volatility, or changes in the inflation rate during the period.

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