Inflation Impact Calculator
See how inflation erodes the purchasing power of money over time. Enter an amount, inflation rate, and years to get the real value of your money in today's dollars and a chart showing purchasing power declining year by year.
How to use this tool
- Enter amount today, annual inflation rate and years in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your future purchasing power (today's $) and the full breakdown beneath it.
Inflation is the silent tax. Even at 3%, the purchasing power of $10,000 falls to about $5,500 over 20 years. Understanding this erosion explains why investing — not just saving — is essential for long-term wealth.
Formula: Real Value = Amount ÷ (1 + rate)years
⚠ This tool provides general estimates for education only and is not financial, tax or legal advice. Figures may not reflect your situation — verify with a qualified professional.
Formula
Real purchasing power after n years: PP = Amount / (1 + r)n
Where r = annual inflation rate as a decimal. Purchasing power lost (%) = (1 − PP / Amount) × 100. Dollars lost = Amount − PP.
How it works
This calculator discounts a present dollar amount by compound annual inflation to show how much of today's purchasing power remains at a future date. It applies the standard present-value discounting formula, computing the result for every year from 0 to the chosen horizon to populate the chart.
The model uses a single fixed inflation rate; actual inflation fluctuates year to year. The result represents the equivalent in today's dollars — if inflation averages 3% per year, $5,000 today will buy only as much in 10 years as roughly $3,720 does today.
Worked example
- Inputs: $5,000 today, 0% annual inflation rate, 10 years.
- Purchasing power = $5,000 / (1 + 0)10 = $5,000 / 1 = $5,000.
- Percent lost = (1 − $5,000 / $5,000) × 100 = 0%.
- Dollars lost = $5,000 − $5,000 = $0.
Future purchasing power: $5,000 | Purchasing power lost: 0% | Dollars lost to inflation: $0
Common mistakes to avoid
- Using a single historical average CPI (~3%) for all scenarios — inflation rates vary widely by category (healthcare vs. electronics), so one rate can misrepresent specific costs.
- Interpreting the purchasing power value as the amount of money you will have rather than the real spending power equivalent of a fixed sum in today's dollars.
- Failing to apply inflation when evaluating a fixed pension or annuity — the chart makes clear that a $2,000/month payment 20 years out is worth far less in real terms.
Key terms
- Purchasing power
- The quantity of goods and services that a unit of currency can buy; inflation reduces purchasing power over time.
- Inflation rate
- The annual percentage increase in the general price level; money held without a matching return loses this percentage of real value each year.
- Compound discounting
- The process of dividing by (1 + r)n to express a future nominal amount in today's equivalent dollars, reversing the effect of compound growth.
- Real value
- The value of money or an asset expressed in terms of purchasing power, after adjusting for inflation; distinct from its nominal (face) value.
- CPI (Consumer Price Index)
- A commonly used measure of inflation that tracks the average price change of a basket of consumer goods and services over time.
Frequently asked questions
- What inflation rate should I use?
- US CPI has averaged roughly 3% over the past century, and around 2.5% since the 1990s. For conservative planning use 3-4%; for optimistic scenarios, 2%.
- How do I protect against inflation?
- Invest in assets that historically outpace inflation: equities, real estate, TIPS (Treasury Inflation-Protected Securities), and I-bonds.