Inflation Calculator
Free online inflation calculator. See how inflation erodes your purchasing power over time. Enter an amount, inflation rate, and time period to calculate future cost, purchasing power loss, and equivalent buying power.
Inflation Calculator
See how inflation erodes your purchasing power over time. Enter an amount, annual inflation rate, and time period to calculate future cost, purchasing power loss, and equivalent buying power with a year-by-year breakdown.
The Formula
Future Cost = Present Value x (1 + r)n
Future Cost — the cost of today's goods or services at a future date
Present Value — today's amount of money being evaluated
r — annual inflation rate (as a decimal, e.g. 3% = 0.03)
n — number of years into the future
To calculate future buying power, invert the formula: Buying Power = Present Value ÷ (1 + r)ⁿ. This shows how much of today's purchasing power remains after inflation compounds over time.
Understanding Inflation
Inflation compounds. Even a modest 3% annual rate doubles prices in about 24 years. Each year's price level builds on the last, so the erosion of purchasing power accelerates over long horizons.
Savings must outpace inflation. A savings account earning 1% while inflation runs at 3% means you are losing 2% of real purchasing power every year — even though your nominal balance is growing.
The Rule of 70. Divide 70 by the inflation rate to estimate how many years it takes for prices to double. At 2% inflation prices double in ~35 years; at 7% they double in ~10 years.
Retirement planning. Always express long-term financial goals in inflation-adjusted dollars. A $1,000,000 retirement target in 30 years at 3% inflation requires roughly $2,427,000 in future dollars to maintain the same real purchasing power.
Price Doubling Reference (Rule of 70)
2% inflation: prices double in approximately 35 years.
3% inflation: prices double in approximately 23 years.
4% inflation: prices double in approximately 17.5 years.
5% inflation: prices double in approximately 14 years.
7% inflation: prices double in approximately 10 years.
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Understanding Inflation
Inflation is the rate at which prices increase over time, reducing the purchasing power of money. If inflation is 3%, something that costs $100 today will cost $103 next year. Your $100 bill stays the same, but it buys less.
The formula for future prices is: Future Value = Present Value × (1 + Inflation Rate)^Years. If inflation averages 3% annually, $100 today will have the purchasing power of only $74 in 10 years. Conversely, you'd need $134 in 10 years to buy what $100 buys today.
Inflation varies by category. Healthcare and education costs have historically risen faster than general inflation. Housing varies by location. Technology costs often decrease. Understanding how inflation affects your specific expenses helps with financial planning.
The Consumer Price Index (CPI)
The Consumer Price Index is the primary measure of inflation in the United States. The Bureau of Labor Statistics calculates CPI by tracking prices of a "basket" of goods and services typical consumers purchase, including food, housing, transportation, healthcare, and entertainment.
CPI-U (Urban consumers) covers about 93% of the US population. CPI-W focuses on urban wage earners and is used for Social Security adjustments. Core CPI excludes volatile food and energy prices to show underlying inflation trends.
Historical CPI data shows significant variation. The US averaged about 3% inflation over the past century, but experienced 13%+ in 1980 and near-zero or negative rates during recessions. When planning, most financial advisors use 2-3% as a reasonable long-term assumption, though actual rates can differ significantly.
Protecting Against Inflation
Inflation erodes savings that don't grow. Money sitting in a checking account earning 0.01% actually loses value when inflation is 3%. Your savings need to grow at least as fast as inflation to maintain purchasing power.
Investments that historically outpace inflation include stocks (average 7% real return), real estate, and Treasury Inflation-Protected Securities (TIPS) which adjust with CPI. High-yield savings accounts and CDs provide some inflation hedge but may not keep pace.
For retirement planning, account for inflation in your projections. If you need $50,000/year in today's dollars and retire in 20 years with 3% inflation, you'll actually need $90,000/year to maintain the same lifestyle. Social Security has inflation adjustments, but other income sources may not. Use this calculator to understand how inflation affects your financial planning.
Purchasing Power Over Time ($100 Today)
| Years | 2% Inflation | 3% Inflation | 4% Inflation |
|---|---|---|---|
| 5 years | $90.57 | $86.26 | $82.19 |
| 10 years | $82.03 | $74.41 | $67.56 |
| 20 years | $67.30 | $55.37 | $45.64 |
| 30 years | $55.21 | $41.20 | $30.83 |
Future Cost of Today's $100 Item
| Years | 2% Inflation | 3% Inflation | 4% Inflation |
|---|---|---|---|
| 5 years | $110 | $116 | $122 |
| 10 years | $122 | $134 | $148 |
| 20 years | $149 | $181 | $219 |
| 30 years | $181 | $243 | $324 |
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