What is Inflation Calculator?
Formula
Buying Power: Future Value = Past Value ร (CPI_end / CPI_start) Future Cost: Future Value = Present Value ร (1 + inflation_rate)^years Purchasing Power Lost = 1 - (1 / (1 + total_inflation_rate))
Formula Explained
The CPI-based calculation uses the ratio of the Consumer Price Index between two years to determine how much prices changed. The compound growth formula projects future values using an assumed constant inflation rate โ each year, prices increase by the rate percentage applied to the previous year's value. The purchasing power calculation shows how much less a fixed amount of money can buy compared to the reference year.
Example
$100 in 1990 dollars โ 2025 dollars: Average annual inflation ~2.8% over 35 years $100 ร (1.028)^35 = $263.30 So $100 in 1990 has the same buying power as ~$263 today. Conversely, $100 today has the buying power of only ~$38 in 1990 dollars. Total inflation: 163%, Purchasing power lost: 62%
Tips & Best Practices
- โWhen evaluating salary increases, subtract the inflation rate to see your real (inflation-adjusted) raise.
- โFor retirement planning, assume 2.5-3% average inflation when projecting future expenses.
- โInvestments should target returns above inflation to grow real wealth โ stocks have historically returned 7-10% vs 3% inflation.
- โFixed-income investments like bonds and CDs may lose purchasing power if their yield is below inflation.
- โConsider Treasury Inflation-Protected Securities (TIPS) for inflation-hedged savings.
Common Use Cases
- โขComparing historical prices to today (e.g., what $50,000 salary in 2000 equals now)
- โขProjecting future costs of college tuition, healthcare, or housing
- โขEvaluating whether investment returns are beating inflation
- โขSalary negotiation โ understanding if a raise keeps pace with inflation
- โขRetirement planning โ estimating how much future expenses will be