Your money is not disappearing. It is just quietly being repriced.
Use this free inflation calculator to see what something costing a given amount today will cost in the future. Enter an amount, an annual inflation rate, and a number of years to get the future cost — the same basket of goods, a larger price tag.
Inflation is the reason a salary that felt generous in 2015 feels tight now, and the reason cash under a mattress loses a quiet third of its value per decade. The math is identical to compound interest, running in the direction you do not want.
What This Inflation Calculator Does
- Calculates the future cost of today's amount at a given inflation rate
- Shows how quickly modest rates compound over 10, 20, or 30 years
- Useful for retirement planning, salary negotiation, and long-term budgets
- Flip the interpretation to see lost purchasing power (see the notes)
How to Use the Inflation Calculator
Inputs:
- Amount — today's cost or amount in dollars
- Inflation Rate — annual rate in % (default 3, near the long-run US average of ~3.2%)
- Years — how far ahead to project
Steps:
- Enter today's amount
- Set an inflation rate — 2% is the Fed target, 3% the historical average, 4–5% for a pessimistic case
- Enter the number of years and click Calculate
- To see purchasing power instead, divide today's amount by the growth factor: $1,000 ÷ 1.806 = $554 in 20 years at 3%
How the Calculation Works
Future Cost = Amount × (1 + Rate ÷ 100)^Years
Purchasing Power = Amount ÷ (1 + Rate ÷ 100)^Years
- Same compounding formula as interest — inflation is simply compound growth applied to prices
- At 3%, prices double in about 24 years (Rule of 72: 72 ÷ 3). At 2%, 36 years. At 7%, just 10
- Real return = nominal return − inflation. A 6% investment during 3% inflation grows your purchasing power by ~3%
- Official US inflation is measured by the CPI, a weighted basket; your personal rate depends on whether your spending is rent, tuition, and healthcare (higher) or electronics (often lower)
Worked Example: $60,000 of annual spending, 3% for 25 years
- Growth factor = 1.03^25 = 2.094
- Future cost = 60,000 × 2.094 = $125,640 per year
- Same lifestyle, more than double the dollars — which is what "plan for inflation in retirement" actually means
- Reverse view: $60,000 stuffed in a safe today buys $28,650 worth of 2026 goods in 2051. The safe was the risky choice.
Tips (From People Who Have Made These Mistakes)
- When negotiating a raise, a "3% increase" during 3% inflation is a 0% raise. Say that out loud in the meeting
- Compare long-term investment returns in real terms. The S&P 500's ~10% historical nominal return is ~7% after inflation
- Fixed-rate debt is the one thing inflation helps: you repay a fixed amount with cheaper dollars
- Retirement projections need an inflation assumption. A plan built on today's prices understates the target by half over 25 years
Frequently Asked Questions
How do you calculate inflation?
Future cost = amount × (1 + rate)^years. $100 at 3% for 10 years becomes $134.39. Reported inflation rates come from the year-over-year change in the Consumer Price Index.
What will $100,000 be worth in 20 years?
In purchasing power at 3% inflation: $100,000 ÷ 1.03^20 = $55,368. Held as cash, it loses nearly half its value — the argument for investing rather than hoarding.
What is a normal inflation rate?
The US long-run average is about 3.2%, and the Federal Reserve targets 2%. Recent years spiked above 8% before falling back, which is why long projections use a range, not a point.
How long until prices double?
Roughly 72 ÷ inflation rate years. At 3% about 24 years; at 6% about 12. The Rule of 72 works in both directions.
Does this calculator show future prices or lost value?
It shows the future cost of today's amount. For lost purchasing power, divide instead of multiply by the same growth factor — both views are in the notes above.
Mini Roast Disclaimer
We roast the number, not you. The economy is doing this to everyone simultaneously, which is the only comforting thing about it.
Reality Check
Projections assume a constant rate, and real inflation swings year to year — near zero in 2015, above 8% in 2022. Your personal rate depends on your spending mix, since rent, healthcare, and education have risen far faster than the average. Use a range (2% optimistic, 3% baseline, 4% cautious) rather than betting a 30-year plan on one number.