Inflation calculator
See how inflation changes the future cost — and buying power — of money.
Runs 100% in your browser- Future cost (same goods)
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- Worth in today’s money
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- Purchasing power lost
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How to calculate inflation
- Enter an amount. Type the sum of money you want to test.
- Set rate and years. Add an annual inflation rate and a number of years.
- Read both views. See the future cost and today’s purchasing power.
Two sides of the same calculation
Inflation compounds exactly like interest, only in reverse — it erodes what money buys rather than growing it. This tool shows both directions of that. The future cost answers "what will something that costs this much today cost in N years?" by growing the amount at the inflation rate: amount × (1 + rate) raised to the years. The purchasing power answers the mirror question — "what will this amount of money be worth in today's terms?" — by discounting it the other way. At 3% inflation, a $50,000 salary needs to become about $67,000 in ten years just to stand still, and $50,000 received then buys only about what $37,000 does now.
The rule that makes it intuitive
Because inflation compounds, its effect over time is larger than people expect. The rule of 70 makes it tangible: divide 70 by the inflation rate to estimate the years for prices to double. At 3.5% that is about 20 years; at 7%, just ten. The same arithmetic explains why a pay rise that merely matches inflation is no raise at all in real terms, and why cash left in a low-rate account quietly loses ground every year it fails to keep up. Small annual percentages become large gaps once you let them run for a decade or two.
Using it in a financial plan
The practical use is converting nominal figures into real ones. A retirement projection that looks generous in future dollars can be sobering once you discount it for inflation, so it is worth checking any long-term goal in today's-money terms. Compare your expected growth in the compound interest calculator against the inflation rate here — only the gap between them is real growth — and factor an inflation assumption into your FIRE number. This tool uses a constant rate you enter, not historical CPI, so set it to whatever long-run assumption you find reasonable.
Educational tool only — not financial advice. Uses a constant rate you enter, not historical CPI.
Frequently asked questions
- It applies a constant annual inflation rate over a number of years. It shows two things: what an amount will cost in the future, and what a future amount is worth in today’s purchasing power.
- Long-run inflation in the US has averaged roughly 2–3%, but it varies. Enter whatever rate you want to model — the result scales directly with it.
- It’s how much your money can actually buy. $100 today buys less in ten years if prices rise — the purchasing-power figure shows that erosion.
- No — it uses the constant rate you enter, not historical CPI tables. That keeps it private and lets you model any scenario.
- No — it computes in your browser.