Inflation Calculator (purchasing power over time)
Enter an amount, time horizon, and expected inflation rate. The calculator returns both directions: how much you'll need in the future to maintain today's purchasing power, and the present value of a future amount.
- Future cost of today's amount
- 163,862
- What you'll need in N years to buy today's basket of goods.
- Today's value of future amount
- 61,027
- What that amount in N years is worth in today's money.
- Purchasing power lost
- 38,973
- % lost
- 39%
How it works
Why inflation matters for long-term planning
Inflation reduces the purchasing power of money over time. At 2% inflation, $1,000 today buys what $610 buys in 25 years โ almost half. At 5% inflation the erosion is dramatic: same $1,000 buys what $295 buys after 25 years. Even 'low' inflation compounds invisibly over decades.
This is why holding cash long-term is a guaranteed loss in real terms unless interest rates exceed inflation. Savings accounts paying 0.5% lose 1.5% per year against 2% inflation. Investments need to outpace inflation just to break even.
Realistic inflation rates by era and country
Long-term US average (since 1913): about 3.2%. Recent decades have been lower (2010s averaged 1.7%) but 2021-2024 spiked to 4-9% in many countries. Most central banks target 2% as 'price stability'.
Japan: famously low (~0% average for 1990-2020) but recently picked up to 2-3%. Eurozone: 1-3% historically, but 6-10% in 2022. UK: similar to Eurozone. Emerging markets (Turkey, Argentina): often double-digit, sometimes hyperinflation.
For long-horizon planning (10+ years), assume 2-3% nominal in stable economies as a baseline. Stress-test with 4-5% to see how a higher-inflation scenario affects you.
Two formulas, two directions
Future cost: FV = PV ร (1 + i)^n. To maintain $50,000/year living costs at 2% inflation for 30 years, you'll need $90,568/year then. This is the budget-planning view: how much income or balance you need at a future date.
Present value: PV = FV / (1 + i)^n. Receiving $1M in 25 years at 2.5% inflation is worth about $539,000 today. This is the comparison view: when comparing future cash flows (lottery payouts, pension lump sums, retirement accounts), discount to present value to compare apples to apples.
Compound interest grows money exponentially; inflation shrinks it exponentially. For investments to truly grow, you need a real rate (nominal โ inflation) > 0.
Frequently asked questions
โบWhat inflation rate should I use?
For US/EU/JP planning: 2-3% nominal. For stress testing: 4-5%. For currently-volatile periods, the central bank's recent CPI report is most relevant.
โบWhat's CPI?
Consumer Price Index โ a basket of goods/services that governments track to measure inflation. 'Inflation rate' is usually the year-over-year change in CPI.
โบDoes the calculator account for personal inflation rate?
No โ it uses a single rate. Personal inflation varies by spending habits: rent and food inflate differently from electronics. For granular planning, weight by your actual budget.
โบCan inflation be negative (deflation)?
Yes โ enter a negative rate. Japan experienced this in the 2000s. Deflation increases purchasing power over time but is generally bad for the economy (people delay spending).
โบHow is this different from compound interest?
Compound interest grows your money; inflation shrinks its purchasing power. They use the same exponential math but in opposite directions. For real returns, subtract inflation from your nominal investment rate.
โบShould I use this for retirement planning?
Yes โ combine with our retirement-calculator to see both nominal and real (today-dollar) projections of your savings.
โบWhere do I find historical inflation data?
US: BLS.gov. Japan: e-Stat (Statistics Bureau). EU: Eurostat. UK: ONS. World Bank also publishes per-country data going back decades.
โบDoes the data leave my browser?
No. Calculation runs locally; nothing is sent to a server.
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