Inflation Calculator
See what a sum of money is worth after inflation, how much purchasing power is lost over time, or how much you need to maintain your living standard. Uses compound inflation for accurate results.
Purchasing power over time
Reference inflation rates
| Scenario | Rate |
|---|---|
| US Fed target | 2.0% |
| US historical avg (1913–2024) | ~3.3% |
| US 2022 peak | 9.1% |
| UK historical avg | ~3.5% |
| Eurozone target (ECB) | 2.0% |
| High-inflation scenario | 6–8% |
What Is Inflation and How Does It Erode Purchasing Power?
Inflation is the sustained increase in the general price level of goods and services in an economy over time. When prices rise, each unit of currency buys fewer goods and services than it did before — this reduction in buying power is what economists call the erosion of purchasing power. Inflation is not something that happens to money in a bank account; it happens to everything money can buy.
At 3% annual inflation — close to the US long-term historical average — prices roughly double every 24 years. This means $100,000 in savings today has the purchasing power of $50,000 in 24 years if your money earns exactly 3% (keeping pace). If your savings earn less than inflation, your real wealth is shrinking automatically, every year, even as the nominal dollar balance may be growing.
This calculator quantifies exactly what inflation costs over any time period, what a future amount is worth in today's dollars, and how much you need to invest to maintain your purchasing power.
The Purchasing Power Formulas
There are two core calculations, depending on what you need to know:
Future cost = Present amount × (1 + inflation rate)^years
Present value = Future amount ÷ (1 + inflation rate)^years
Example 1 — future cost: A college education that costs $50,000 today will cost $50,000 × (1.04)^18 = $101,276 in 18 years at 4% annual tuition inflation. You would need to double your savings target to maintain the same purchasing power.
Example 2 — today's value of a future amount: You expect to receive a $500,000 inheritance in 20 years. In today's dollars at 3% inflation, that is worth $500,000 ÷ (1.03)^20 = $277,000 today — nearly half what the number looks like.
US Historical Inflation Rates: Context for Your Calculations
| Decade | Average annual inflation | Notable events |
|---|---|---|
| 1920s | -1.1% (deflation) | Post-WWI deflation, then roaring twenties |
| 1930s | -2.0% (deflation) | Great Depression — prices fell sharply |
| 1940s | 5.6% | WWII and post-war spending surge |
| 1950s | 2.1% | Post-war stabilisation |
| 1960s | 2.4% | Great Society programs begin |
| 1970s | 7.4% | Oil shocks, stagflation crisis |
| 1980s | 5.1% | Volcker rate hikes tame inflation |
| 1990s | 3.0% | Goldilocks economy |
| 2000s | 2.6% | Moderate; financial crisis ends decade |
| 2010s | 1.8% | Post-crisis low inflation environment |
| 2020–2023 | 5.2% | COVID supply shocks, Fed rate hikes |
| Long-term average (1913–2024) | ~3.3% | 111 years of CPI data |
For long-term planning (retirement, college savings, estate planning), using 3%–3.5% as your inflation assumption is well-supported by history. For conservative planning, 4% provides a margin of safety. The Federal Reserve targets 2% — which represents a policy aspiration, not a guarantee.
How Inflation Is Measured: CPI Components
The Consumer Price Index (CPI) is published monthly by the US Bureau of Labor Statistics. It tracks price changes for a representative "basket" of goods and services purchased by urban consumers:
| Category | Weight in CPI | Recent trend |
|---|---|---|
| Shelter (housing, rent) | ~43% | Persistent; lags market rents by ~12 months |
| Food and beverages | ~14% | Volatile; food at home vs away-from-home diverge |
| Transportation | ~15% | Highly volatile; fuel costs dominate |
| Medical care | ~9% | Historically rises 2–3% above general CPI |
| Education | ~3% | College tuition historically 4–6% annual inflation |
| Recreation | ~5% | Technology deflation offsets other rises |
| Apparel | ~3% | Globalization has kept this near zero |
| Other | ~8% | Haircuts, personal care, financial services |
Core CPI excludes food and energy (the most volatile components) to show the underlying inflation trend. The Federal Reserve prefers the PCE (Personal Consumption Expenditures) deflator, which weights goods by actual spending patterns rather than a fixed basket — it typically runs 0.2%–0.4% below CPI.
The Rule of 70: How Fast Do Prices Double?
The Rule of 70 provides a fast mental calculation for how long it takes prices to double at any given inflation rate:
Years to double = 70 ÷ annual inflation rate (%)
| Inflation rate | Rule of 70 (approx.) | Exact doubling time |
|---|---|---|
| 2% (Fed target) | 35 years | 35.0 years |
| 3% | 23.3 years | 23.4 years |
| 3.3% (historical avg.) | 21.2 years | 21.3 years |
| 5% | 14 years | 14.2 years |
| 7% | 10 years | 10.2 years |
| 9% (2022 peak) | 7.8 years | 8.0 years |
| 12% | 5.8 years | 6.1 years |
Protecting Your Savings from Inflation
Cash sitting in a low-yield account loses real value automatically. Here are the main strategies for maintaining and growing purchasing power:
- High-yield savings accounts (HYSAs) — Currently 4.5%–5.5% APY, above inflation. Best for short-term savings and emergency funds. Rate will fall as the Fed cuts rates.
- Treasury Inflation-Protected Securities (TIPS) — US government bonds whose principal adjusts with CPI. The real yield is fixed; your total return keeps pace with inflation by definition. Available through TreasuryDirect.gov or via ETFs (TIP, SCHP).
- I-Bonds (Series I savings bonds) — Inflation-indexed US savings bonds. Rate resets every 6 months based on CPI. No state or local tax on interest. Limited to $10,000/person/year. One-year minimum hold; 3-month interest penalty if redeemed within 5 years.
- Equities (stocks, index funds) — The S&P 500 has returned ~7% annually after inflation over the long term. While volatile short-term, stocks are the primary long-term inflation hedge for most investors. Dividends that grow with earnings provide additional inflation protection.
- Real estate — Property values and rents tend to rise with inflation over time. Direct real estate ownership is illiquid; REITs (Real Estate Investment Trusts) offer liquid exposure with mandatory 90% dividend distribution.
- Commodities (gold, oil, agricultural products) — Often spike during inflationary periods. Gold is a traditional inflation hedge but produces no income and is highly volatile. Suitable as a small portfolio diversifier, not a primary inflation hedge.
Inflation's Impact on Retirement Planning
Inflation is the most underestimated risk in retirement planning. A retiree who does not account for inflation will find their purchasing power shrinking every year throughout retirement:
| Retirement spending need | In 10 years (3% inflation) | In 20 years | In 30 years |
|---|---|---|---|
| $3,000/month | $4,032 | $5,418 | $7,281 |
| $4,000/month | $5,376 | $7,224 | $9,707 |
| $5,000/month | $6,720 | $9,031 | $12,136 |
| $6,000/month | $8,064 | $10,837 | $14,563 |
A retiree spending $5,000/month today will need $12,136/month in 30 years just to maintain the same lifestyle — assuming 3% inflation. This means retirement savings need to generate not just a flat income but a growing income. Portfolio withdrawal strategies (like the 4% rule) assume inflation-adjusted withdrawals, meaning the nominal dollar withdrawal increases each year with CPI.
Real vs Nominal Returns: A Critical Distinction
Every investment return you see quoted is almost always a nominal return — before inflation. The real return is what actually matters for your purchasing power:
Real return = [(1 + nominal return) / (1 + inflation)] – 1
| Nominal return | Inflation | Real return | Interpretation |
|---|---|---|---|
| 10% | 3% | 6.8% | Good — strong real growth |
| 5% | 3% | 1.94% | Modest — barely beating inflation |
| 3% | 3% | 0% | Breaking even — no real growth |
| 1% (traditional savings) | 3% | -1.94% | Losing purchasing power |
| -5% (poor investment year) | 8% | -12% | Significant real wealth destruction |
Unlike income tax, capital gains tax, or VAT, inflation requires no legislation and sends no bill. It simply erodes the purchasing power of everyone holding currency or fixed-income assets — silently, continuously, and disproportionately affecting those with the least ability to protect themselves (retirees on fixed incomes, savers in low-yield accounts, and workers whose wages lag price increases). Central bank inflation targeting at 2% is partly an acknowledgment that moderate, predictable inflation is a policy tool: it discourages hoarding cash and encourages productive investment.
Frequently Asked Questions
What is purchasing power and how does inflation affect it?
Purchasing power is the quantity of goods and services a given amount of money can buy. At 3% annual inflation, $10,000 today buys the same goods as $7,441 in 10 years — your money has lost 25.6% of its purchasing power. Conversely, to buy the same goods in 10 years, you would need $13,439 — a 34.4% increase in nominal dollars needed for the same real basket of goods.
What is the difference between CPI and core inflation?
CPI (Consumer Price Index) measures price changes across all goods and services, including volatile food and energy components. Core CPI excludes food and energy because they fluctuate sharply due to weather, geopolitics, and supply disruptions — masking the underlying inflation trend. The Federal Reserve focuses on core PCE (Personal Consumption Expenditures) inflation, which runs slightly below core CPI. Policymakers track core inflation to see the "signal" separate from the "noise" of commodity price swings.
How does the Federal Reserve control inflation?
The Fed's primary tool is the federal funds rate — the interest rate banks charge each other for overnight lending. When inflation is high, the Fed raises this rate, which flows through to higher mortgage rates, credit card rates, and business loan rates. Higher rates make borrowing more expensive, reducing consumer spending and business investment, which cools demand and eventually reduces price pressure. The process works with a lag of 12–18 months, which is why monetary policy is described as a "blunt instrument."
What are TIPS and how do they protect against inflation?
TIPS (Treasury Inflation-Protected Securities) are US government bonds whose principal value adjusts automatically with CPI. If you own $10,000 of TIPS and CPI rises 4%, your principal becomes $10,400. The fixed interest rate (coupon) is applied to this adjusted principal, so your interest payments also rise with inflation. At maturity, you receive the greater of the original or inflation-adjusted principal. TIPS are the purest inflation hedge available — though they typically offer lower yields than regular Treasuries as compensation for the inflation guarantee.
How does inflation affect mortgage and debt?
Inflation actually benefits fixed-rate borrowers. If you have a $300,000 mortgage at 3.5% fixed rate and inflation runs at 5%, you are repaying a fixed nominal debt with dollars that are worth less in real terms each year. Your real debt burden shrinks with inflation. This is why periods of high inflation historically transferred wealth from savers and lenders (whose fixed payments became worth less) to debtors (who repaid in depreciated dollars). It is also why central banks prioritise inflation control — runaway inflation destroys lending markets and savings incentives.
Is deflation (falling prices) better than inflation?
Deflation sounds appealing but is generally more damaging than moderate inflation. When prices fall, consumers delay purchases ("why buy today if it is cheaper tomorrow?"), businesses cut production and workers, wages fall, debt burdens increase in real terms, and the economy can spiral into recession. Japan's "lost decade" of the 1990s-2000s is the classic example of deflationary stagnation. Most economists consider 2%–3% inflation healthier than zero, because it provides a cushion against deflationary spirals and gives the Fed room to cut rates if needed.