Inflation & Purchasing Power Calculator

Inflation: The Tax Nobody Votes On

Inflation is the gradual erosion of money's purchasing power over time. At 3% annual inflation, prices double every 24 years. At 7% inflation (as seen in 2022), prices double every 10 years. For long-term financial planning—retirement, savings goals, investment returns—ignoring inflation leads to dramatically incorrect conclusions.

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📉 The Purchasing Power Reality Check

How much is $1,000,000 worth in 20 years at different inflation rates?

| Inflation Rate | $1,000,000 Today → Future Value | Real Purchasing Power in 20 Years | |---|---|---| | 2% (Fed target) | Nominal $1M | Buys $672,000 worth today | | 3% (historical average) | Nominal $1M | Buys $554,000 worth today | | 5% (elevated) | Nominal $1M | Buys $377,000 worth today | | 7% (high inflation) | Nominal $1M | Buys $258,000 worth today |

A retiree with $1,000,000 who doesn't invest—just holds cash—sees their purchasing power cut nearly in half over 20 years at 3% inflation.

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🏦 Inflation vs Asset Returns: What Actually Protects You

| Asset Class | Typical Nominal Return | Inflation-Adjusted (at 3%) | Protection Level | |---|---|---|---| | Cash (under mattress) | 0% | −3% | ❌ None | | Bank savings account | 4–5% (2026) | 1–2% | ⚠️ Minimal | | US Treasury Bonds (10-yr) | ~4.3% | ~1.3% | ⚠️ Modest | | TIPS (Treasury Inflation-Protected) | CPI + 0.5–1% | 0.5–1% real | ✅ Guaranteed | | Real estate | 3–5% + rental yield | 0–2% real | ✅ Good | | S&P 500 (long-term avg) | ~10.5% | ~7.5% real | ✅✅ Strong | | Gold | ~3.5% long-term | ~0.5% real | ⚠️ Modest |

Historical data is clear: broad stock market index funds are the most effective long-term inflation hedge among accessible asset classes.

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📊 The Rule of 72 for Inflation (And Price Doubling)

Just as compound growth doubles money, compound inflation doubles prices: > Years until prices double = 72 ÷ Inflation Rate

| Inflation Rate | Years to Double Prices | |---|---| | 2% (Fed target) | 36 years | | 3% | 24 years | | 4% | 18 years | | 6% | 12 years | | 8% | 9 years |

When planning retirement expenses 30 years away at 3% inflation: multiply today's budget by (1.03)^30 = 2.43. A $50,000/year lifestyle today costs $121,500/year in 30 years—at just 3% inflation.

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🎯 Inflation's Impact on Retirement Planning

Required Portfolio Size Calculation Most retirement calculators ask for "annual spending." But that figure should be in *future dollars*, not today's dollars.

Example: Planning to retire in 25 years, expect to spend what feels like $60,000/year today:

• At 3% inflation: future equivalent = $60,000 × (1.03)^25 = $125,600/year needed
• FIRE Number at 4% withdrawal: $125,600 × 25 = $3,140,000
• If you planned for $60,000 × 25 = $1,500,000, you're underestimating by $1,640,000

Sequence of Returns Risk Inflation in early retirement years is particularly dangerous. High inflation forces you to withdraw more dollars, depleting the portfolio faster—leaving less to recover during low-inflation periods.

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🛡️ Inflation Protection Strategies

TIPS (Treasury Inflation-Protected Securities) US government bonds where the principal automatically adjusts with CPI. Guaranteed real return. Best held in tax-advantaged accounts (the inflation adjustment is taxable annually).

I Bonds (Series I Savings Bonds) US government savings bonds paying CPI + fixed rate. Limit: $10,000/person/year. Rate resets every 6 months based on CPI. Held minimum 1 year; 3-month interest penalty if cashed before 5 years. No default risk.

Real Estate Rents and property values historically track inflation over long periods. Mortgage debt becomes cheaper in real terms during inflationary periods (fixed payment, inflated dollars).

Dividend Growth Stocks Companies that consistently raise dividends (Dividend Aristocrats) provide growing income that tracks or exceeds inflation over decades.