Compound Interest and Inflation
Compound interest grows your money — but inflation shrinks its purchasing power. Understanding how they interact is essential for real wealth building.
What is Inflation?
Inflation is the rate at which prices rise over time. At 3% annual inflation, something that costs $100 today will cost $103 next year, $106.09 the year after, and so on — because inflation compounds too.
The Real Rate of Return
Your real return is what you actually gain after inflation:
Real rate ≈ Nominal rate - Inflation rate
If your savings account earns 5% APY and inflation is 3%, your real return is approximately 2%.
The Precise Formula (Fisher Equation)
(1 + real rate) = (1 + nominal rate) ÷ (1 + inflation rate)
Inflation's Impact Over 30 Years
$10,000 nominal vs real value at 3% inflation:
- 10 years: Worth $7,441 in today's dollars
- 20 years: Worth $5,537 in today's dollars
- 30 years: Worth $4,120 in today's dollars
How to Beat Inflation
- Invest in assets that historically outpace inflation (equities, real estate).
- Avoid holding large cash balances long-term.
- Use inflation-protected securities like TIPS for fixed-income portions.
Use our compound interest calculator to model nominal vs real returns side by side.