Real vs. Nominal Returns

What Is It

Nominal return is the plain, stated percentage an investment earned — the number on the statement, before anything else is factored in. Real return is that same number adjusted for Inflation, so it reflects growth in actual purchasing power rather than just growth in dollar count. The quick approximation is real return ≈ nominal return − inflation rate; the more precise version divides (1 + nominal) by (1 + inflation) and subtracts 1.

Why It Matters

Every return figure quoted anywhere — a fund's historical average, a savings account's APY, a projection from a Compound Interest calculator — is nominal unless it's explicitly labeled otherwise. That's not a flaw, it's just the default convention, but it means comparing two return figures without checking what inflation assumption sits underneath them can be misleading. A 7% nominal return during a stretch of 6% inflation barely preserved purchasing power; the same 7% during 2% inflation was a real, meaningful gain.

This matters most for long-term projections, where small inflation differences compound over decades right alongside the returns themselves. A retirement plan built entirely on nominal numbers can look more comfortable than it actually is once real purchasing power is the measure that counts.

Quick Example

At a 7% nominal return with 3% inflation, the precise real return is (1.07 ÷ 1.03) − 1 ≈ 3.9% — close to, but not exactly, the quick-and-dirty 7% − 3% = 4% approximation. Over 20 years, $10,000 growing at the full 7% nominal rate reaches about $38,700 in future dollars, but only has the purchasing power of roughly $21,400 in today's dollars once that 3% inflation is factored out.

Try It Yourself

The Compound Interest Calculator's rate field is a nominal rate — run your numbers there, then apply the real-return math above using your own inflation assumption to see what the growth is worth in today's purchasing power.

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