Nominal vs Real Return — What's the Difference?

You lock 1,000,000 won into a 4% deposit for a year. A year later, your account shows 1,040,000 won. Did you really get 4% richer? Here's the punchline: that answer completely depends on how much prices moved that year. The same 4% return can leave you richer or poorer. Let's walk through it using two words — nominal and real.

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Nominal return is just what your account shows

Start with nominal return. It's simply the amount you got back divided by the amount you put in. Put in 1,000,000 won, end up with 1,040,000, and your nominal return is 4%. Simple.

Almost every return number in news and ads is nominal. "4% deposit rate," "this fund returned 8% last year" — those are all nominal. It's the number that shows up in your account, so it's the most visible from your side.

The problem is, looking at this number alone tells you nothing about whether you actually got richer. If your account grew but what that money can buy shrank, you didn't really gain wealth.

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Real return measures how much you can actually buy

This is where real return comes in. Real return measures how much more (or less) you can actually buy with your money. Inflation is what creates the gap.

Make it concrete. Last spring, you had 1,000,000 won. At the time, you could buy 100 kg of onions at the grocery store. That's 10,000 won per kg. You deposit that 1,000,000 won, and a year later it's 1,040,000. Nominal return 4%.

But during that year, onion prices rose to 10,500 won per kg. That's 5% inflation. How many kg of onions can your 1,040,000 won buy now? Divide 1,040,000 by 10,500 and you get about 99 kg. A year ago you could buy 100 kg. Now you can buy 99.

Your account grew, but what you can buy shrank. You're effectively about 1% poorer. That's a -1% real return.

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The Fisher equation — a one-line formula

There's a one-line formula that captures this relationship. It's called the Fisher equation, and it's not complicated.

Nominal rate ≈ real rate + inflation rate

Flip it around:

Real rate ≈ nominal rate − inflation rate

Plug in our example: real = 4% − 5% = −1%. A negative number means your money's purchasing power shrank. The exact formula is slightly more involved, but for everyday intuition, subtraction is basically right.

Why does this matter? Because the same nominal return means completely different things depending on the inflation rate.

• Nominal 4%, inflation 2% → real 2% (you got 2% richer)
• Nominal 4%, inflation 4% → real 0% (you broke even)
• Nominal 4%, inflation 6% → real -2% (you got poorer)

The account number rose 4% in all three. Your purchasing power split three different ways.

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How should you actually read your assets?

Here's a common misconception: "isn't a higher deposit rate just better?" Only partly. An 8% nominal rate often shows up in years where inflation runs around 6%. Real rate: 2%. A 2% nominal rate might show up when inflation is closer to 0%. Real rate: 2%. The pace your account grows differs in nominal terms, but the pace you actually get richer ends up about the same.

In a market like Korea's, there are stretches where deposit rates aren't very high while prices climb quickly. People sitting only on deposits end up quietly getting poorer year after year, even without doing anything wrong.

To check your real asset growth, run it like this:

1. A year ago your assets were 100 million won.
2. This year they're 105 million won. Nominal return: 5%.
3. Consumer prices rose 3% during that year.
4. Real return: about 2%. Your purchasing-power-adjusted wealth grew about 2%.

Nominal says 5%, but real says 2%. The headline number looks satisfying, but the actual rate of getting richer is closer to half of it.

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Salary raises run the same logic

This principle applies to investment returns and to your salary the same way.

Your company hands you a 5% raise. From your side, that's a 5% nominal raise. But if consumer prices rise 4% that year, your real raise is about 1%. That's why a 5% raise can still leave your wallet feeling lighter.

In years where prices rise even faster, a nominal 5% raise can turn negative in real terms. You worked harder, but what you can buy shrank. That's why workers bring up "inflation adjustment" during wage negotiations.

Investment returns and salaries alike — looking at the nominal number alone hides how much you actually gained. Always pair it with that year's inflation to see the real change.

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Wrapping up in one line

Nominal is the number in your account. Real is the amount you can actually buy. They're rarely the same. Your true change in wealth only shows up when measured in real terms.

Next time a deposit rate or return ad catches your eye, write that year's inflation right next to it. Subtract one from the other and you get the actual rate at which you got richer that year. A 4% deposit during 4% inflation means you stood in the same place for a year.

Building wealth means growing the real number, not the nominal one. Measure your assets by what they can buy, not by the number in the account. That single shift in perspective changes every investment decision you make.