Real Rate of Return Calculator

What is the real rate of return?

The real rate of return measures how much your purchasing power actually grew after accounting for inflation and taxes. A positive nominal return can still leave you worse off if inflation and capital gains taxes erode most of the gain.

Use this calculator when you know your starting balance, ending value, holding period, expected inflation, and an estimated capital gains tax rate. To analyze raw performance before inflation and taxes, start with the percentage return calculator or the CAGR calculator.

Real rate of return formula

The Fisher equation links after-tax nominal growth to real purchasing power growth:

Where $R_{\text{after-tax}}$ is the compound annual after-tax return and $\pi$ is the annual inflation rate.

Step-by-step calculation

1. Compute the annual nominal return from starting and ending values over the holding period:
   $$R_{\text{nominal}} = \left(\frac{V_f}{V_i}\right)^{\frac{1}{n}} - 1$$
2. Estimate capital gains tax on profits only, then derive the after-tax ending value and annual after-tax return:
   $$T = \max(0, V_f - V_i) \times \text{tax rate}$$
   $$R_{\text{after-tax}} = \left(\frac{V_f - T}{V_i}\right)^{\frac{1}{n}} - 1$$
3. Adjust the after-tax return for inflation to get the real rate, then project real purchasing power:
   $$V_{\text{real}} = V_i \times (1 + R_{\text{real}})^n$$

Worked example

Suppose you invested $10,000, the position grew to $12,000 after one year, inflation was 3%, and you estimate a 15% capital gains tax on the $2,000 profit.

1. Nominal return: ($12,000 / $10,000) - 1 = 20.00%
2. Tax: $2,000 × 15% = $300, leaving $11,700 after tax
3. After-tax return: ($11,700 / $10,000) - 1 = 17.00%
4. Real return: (1.17 / 1.03) - 1 ≈ 13.59%
5. Real purchasing power value: $10,000 × 1.1359 ≈ $11,359 in today's dollars

Why real return matters for financial planning

• Inflation reduces what a dollar can buy, so nominal gains may not increase living standards.
• Taxes are typically assessed on nominal gains, which can make effective tax burdens heavier during high-inflation periods.
• Retirement planning should target real returns so projected withdrawals preserve purchasing power decades later.

Frequently asked questions