How to Calculate Real Return

Formula

real return = (1 + nominal return) / (1 + inflation) − 1

• nominal return: the investment’s return over the period as a decimal (0.40 for 40%), after tax and fees
• inflation: the CPI change over the same period as a decimal (0.3151 for 31.51%)
• real return: the result; when it is negative, your money buys less even if it grew

This is the Fisher equation. For Türkiye, take inflation from the consumer price index (CPI) that TurkStat (TÜİK) publishes every month. For a one-year investment, use the annual change: in August 2026 it was 31.51%, while the twelve-month average change was 31.79%.

Step-by-step example

An investment of 100,000 TRY grew to 140,000 TRY from August 2025 to August 2026:

1. Find the nominal return: (140,000 − 100,000) / 100,000 = 40%.
2. Take inflation: the annual CPI change for August 2026 is 31.51% (TurkStat).
3. Move the initial value to today’s prices: 100,000 × (1 + 0.3151) = 131,510 TRY.
4. Find the real return: 140,000 / 131,510 − 1 ≈ 6.46%. This is the same as (1.40 / 1.3151) − 1.

In today’s prices, the investment’s purchasing power grew by 8,490 TRY. If you enter 131,510 as the initial value, 140,000 as the final value and 1 year as the period in an investment return calculation, the total return is the real return. The 40% return in the example is an illustration, not a market return.

Real return by nominal return

100,000 TRY for 1 year, inflation 31.51% (CPI, August 2026):

The 34% row is the net return of a 1-year Turkish lira deposit at a gross 40% after 15% withholding. When the nominal return is below inflation, the real return is negative.

A common mistake: subtracting inflation

Subtracting inflation from the nominal return (40 − 31.51 = 8.49 points) overstates the real return; the correct result is 6.46%. The higher the inflation, the wider the gap between the two methods. Also make sure both rates cover the same period: do not compare a yearly return with a monthly CPI change.