Real Rate of Return -- How to Calculate If You Are Actually Earning

The Number That Actually Matters

Your bank shows 5% interest on your savings. Your broker reports a 12% gain on your ETF portfolio. Your treasury bonds paid 6.5% last year. These numbers feel good — but they are all lies of omission.

They are nominal returns — they ignore inflation and taxes. The number that actually tells you whether you are getting richer or poorer is the real rate of return.

The Formula

The real rate of return accounts for both inflation and taxes:

Step 1: Calculate after-tax return

After-tax return = Nominal return × (1 - tax rate)

In Poland, the capital gains tax (Belka tax) is 19%.

Step 2: Calculate real return

Real return = ((1 + after-tax return) / (1 + inflation rate)) - 1

For a quick approximation:

Real return ≈ After-tax return - Inflation rate

Real Examples with Polish Numbers

Example 1: Bank Savings Account

• Nominal rate: 5.0% (a good mBank or ING savings account in 2026)
• After Belka tax: 5.0% × 0.81 = 4.05%
• Inflation: 4.5%
• Real return: 4.05% - 4.5% = -0.45%

You are losing money. For every 10,000 PLN saved, you lose about 45 PLN of purchasing power per year.

Example 2: COI Treasury Bonds (Year 2+)

• Nominal rate: CPI + 1.25% = 4.5% + 1.25% = 5.75%
• After Belka tax: 5.75% × 0.81 = 4.66%
• Inflation: 4.5%
• Real return: 4.66% - 4.5% = +0.16%

Barely positive, but positive. You are at least preserving purchasing power. With lower inflation, the real return improves.

Example 3: Global Equity ETF

• Nominal return: 10% (historical average for MSCI World)
• After Belka tax on realized gains: 10% × 0.81 = 8.1%
• Inflation: 4.5%
• Real return: 8.1% - 4.5% = +3.6%

Solid real growth. Note: if you do not sell, you defer the tax, making the effective real return even higher.

Example 4: Cash Under the Mattress

• Nominal return: 0%
• Inflation: 4.5%
• Real return: -4.5%

10,000 PLN hidden at home becomes worth only 9,550 PLN in purchasing power after one year. After 10 years, it is worth roughly 6,400 PLN in today's terms.

Example 5: Rental Property in Warsaw

• Gross rental yield: 5.5%
• After expenses and 8.5% ryczalt tax: ~4.5% net yield
• Property appreciation: ~5% per year
• Total nominal return: ~9.5%
• After taxes on appreciation (deferred): ~9.5%
• Inflation: 4.5%
• Real return: ~+5.0%

Real estate benefits from deferred capital gains tax — you only pay when you sell, and after 5 years of ownership, property sales are tax-free in Poland.

The Belka Tax: Poland's Investment Tax

Named after former Finance Minister Marek Belka, the 19% flat tax applies to:

• Bank deposit interest
• Bond coupon payments
• Stock dividends
• Realized capital gains from selling stocks, ETFs, and bonds
• Crypto gains

It does not apply to:

• Unrealized gains (paper profits you have not sold)
• IKE and IKZE accounts (tax-advantaged retirement accounts)
• Property sold after 5 years of ownership

IKE and IKZE: Tax-Free Real Returns

Poland offers two tax-advantaged accounts:

• IKE (Indywidualne Konto Emerytalne): No Belka tax on gains if you withdraw after age 60. Annual contribution limit ~24,000 PLN (2026).
• IKZE (Indywidualne Konto Zabezpieczenia Emerytalnego): Contributions are tax-deductible, gains taxed at flat 10% on withdrawal. Annual limit ~10,000 PLN.

Using IKE eliminates the Belka tax entirely, dramatically improving your real return:

• ETF in regular account: 10% - 1.9% tax - 4.5% inflation = +3.6% real
• ETF in IKE account: 10% - 0% tax - 4.5% inflation = +5.5% real

That difference compounds massively over 20-30 years.

Common Mistakes When Calculating Returns

Mistake 1: Ignoring Inflation Entirely

Many people see "5% interest" and feel satisfied. But if inflation is 5%, they are earning nothing. Always subtract inflation.

Mistake 2: Forgetting About Tax

A 6% return is not 6%. It is 4.86% after Belka tax. Always apply the 19% haircut (unless using IKE/IKZE).

Mistake 3: Using the Wrong Inflation Number

Personal inflation can differ from CPI. If you spend heavily on housing, food, and education — all of which have inflated faster than headline CPI — your real return is even lower than calculated.

Mistake 4: Not Accounting for Fees

Fund management fees (TER — Total Expense Ratio), brokerage commissions, and currency conversion costs all reduce your real return. A typical ETF charges 0.1-0.5% annually.

True real return = Nominal return - Tax - Inflation - Fees

How to Track Your Real Return

Calculating real returns manually across multiple accounts is tedious. You need to:

1. Aggregate all accounts (banks, brokerages, bonds, crypto)
2. Calculate total portfolio return
3. Apply tax adjustments
4. Subtract current inflation

Freenance automates this by connecting to your accounts at mBank, ING, PKO, Revolut, and XTB. It calculates your total net worth and shows how your portfolio performs relative to inflation — giving you the honest number instead of the flattering one.

A Simple Decision Framework

Key Takeaways

• Nominal returns are misleading. Always calculate after inflation and taxes.
• The Belka tax (19%) takes a significant bite from every investment return in Poland.
• Use IKE/IKZE accounts to eliminate or reduce tax drag.
• At 4.5% inflation, you need at least 5.6% nominal return just to break even after tax.
• Track your real return with Freenance to know whether you are actually building wealth or just watching numbers go up.