WIBOR — what it is and how it affects your loan

Definition

WIBOR (Warsaw Interbank Offered Rate) is the reference interest rate in the Polish interbank market. It represents the price at which commercial banks are willing to lend money to each other. It is the basis for interest rates on most mortgages in Poland.

How WIBOR affects your installment

The interest rate on a variable-rate mortgage consists of two elements:

Interest rate = WIBOR + bank margin

Example:

• WIBOR 3M: 5.80%
• Bank margin: 2.00%
• Interest rate: 7.80%

The margin is fixed for the entire loan period. WIBOR changes — and it's what causes installment increases or decreases.

Types of WIBOR

The most popular in mortgages are WIBOR 3M and WIBOR 6M.

WIBOR vs NBP rates

WIBOR follows the NBP reference rate but is not identical to it. Usually WIBOR is slightly higher than the reference rate because it includes credit risk between banks.

When MPC raises rates → WIBOR rises → Your installment rises. When MPC lowers rates → WIBOR falls → Your installment decreases.

WIRON — WIBOR's successor

Since 2025, there's an ongoing process of replacing WIBOR with the WIRON (Warsaw Interest Rate Overnight) indicator. WIRON is based on actual overnight transactions, not bank declarations. For borrowers, this usually means a lower base indicator — but banks may compensate with higher margins.

How much does a WIBOR change cost you per month?

Loan 400,000 PLN, 25 years, margin 2%:

The difference between WIBOR 2% and 7% is over 1,200 PLN monthly.

How Freenance can help

Freenance helps monitor WIBOR's impact on your finances:

• Loan installment tracking and its changes over time
• Scenario simulation — what happens when WIBOR rises/falls
• Impact on Runway — how installment changes affect your safety cushion

👉 Monitor your finances with Freenance — freenance.io