In Polish: DSTI
This is the word you will see in bank documents.
Definition
DSTI (debt service to income) is the ratio of the monthly instalments of all your debts to your monthly net income, in per cent. The bank includes the new mortgage calculated with a buffer, other loans and a charge for credit limits. Recommendation S of the Polish Financial Supervision Authority (KNF) gives 40% as a reference point for income up to the average wage in the province and 50% above it.
What it means for you
DSTI sets the highest instalment the bank will accept for your income, and so indirectly the loan amount. Every other instalment, even for a phone bought in instalments, leaves less room for the mortgage. Moving from the 40% to the 50% threshold raises the loan amount by a quarter, so it matters how the bank compares your income with the average wage.
Full entry in Polish, with a worked example and sources
Frequently asked questions
What share of income can go on a mortgage instalment in Poland?
Under Recommendation S, usually up to 40% of net income for income up to the provincial average and up to 50% above it. All instalments count, and the mortgage instalment is calculated with a buffer.
Does a credit card limit count towards DSTI?
Yes. The bank adds a monthly charge on the whole card limit and overdraft, usually a few percent of the limit, even if you do not use it.
What is the difference between DSTI and DTI?
DSTI compares monthly instalments with monthly income. DTI, in the international sense, compares the whole debt with annual income. Polish texts sometimes mix up the abbreviations.
Related terms
Definitions are simplified and reflect Polish law and bank practice as of October 2026. Where every word matters, the Act and your loan agreement decide. Figures in examples are indicative and are not a bank offer. The Polish version of each entry has worked examples and sources.
Other terms in “Creditworthiness and down payment”