DTI (debt to income)
DTIDebt to Income: an applicant's total debt expressed as a multiple of their net annual income. The ČNB limit on DTI was deactivated on 1 January 2024. The ČNB now only recommends extra caution above 8, and from 1 April 2026 it recommends a DTI of no more than 7 for investment mortgages. Banks set their own internal ceilings, usually 8–9.5 times income.
Example
A net income of CZK 60,000 a month comes to CZK 720,000 a year. With an internal DTI ceiling of 8, total debt can reach CZK 5,760,000; for an investment mortgage with the recommended DTI of 7, only CZK 5,040,000. A CZK 5,000,000 mortgage over 30 years at 5.00 %, with a payment of CZK 26,841, would only just fit within the usual DSTI threshold of 45 %: it needs a net income of at least roughly CZK 59,700.
In practice
Banks put every debt into DTI, including balances on consumer loans and usually credit card limits, not just the new mortgage. For a couple, both incomes are added together. DTI most often holds back large loans in Prague, where new-build flats cost roughly CZK 146–150 thousand per m² and prices are rising faster than wages. Calculating DTI from gross income is a common error.
How it differs
DSTI tracks monthly payments, whereas DTI looks at the size of the debt regardless of rate and term. A longer term therefore improves DSTI but leaves DTI where it was. LTV weighs the loan against the value of the collateral and is the only one of these ratios for which the ČNB sets a limit on owner-occupied housing.
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