How much you can borrow for a Czech mortgage: DTI, DSTI and LTV

Two buyers with the same salary walk into two banks. One leaves with a pre-approval for a comfortable loan, the other with a smaller figure and a request for more paperwork. Neither bank broke a rule. The Czech system gives the central bank a say over how risky mortgage lending may become, and then leaves each lender to work out the rest.

To understand what you can borrow, it helps to separate three ideas that are often blurred: the loan against the value of the flat, the debt against your income, and the monthly payment against your income. Each has its own abbreviation, and each is treated differently today.

Three measures, one answer

The loan-to-value ratio (LTV) compares the loan with the value of the property. It limits how much of the price can be borrowed and therefore how much cash you need. Our explainer on how much deposit you need covers that side in detail.

The debt-to-income ratio (DTI) compares your total debts with your annual net income. A DTI of 8 means your debts are eight times what you earn in a year after tax.

The debt-service-to-income ratio (DSTI) compares the monthly payments on all your loans with your monthly net income. It is the measure closest to the question a household actually asks, which is whether the payment fits the budget.

The Czech National Bank (ČNB) sets limits and recommendations on all three, and banks follow them closely. The ČNB has used these tools since the mid-2010s and has tightened and loosened them over time. A bank that ignores them invites supervisory attention, so in practice they behave like rules.

Where the limits stand

The LTV recommendation is the one that stays in force: a maximum of 80% for owner-occupied housing, and 90% for applicants under 36 (as of 2026; check the ČNB). The income-based limits are different. The ČNB deactivated the DTI and DSTI limits in 2023, and its board kept the position unchanged in June 2026, so there is no official income multiple in force for ordinary home buyers (as of 2026; check the ČNB).

Many readers take that to mean banks will lend anything. They do not. The ČNB switched off a regulatory backstop, not the banks' own credit policies. A lender still has to show that the borrower can repay, because the Consumer Credit Act (zákon č. 257/2016 Sb.) obliges it to assess creditworthiness before it lends. It builds its own test, and the test is usually stricter than a newcomer expects.

What the bank's own test looks at

Every lender has its own method, and none publishes it in full. The ingredients are similar.

• Net income that can be proved. Salary on payslips, with the bank sometimes discounting bonuses and variable pay. The self-employed are assessed on taxable income from the tax return, not on turnover.
• Existing debts. Mortgages, consumer loans, leasing, and also credit cards and overdrafts, which many banks count at the limit rather than at the balance. Closing an unused card before applying can matter more than people expect.
• Household composition. Children and dependants raise the living costs a bank assumes.
• A stress test on the rate. Banks test whether you could still pay if the rate were higher at the next fixation, so the payment they check is not always today's payment.
• A cost-of-living floor. The bank deducts a minimum household cost from your income before it decides what is left for the loan. The method varies by lender.

The result is a maximum payment, and from the payment, a maximum loan for a given rate and term. Longer terms lift the loan size, because the payment is spread out, but a bank has its own limit on age at the end of the term, so the choice is not unlimited.

A hypothetical illustration

The following figures are hypothetical and only show how the ratios relate. They are not a forecast of what any bank will do.

Suppose a household has a net income of CZK 60,000 a month, which is CZK 720,000 a year. If a lender worked to a DTI of 8, a purely illustrative multiple and not a current rule, total debts would be capped at CZK 5,760,000. Now suppose the flat costs CZK 6,000,000. At 80% LTV the largest loan is CZK 4,800,000, and the buyer needs CZK 1,200,000 of own funds plus the costs of the purchase. At 90% (for a buyer under 36) the loan could reach CZK 5,400,000.

The two constraints work together. The lower of the loan allowed by the property and the loan allowed by the income wins, and the buyer's own money fills the gap. Change the income, the rate or the term, and the answer moves, which is why a calculator beats a rule of thumb. You can try the arithmetic with the borrowing estimator on Hypoteky.com and see the payment for a given rate with its mortgage calculator, though only the bank's assessment counts.

What moves your ceiling

The factors you can change, in rough order of effect, are the following.

Other debts. Paying off a car lease or a consumer loan frees capacity faster than a pay rise. Cancel unused credit limits as well.

The length of income history. A probation period or a very recent job change makes banks cautious. Some will wait until probation is over.

The own contribution. More cash lowers the LTV, which can lower the rate on offer as well as the loan.

The rate and fixation. A lower rate cuts the payment and so raises the sum the same income supports. Our guide to rates and fixation periods explains what sets the rate.

Residence and currency of income. A foreign applicant faces extra checks, as covered in what banks ask foreign borrowers.

Joint applications

Two applicants add their incomes, but they also add their debts, and both become liable for the whole loan. Banks often ask for a spouse or partner to join even if one income would suffice, because property in a marriage may fall into joint property. The details depend on the couple's property regime and the bank's policy, so ask the lender early. A guarantor is possible at some banks, though the guarantor's own obligations are assessed too.

Common mistakes

Treating the pre-approval as a promise is the first one. A pre-approval is conditional on the final valuation, on documents that still need checking and on your circumstances not changing. A new car loan taken between pre-approval and drawdown can undo it.

The second is shopping with one bank. Banks weigh the same file differently, and a refusal at one is not a verdict on you. Our companion piece on the mortgage application step by step shows when to compare, and whether to use a broker is worth settling at the same point.

The third is forgetting the costs around the loan. The sum you borrow is only part of the cash you need at closing, as the article on the real cost of buying a flat in Prague sets out.

Frequently asked questions

Is there a legal maximum multiple of income I can borrow in Czechia?

Not at present for an owner-occupied home. The ČNB deactivated its DTI and DSTI limits in 2023 (as of 2026; check the ČNB). Banks still apply their own affordability tests.

What is the maximum loan-to-value?

The ČNB recommends 80%, or 90% for applicants under 36, for owner-occupied housing (as of 2026; check the ČNB). A bank can set a lower ceiling.

Do the same rules apply to a buy-to-let loan?

No. Stricter ČNB recommendations apply to investment loans from 1 April 2026, including a lower LTV and a DTI cap. Read the definitions on the ČNB site.

Why did two banks give me different figures?

Each bank sets its own method for counting income, existing debts, household costs and rate stress. The same file can produce different results.

A practical next step

Before you ask any bank, list your net income by source, every loan and card limit with its monthly cost, and the number of dependants. Run the numbers through a calculator at two or three rates, then ask each bank what payment it would assume and how it counts your credit limits. The answers tell you more than the headline figure.

This is a general explainer, not legal, tax or mortgage advice.