Czech mortgage interest tax deduction explained: who can claim

Mortgage interest is one of the few housing costs for which the Czech tax system offers relief, and it is among the most misunderstood. Buyers hear that "interest is tax deductible" and assume they will get back a large part of what they pay. The real figure is capped, is applied to income, not to tax, and for many households it amounts to a modest sum.

This explainer covers who can claim, what counts, how much it is worth, and how to claim it. It describes the rule; it does not calculate your tax. Our guide to state support for first-time buyers places the deduction among the other forms of help, and this piece goes deeper on how the deduction itself works.

The basic rule

Under the Income Tax Act, a taxpayer can deduct from the tax base the interest paid on a loan used for their own housing need (as of 2026; check the Financial Administration). The housing need covers buying a flat or house, building or extending one, and repaying an earlier loan that was used for that purpose. The loan can be a mortgage or a loan linked to building savings. The deduction applies to the interest paid in the tax year, not to the principal.

The cap depends on when the housing need was acquired:

• From 1 January 2021: up to CZK 150,000 of interest a year for the whole household.
• Before 2021: up to CZK 300,000 a year.

Refinancing a loan does not change the date, so a household that refinances a pre-2021 loan keeps the older cap (as of 2026; check the Financial Administration). From the 2026 tax period, members of a housing cooperative who repay the cooperative's housing loan can also claim.

Why the saving is smaller than the interest

A deduction from the tax base reduces the income that is taxed. It is not a credit against the tax. If you deduct CZK 100,000 of interest and your income is taxed at 15%, you save 15% of CZK 100,000, which is CZK 15,000. You do not save CZK 100,000.

At the 150,000 cap the maximum saving at 15% is CZK 22,500 (150,000 × 0.15). Taxpayers whose income is high enough to reach the 23% rate on part of it may save more, because the deduction reduces the top slice first. The thresholds for the higher band are set each year, so check the Financial Administration for the current figure.

A second limit applies at the other end. The deduction can reduce the tax only down to what you owe. Employees and the self-employed with a low tax bill, or whose tax is wiped out by the taxpayer credit, may get little or nothing from it. The basic credit is CZK 30,840 a year in 2026 (as of 2026; check the Financial Administration). A low earner who has no tax to pay gets no benefit from the deduction.

Hypothetical examples

All figures below are hypothetical and only show the arithmetic.

Case	Interest paid in the year	Deducted (cap 150,000)	Saving at 15%
A	CZK 120,000	CZK 120,000	CZK 18,000
B	CZK 180,000	CZK 150,000	CZK 22,500
C	CZK 60,000	CZK 60,000	CZK 9,000

In case B, CZK 30,000 of interest exceeds the cap and gives no tax relief. A larger loan reaches the cap sooner: a balance of CZK 4,000,000 at a hypothetical 4% would produce about CZK 160,000 of interest in the first year, which is above the cap. In practice the interest falls as the principal is repaid, so the cap bites mainly in the first years of a large loan.

Who can claim

The deduction is for taxpayers, not for lenders or properties, and several conditions matter.

Tax residence. The claimant files a Czech tax return or has the annual settlement done by an employer, which usually means being a Czech tax resident. The test is a permanent home in Czechia or a habitual stay of at least 183 days in a calendar year; see Czech tax residency rules. A non-resident can generally claim it only if they are resident in another EU or EEA state and at least 90% of their total income comes from Czech sources (as of 2026; check the Financial Administration).

Own housing need. The loan has to serve the claimant's own housing. A loan for a buy-to-let flat does not qualify, whatever the interest. The tax side of letting is covered in tax on rental income.

A loan in the right form. Mortgages and similar housing loans from a bank or building society qualify. A private loan from a relative or an employer may have different rules, so check before assuming.

Documents. Lenders issue an annual confirmation of the interest paid, and the claimant keeps it with the tax records.

Couples and co-borrowers

The cap is per shared household, not per person. Where several adults are parties to the loan, the deduction is divided, normally in equal parts, and spouses may be able to allocate it differently (as of 2026; check the Financial Administration, since the wording on sharing is detailed). So a couple with a joint mortgage and a CZK 150,000 cap does not receive CZK 300,000 of deduction between them.

Our guide to joint mortgages explains how couples and co-borrowers share the loan, and the tax allocation can differ from the legal split of the debt. A tax adviser can say how it works in your case.

How to claim

There are two routes.

1. The annual settlement by the employer. An employee asks the employer to do the annual settlement by 15 February and gives the lender's confirmation. The employer applies the deduction.
2. The personal tax return. The taxpayer files by 1 April on paper, by 1 May electronically, or by 1 July with a tax adviser (as of 2026; check the Financial Administration). The confirmation is attached or kept on file.

The steps in the return are covered in how to file a Czech personal tax return, and the employee side in how Czech income tax works for employees.

How rates and refinancing interact with it

Higher interest rates raise the interest you pay and therefore the deduction, up to the cap. That does not make a rise in rates cheap. If a household pays CZK 25,000 more in interest and all of it is deductible at 15%, it recovers CZK 3,750 and is still CZK 21,250 worse off (25,000 minus 3,750). The hypothetical figures show why: the deduction softens a rise, it does not cancel it. To test a rate change, run both rates through the mortgage calculator on Hypoteky.com and subtract the tax effect yourself.

On refinancing, a new loan used to repay an old housing loan keeps the deduction in principle, and the date of the original housing need stays. See refinancing a Czech mortgage for when it pays off. For a first purchase, the first mortgage guide on Hypoteky.com walks through the steps of getting a loan.

What the deduction is not

• It is not a refund of interest.
• It is not a subsidy for investors.
• It does not apply to principal repayments.
• It does not remove the need for a tax return where one is required.
• It is not guaranteed to stay unchanged. The caps, the rates and the conditions are set in the law, and rules have changed more than once in the past few years, so check the Financial Administration for the current version.

Frequently asked questions

Can a foreigner claim the mortgage interest deduction?

A foreigner who is a Czech tax resident and meets the conditions can claim it. A non-resident generally cannot, except an EU or EEA resident with at least 90% of income from Czech sources. Tax residence depends on a permanent home or at least 183 days of stay in a calendar year.

Is the deduction for principal as well as interest?

No. Only interest paid on a qualifying housing loan is deductible.

How much is the maximum saving?

At the 15% rate, about CZK 22,500 a year on the CZK 150,000 cap. The pre-2021 cap of CZK 300,000 allows a larger deduction (as of 2026; check the Financial Administration).

Does refinancing change the cap?

No. Refinancing does not change the date the housing need was acquired, so the original cap continues to apply.

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