Personal taxation · Luxembourg
Mortgage interest deduction calculator: 2025 cap
For 2025, the cap depends in particular on the year the home first became available for use and on the household units allowed. The calculator first deducts subsidies from the interest and then applies the relevant cap. It only handles a main residence and eligibility conditions you have already checked.
Financial Services Luxembourg · Licensed accountant · Head of the firm: Mickaël LOC. Editorial update: .
Ceiling on main home mortgage interest
Tax year 2025 only. Enter the amounts according to the method and scope explained on this page.
Local calculation, with no account and no amounts transmitted. The contact form is separate. Reloading the page clears your entries.
The periods covered
| Situation for 2025 | Reference regime | Example year of first availability |
|---|---|---|
| Before availability | Net interest without a cap under the statutory conditions | Year not yet reached |
| Year of availability and the following year | Net interest without a cap | 2024 or 2025 |
| Second to fifth following year | EUR 4,000 per unit allowed | 2020 to 2023 |
| Sixth to tenth following year | EUR 3,000 per unit allowed | 2015 to 2019 |
| Beyond that | EUR 2,000 per unit allowed | 2014 or earlier |
Units are not simply the number of occupants
The increase for a spouse or partner depends on joint taxation, and the increase for a child on the corresponding entitlement. The calculator asks you for a number of allowed units that has already been checked; it does not infer eligibility from a person living in the home.
A non-resident must in particular examine access to the deduction and assimilation to resident taxpayers where it is required. The loan must be linked to the main residence concerned.
Fictitious example
For a home available since 2023, two allowed units give a cap of EUR 8,000 in 2025. Interest of EUR 9,500 less a subsidy of EUR 500 gives EUR 9,000 net; the amount taken into account in this scenario is limited to EUR 8,000.
This amount is a deduction from the tax base, not a tax saving of EUR 8,000. The tax effect must be calculated in a second step on the complete file.
Excluded cases
A change of home or of use during the year, several homes, uncertain ownership shares and special regimes require a review. Repaid capital and other loan costs are not included in the interest amount you enter.
The year of first availability is not necessarily the year of the first repayment. The calculator remains limited to 2025 even though some rules have applied since 2024.
The firm’s other tax engagements
Depending on your situation, the firm also handles tax, VAT and payroll, the regularisation of late tax filings and assistance during a tax audit. Fees are listed in the firm’s fee grid.
Official sources and scope
The rules apply to the year and profile concerned. Examples flagged as fictitious explain a method; they are not an individual validation. The documents and options of your file are covered by a separate engagement.