Tax withholding card: how to read and correct it
Skimming?
We've prepared the shortcut for you.
This is for you if
- You have just received your first tax card and the abbreviations (FD, DS, CIS...) mean nothing to you.
- Your net salary does not look like what you expected.
- You got married, entered a civil partnership, separated, or had a child this year.
- You have two employers, or a salary and a pension.
- You are a cross-border worker (France, Belgium, Germany): your card comes from the RTS Non-residents office and several rules change.
Not for you if you are a temporary worker paid €25 gross per hour or less: since 2022, you do not need a tax card: a flat withholding rate applies, set at 7.5% since 2025 (10% previously) (Guichet.lu).
Your tax card box by box
Here is what the 2026 tax card contains, based on the specimen published by the ACD (ouvre dans un nouvel onglet). The deduction amounts appear annually, monthly, and daily.
| Box | What it means | What you should check |
|---|---|---|
| Competent office | The RTS office that issued the card, according to your municipality of residence (RTS Non-residents if you live abroad) | This is who you write to for corrections |
| Tax card ID, valid from | Tax card number (the issue date is coded after the "E") and effective date | That the date matches your change of situation |
| Identification number | Your 13-digit national identification number | No wrong digits |
| Address, country | Your domicile | Resident or non-resident: everything else depends on this |
| Employment | Employer's ID number and name, municipality of the workplace | One card per employer or pension fund |
| Tax class | 1, 1a or 2: the scale applied to your main tax card | See our guide on tax classes |
| Withholding rate | A fixed rate (additional card) or a calculated rate (married couple who chose individual taxation, married non-resident who requested assimilation) | That a fixed rate does not apply to your main salary |
| FD | Flat-rate travel expenses: €99 per distance unit, first 4 units not counted, up to €2,574 per year maximum (2026) | That it is not blank if you commute |
| AC/AE | Spousal allowance (AC, €5,520 per year: the extra-professional allowance of €4,500 plus the flat rates of €540 and €480, not to be added a second time), automatically entered when both collectively taxed spouses have a salary; extra-professional allowance (AE) in a few specific cases | Only for collectively taxed couples |
| CE | Extraordinary charges: childcare costs, child outside your household (up to €5,424 per child per year)... | Entered upon request |
| DS | Special expenses beyond the flat rate: home savings, pension planning, insurance, consumer loan interest | Entered upon request, to be renewed every year |
| FO | Actual professional expenses, if you exceed the flat rate | Supporting documents attached |
| AMVP | Allowance for remaining in active employment, since 2026: up to €9,000 per year (€750 per month) if you meet the conditions for early retirement pension and keep working, until you draw your pension or reach the legal retirement age at the latest | Certificate of eligibility |
| FFO, FDS | Flat rates for professional expenses (€540 per year) and special expenses (€480 per year) | On a main tax card, they are already integrated into the scale and generally do not appear |
| CIS, CIP, CIM | Tax credit for employees, pensioners, single parents: yes or no | CIS "yes" if you are an employee, CIM only in class 1a |
The details on credits can be found in our guide on tax credits.
Resident employee: a card updated almost all by itself
Do you live in Luxembourg? Your tax card follows your life with mostly no steps required: the ACD updates it automatically, on average within 30 working days (indicative timeframe), after a change of employer, address, or marital status declared to your municipality, or a household change reported to the Children's Future Fund (CAE) (Guichet.lu).
Travel expenses (FD) are entered automatically, but they are based on the municipalities known to the ACD: at trigger, this is the box we advise checking first, especially after changing your workplace.
Take Léa, single, around €60,000 taxable income per year, living 14 distance units from her workplace (fictional figures for the example). Deduction: (14 − 4) × €99 = €990 per year, or €82.50 per month. This income places her in the 39% bracket, which is 41.73% including the 7% employment fund contribution. Once FD is entered, her withholding decreases by approximately 82.50 × 41.73% = €34 per month. Calculation details for distance units: our guide on travel expenses.
Cross-border worker: your tax card comes from the RTS Non-residents office
Do you live in France, Belgium, or Germany? Your tax card is issued by the RTS Non-residents office. Only a change of employer or retirement will update it automatically: a marriage, separation, or move is up to you to report, online via the National Register of Natural Persons (RNPP) on MyGuichet.lu or using form 164 NR (Guichet.lu).
If married, you generally remain in class 1, even with children: this has been the rule since 2018 (Article 157bis of the Income Tax Law, ACD). You can obtain a calculated rate like a resident couple if you request tax assimilation: at least 90% of your worldwide income taxable in Luxembourg, or less than €13,000 in income not taxable in Luxembourg (specific Belgian rule: more than 50% of professional household income) (ACD).
If married and assimilated, your tax card can then display a personalized rate instead of a class. If single and assimilated, you keep your class 1 or 1a. To calculate what this changes, test the cross-border worker simulator.
Couples or 2nd job: main tax card and additional tax card
You receive one tax card per employer or pension fund. The main card goes to the highest and most stable salary and applies the scale for your class. The others are additional cards, with a fixed rate: 33% in class 1, 21% in class 1a, 15% in class 2, applied to gross income reduced by social security contributions (ACD).
- Married resident couple: a single main card for the household (class 2), for the higher-earning spouse. The other receives an additional card at 15%, on which the spousal allowance (AC: €5,520 per year, or €460 per month) is generally entered. If Sophie earns €2,000 per month after social security contributions on this card: (2,000 − 460) × 15% = €231 withheld each month.
- 2nd job: Nina, in class 1, earns €600 taxable per month in a second job. Withholding: 600 × 33% = €198 per month. The fixed rate can be reduced upon request, by attaching your last 3 payslips with the note "please reconsider my rate at the lowest possible level". Note: with a reduced rate, the ACD automatically adjusts your year via a special annual adjustment, which may also request additional tax (ACD).
- Wrong main card (it is assigned to your secondary job): request conversion with the note "please reconsider the main card".
These adjustments change the advance payment, not the final tax (Guichet.lu). Married couples: you can also jointly request individual taxation, via the online process "Request for individualization / RTS rate", form 166 or tax return (form 100), up until 31 December of the following year. At trigger, we look at the main card first: it has the biggest impact on net pay.
If your situation changes
| Event | Resident | Cross-border worker |
|---|---|---|
| Marriage | Automatic update via your municipality, class 2 from the date of marriage | Class 1; couple rate only with assimilation |
| Civil partnership (PACS) | Tax card unchanged (class 1 or 1a): collective taxation must be requested in the tax return, if the partnership and joint domicile cover the entire year | Same, plus assimilation conditions |
| Birth | Updated in principle via the CAE; otherwise form 164 R | Form 164 NR |
| Separation, divorce | Updated via your municipality; class 2 possible for the 3 tax years that follow, subject to conditions | Online RNPP or 164 NR; same transitional class 2 possible, subject to conditions |
| 2nd job | Additional card issued automatically upon registration | Same |
| Relocation | Updated automatically; your RTS office may change | If you move to Luxembourg, you become a resident |
Sources: Guichet.lu (residents and non-residents), ACD (partnership).
Checking and correcting your tax card, step by step
Obtain your tax card
It arrives by post: it cannot be collected from the RTS office. To also receive it in PDF format, subscribe to eDelivery in your private MyGuichet.lu space ("Subscription to ACD mail"): only mail sent after subscription will appear there. You no longer need to hand it to your employer since 2022, as they receive it electronically.
Check every box upon receipt
Compare with the table above: class, rate, FD, credits.
Fill in form 164 R or 164 NR
Form 164 R 2026 (ouvre dans un nouvel onglet) (resident) or 164 NR 2026 (ouvre dans un nouvel onglet) (non-resident), one per person. Attach the documents listed on the last page (marriage certificate, court ruling, payslips...).
Send it to the competent RTS office
Not to the tax office: it goes to the RTS office of your municipality of residence, or the RTS Non-residents office. Contact details on the ACD RTS offices page (ouvre dans un nouvel onglet) and in our guide find your tax office.
Check your next payslip
No timeframe is guaranteed for the new card (the ACD announces an average of 30 working days for an automatic update). Your employer applies it from its effective date and can correct previously paid months.
Adjust the entire year if necessary
Any overwithheld amount can be recovered via annual adjustment (form 163) or tax return (form 100), by 31 December of the following year at the latest.
Common mistakes
- Believing that a civil partnership changes your tax card: it does not move, the benefit is recovered in the tax return.
- Leaving the FD box blank even though you commute every day.
- Forgetting that entered deductions (DS, CE) are valid for one year only: the request must be renewed.
- Keeping the main tax card on the minor job and facing 33% on the major salary.
- Married cross-border worker: assuming class 1 is due to an ACD error, whereas it is the standard rule without assimilation.
What could change
Bill No. 8676, introduced on 6 January 2026, provides for a single tax class starting 1 January 2028: all taxpayers in class 1 or 1a and couples marrying or entering a civil partnership from 2028 would move to it, while couples married or in a civil partnership before 2028 would keep joint taxation during a 25-year transition. The Finance Committee of the Chamber of Deputies adopted its report on 29 September 2026, but the bill is not voted: your 2026 tax card applies current rules.
Frequently asked questions
Without a tax card, withholding is calculated under class 1, without being lower than 33%. If nothing has arrived 30 working days after your first working day, contact your RTS office and notify your employer (Guichet.lu).
In principle no: introduced on 1 May 2021 and generalized in 2023, tax cards are multi-year and remain valid as long as no information changes. Exception: tax cards issued for fixed-term contracts (ACD).
Either it is an additional tax card (2nd job), or you are married and your couple chose individual taxation, or you are a married non-resident and requested assimilation: in these cases, the ACD enters a calculated rate instead of a tax class.