Luxembourg Tax Classes 1, 1a and 2: Marriage On the Payslip

Luxembourg's income tax schedule has an unusual number of narrow bands, rising in two percentage point steps from 8% to 38% before flattening into wider bands at the top. That granularity makes the rate schedule smooth, and it also makes the class system decisive, because the class determines how the schedule is applied.

The three classes

Class 1. Single taxpayers without children. The schedule is applied directly to individual income.
Class 1a. Single parents, and taxpayers aged sixty five and over. A modified schedule with a larger initial exempt portion, sitting between the other two in effect.
Class 2. Married couples and civil partners electing joint taxation. Household income is divided by two, the schedule is applied to the half, and the resulting tax is doubled.

That splitting mechanism in class 2 is the whole point. Because the schedule is progressive, taxing two halves of a household income produces less tax than taxing the whole, and the advantage is largest when the two incomes are most unequal.

What the difference is worth

Household	Class	Effect
Single, no children	1	The heaviest treatment, no splitting
Single parent	1a	A larger exempt portion plus a single parent credit
Married, one earner	2	The largest advantage, since the whole income is split
Married, two equal earners	2	Little advantage from splitting, because the halves resemble the individual incomes
Married non-residents	1 by default	Class 2 available on request where enough income is taxable in Luxembourg

The last row matters enormously, because roughly half of Luxembourg's workforce lives across a border. Non-resident married taxpayers were moved to class 1 by default in a reform, with the option to request class 2 treatment by opting for assimilation to resident status, which requires a defined share of household income to be taxable in Luxembourg.

The option has to be exercised, and the calculation of whether it is worthwhile depends on the spouse's income in the country of residence. Many cross-border couples have found themselves worse off after the change without realising an election was available.

The tax card

Luxembourg issues a fiche de retenue d'impôt, a tax card, stating the class and any deductions the employer should apply. The employer withholds accordingly. Without a card, withholding is at a punitive default rate.

The card also carries individual deductions that have been registered, and it is worth checking, because items such as interest on a home loan, certain insurance premiums and private pension contributions can be entered on it and applied monthly rather than waiting for the annual return.

Deductions worth registering

Private pension contributions under the prévoyance-vieillesse regime, deductible up to an annual ceiling.
Home loan interest on a principal residence, deductible within limits that decline as the property ages.
Insurance premiums and home savings contributions, deductible within a combined annual ceiling.
Commuting costs, granted as a distance based deduction rather than an actual cost claim.
Childcare and domestic help costs, deductible up to a monthly limit.

What sits alongside income tax

Employee social contributions run at around 11.05% of gross up to a ceiling of roughly 116,000 euros, covering pension, health and dependency insurance. That is low by continental standards and is a substantial part of why Luxembourg net pay compares so well.

Luxembourg also operates a solidarity surcharge on income tax funding the employment fund, which raises the effective rate slightly above the schedule. Set against a high salary level and a low contribution rate, the country remains one of the stronger performers for take-home pay in Europe, as the figures in 100,000 euros in ten euro countries show.