Self-employed workers in Luxembourg: how to adjust your contribution base for 2026?

Why adjust your contribution base in 2026?

During the first quarter of 2026, the Centre commun de la sécurité sociale (CCSS) sent a letter to every business owner registered as self-employed, stating the amount of their annual contribution base.

👉 This base serves as a reference for calculating your social security contributions in Luxembourg.

However, it does not always reflect your actual or projected income.

When should it be amended?

You should consider making an adjustment if:

• your income has significantly increased or decreased
• your business activity is evolving (growth, slowdown, change of status)
• the communicated basis is outdated or inaccurate

An incorrectly adjusted basis may result in:

• excessively high contributions (impact on personal cash flow)
• or a significant adjustment at a later date

How to adjust your contribution base in Luxembourg?

The procedure is simple but requires you to take the initiative:

1. Order the adjustment form from the CCSS website
2. Complete the form with your projected income for 2026
3. Send the application to the CCSS

👉 We recommend that you complete this process as soon as possible to avoid late adjustments.

Did you know? A tax allowance that’s often overlooked!

As a self-employed person in Luxembourg, you may be eligible for a tax allowance (known as a ‘special expense’).

This corresponds to social security contributions paid personally.

How do you claim it?

The application must be submitted to the ‘Administration des contributions directes’.

Along with the following documents:

• a copy of your CCSS statements (front and back)
• proof of payment from your personal account

👉 This benefit reduces your taxable income.

Need help with these steps?

Adjusting your taxable income and optimising your tax position can quickly become complicated

Our teams are here to help you:

• calculate your taxable income as accurately as possible
• plan for your tax liabilities
• ensure your dealings with the Luxembourg authorities run smoothly

👉 Feel free to contact us for personalised support.