How this filing check works
Luxembourg filing obligations depend on income type, amount, withholding, residence, tax cards, and taxation elections—not salary alone.
- Income above €100,000 is a common mandatory-assessment trigger.
- An additional tax card can trigger Form 100 above €36,000 for Classes 1/2 or €30,000 for Class 1a.
- For residents, more than €600 of net income not subject to withholding can trigger assessment.
- Form 163 is generally a refund procedure for employees or pensioners who are not required to file Form 100.
- Property-loan interest claims generally require Form 100 rather than Form 163.
This tool cannot classify every income category or treaty situation. Gross amounts and net taxable amounts are not interchangeable. A filing request from the ACD always takes priority.