Many Belgian cross-border workers count “approximately”: a Google Sheet, memory, an HR email. It works until the day a half-day is missing — or a trip was forgotten.
Again: this is not tax advice. It is an operational method so you do not lose the thread.
A useful mental rule
For every working day, ask one question: did I work that day outside Luxembourg in a way that may count toward the threshold?
If the answer is yes (even for a half-day), log it the same day. Delay is the counter’s enemy.
What often enters the log
- Telework from home in Belgium.
- Half-days — they count too; ignoring them skews the total.
- Some business trips outside Luxembourg, depending on context.
What usually does not
- Leave / sick days (you are not working).
- Days you are physically at the office in Luxembourg.
- Non-working weekends.
Exact borders depend on the rules for your situation — which is why a clear log beats approximations.
Minimal routine (2 minutes in the morning)
- Open the log.
- Pick the day type.
- Check the ring / remaining allowance.
- Move on.
With Telework Tracker. One tap logs the day; the ring advances; alerts warn before the edge. On Pro, office presence can be reconciled with the log — never auto-edited for you.