# Exceeding 34 days: what actually happens

HTML: https://teleworktracker.app/en/blog/exceeding-34-days-belgian-tax-return.html
French: https://teleworktracker.app/blog/depasser-34-jours-consequences-declaration-belge.md
Not tax advice.

## Someone asked: are only the days beyond 34 taxed in Belgium?

**Answer.** No. Not a slope — a **step**. Below the threshold: usual Luxembourg taxation of work-related pay. Beyond: pay for **all** days worked outside Luxembourg can become taxable in the country of residence, **from the first** of those days — not just day 35.

Illustration (order of magnitude, ~220 working days): 34 days → 0% of pay switched; 35 days → ≈ 16%. That is **not** the extra tax: the scale and family situation decide.

## Someone asked: do I file in both countries?

**Answer.** A Belgian resident employed in Luxembourg already files in Belgium. On exceedance, the **split** changes. Boxes often cited: **1250 / 2250**. The part taxed in Luxembourg vs Belgium must match a justifiable day count. Public sector: own rules.

## Someone asked: does the employer have work to do?

Yes: allocation between states, withholding, possible Belgian filing duties, documents for the employee. That is why many employers tightly frame telework.

## Someone asked: how far back can a tax audit go?

Ordinary personal-income-tax reassessment windows apply (several years depending on the case). Without a contemporaneous log, the split becomes a guess.

## Someone asked: does a tax breach switch social security?

**Answer.** Not automatically. Tax counter (days) ≠ social counter (%). See [two thresholds](https://teleworktracker.app/en/blog/social-security-telework-threshold-cross-border.md).

## Someone asked: is my ceiling really 34?

Not if part-time or incomplete year. [Proration](https://teleworktracker.app/en/blog/prorated-34-day-threshold-part-time.md).