Telework TrackerThe 34-day threshold is communicated everywhere as a fixed number. It is not. It is a reference ceiling, calibrated for a full-time employee present from 1 January to 31 December. Luxembourg's circular of 24 June 2026 restated this explicitly, with an example that gives pause: an employee at 75% hired on 1 October only has 6 days.
Six days is not a quota — it is a constraint. And plenty of cross-border workers in that position still reason with 34 in mind.
Calculation reference points
- Reference ceiling
- 34 days — full time, full year
- Factor 1
- Occupation rate
- Factor 2
- Contract duration within the year
- Assessment period
- Calendar year
- Official example
- 75% from 1 Oct → 6 days
The principle: two reductions that multiply
Proration works on two independent axes, and they compound:
- The occupation rate — a half-time employee does not work as many days as a full-timer, so the ceiling follows.
- The contract's duration within the calendar year — a September start or a March departure does not give a full annual quota.
These two reductions do not add up: they multiply. That is why an apparently ordinary situation — a 75% contract starting in the last quarter — ends up with such a low ceiling.
34 is the theoretical maximum. Your own number is almost always lower.
The formula
Personal threshold = 34 × occupation rate × (months covered by the contract ÷ 12)
Applied to the official example: 34 × 0.75 × 3/12 = 6.375 → 6 days. The rounding used there goes down, which is also the prudent reading: better to give up a theoretical half-day than to discover a one-day breach.
Eight worked examples
| Situation | Rate | Period | Threshold |
|---|---|---|---|
| Full time, full year | 100% | 12 months | 34 |
| Four-day week | 80% | 12 months | 27 |
| Three-quarter time | 75% | 12 months | 25 |
| Half time | 50% | 12 months | 17 |
| Full time, starting 1 July | 100% | 6 months | 17 |
| Full time, leaving 31 March | 100% | 3 months | 8 |
| 75%, starting 1 October | 75% | 3 months | 6 |
| Half time, leaving 30 April | 50% | 4 months | 5 |
Half time across the full year 17 days
Half the generic ceiling. One telework day per fortnight is enough to use it up.
75%, starting 1 October 6 days
Six days for a quarter: two a month, training and business trips included.
Change of working time during the year
The trickiest case is an employee whose rate changes: dropping to 80% after parental leave, returning to full time in September, a temporary arrangement. The formula then applies period by period, not to the whole year.
Example: full time from January to June, then 80% from July to December.
- First half: 34 × 1.00 × 6/12 = 17 days
- Second half: 34 × 0.80 × 6/12 = 13.6 days
- Annual ceiling: about 30 days
Adding the periods is more accurate than applying an average rate — and, more importantly, it reflects the actual contract, which is exactly what an audit checks.
Three calculation traps
1. Confusing telework days with working days
Proration reduces the ceiling, not the number of days you are likely to consume. A half-time employee who teleworks on every working day hits a 17-day ceiling in eight or nine weeks.
2. Forgetting that business trips share the same quota
The prorated ceiling covers all days worked outside Luxembourg: telework, assignments, training. With 6 days available, a two-day seminar abroad eats a third of the annual quota.
3. Thinking in rolling years
The threshold is assessed per calendar year. A breach recorded in December is not "made up for" in January: it produces its effects on the year that has closed, and the counter restarts at zero for the new one.
Keeping a margin — and knowing which one
Good practice is to set an alert before the ceiling, proportional to it rather than to a fixed number:
| Ceiling | Suggested alert | Remaining margin |
|---|---|---|
| 34 | 28 | 6 days to absorb the unexpected |
| 27 | 22 | 5 days |
| 17 | 13 | 4 days |
| 6 | 4 | 2 days — one assignment left |
The unexpected is not theoretical: a rail strike, a sick child, a closed road. Those are the days that tip a counter kept too tight.
Your threshold, not the generic one
The app takes your occupation rate and contract period to compute your real ceiling, then warns you before the edge — not after.
See the appFrequently asked questions
Is the 34-day threshold reduced for part-time work?
Yes. The threshold is prorated according to the occupation rate. An employee at 50% across a full year has roughly 17 days, not 34.
How is the threshold calculated for a mid-year hire?
The threshold is reduced in proportion to the contract's duration within the calendar year. A full-time employee starting on 1 July has roughly 17 days for the second half.
What is the proration formula?
Personal threshold = 34 × occupation rate × (months covered by the contract ÷ 12). An employee at 75% starting on 1 October gets 34 × 0.75 × 3/12 = 6.375, i.e. 6 days in the example used by the Luxembourg administration.
Does the counter reset every year?
Yes, the threshold is assessed per calendar year. Exceeding it in December does not eat into the following year's quota, but it produces its effects on the year that has closed.
Does a change of working time mid-year complicate the calculation?
Yes. The threshold has to be calculated per homogeneous period and then added up. Moving from 100% to 80% on 1 July gives a ceiling made of the two half-years calculated separately.
Does proration apply to the social security threshold too?
The social side reasons in percentage of working time, which already builds part-time work in. See the two thresholds of cross-border telework.
Sources
- Le Quotidien — Luxembourg clarifies the 34-day rule (the 75%-from-1-October example).
- Frontaliers Grand Est — The 34-day rule — proration.
The calculations shown are indicative and meant to illustrate the proration principle. The rounding method and the treatment of particular periods are matters for the competent authority and for a professional review of your situation.