MilometryBelgium's kilometre allowance moves every quarter, and in 2026 it moved every month
From 1 October 2026 the Belgian federal allowance is 0.4452 euro a kilometre. Two systems run side by side, and the date of a journey decides what it is worth.
General information, not advice. Written as general information and correct as far as we know on 5 October 2026. Tax rules change, and how they apply depends on your own circumstances. This is not tax, legal or financial advice: check with an accountant, a tax adviser or HMRC before you rely on it.
From 1 October to 31 December 2026, the Belgian federal kilometre allowance is 0.4452 euro a kilometre. It was set by circular 771 of 16 September 2026 and published in the Moniteur belge on 29 September. The quarter before, it was 0.4440.
A rise of 0.12 of a cent is not news on its own. What makes Belgium worth understanding is that almost no other system covered here changes its figure this often, and that two different figures are legitimately in use at the same time.
Two systems, side by side
Belgium has run two ways of setting the allowance since October 2022.
The quarterly system. FOD BOSA, the federal civil service department, recalculates the amount every three months against fuel prices and publishes it by circular. This is the figure federal staff are paid for service journeys in their own car, and the one that changed on 1 October. BOSA introduced the quarterly revision in 2022 to react faster to fuel prices than the old arrangement allowed.
The annual system. A single figure for twelve months from 1 July. For 1 July 2026 to 30 June 2027 it is 0.4761 euro a kilometre.
Private employers can reimburse at either. The national social security office, the ONSS, accepts both as a fair reimbursement of the employee's costs rather than as pay, which means no social contributions on it, provided the car is not owned or financed by the employer. The ONSS also treats the figure as all inclusive: fuel, insurance and maintenance are covered by it, not claimed on top.
There is one catch. An employer who chooses the annual figure has to keep it for the whole twelve months, and can return to the quarterly one on 1 July 2027 at the earliest. It is a choice made once a year, not a quarter by quarter comparison of which figure happens to be higher.
2026, the year it moved monthly
The quarterly mechanism follows fuel prices, and the spring of 2026 showed what that means in practice. Instead of one figure for April to June, BOSA published one per month, each set after the event and applied backwards:
| Period | Euro per km | Circular |
|---|---|---|
| 1 January to 31 March 2026 | 0.4326 | 762 |
| April 2026 | 0.4571 | 765 |
| May 2026 | 0.4841 | 766 |
| June 2026 | 0.5055 | 770 |
| 1 July to 30 September 2026 | 0.4440 | 768 |
| 1 October to 31 December 2026 | 0.4452 | 771 |
Between March and June the figure rose by more than 7 cents a kilometre, then fell back by more than 6 in July. A driver doing 1,500 business kilometres a month would have seen the same work valued at about 649 euro in March and about 758 euro in June.
Why the date of the journey matters
In most systems, the date of a business journey only decides which tax year it belongs to. In Belgium it decides the rate.
A trip on 30 September 2026 is worth 0.4440 a kilometre under the quarterly system. The same trip on 1 October is worth 0.4452. A trip in June is worth 0.5055, a figure that was not published until July. So an employer settling expenses at the end of a month, or catching up on a backlog, needs to know when each journey happened, not just how far it went.
That is the argument for a dated, journey by journey record, and it is stronger in Belgium than almost anywhere. A monthly total of kilometres is enough to apply a flat rate. It is not enough to apply a rate that changes underneath it.
How it compares with the UK
At about 85p to the euro, 0.4452 euro a kilometre is roughly 61p a mile. Britain's approved rate is 55p a mile for the first 10,000 business miles in the tax year and 25p after that, for journeys from 6 April 2026.
| Belgium (quarterly) | UK | |
|---|---|---|
| Rate | 0.4452 euro per km (1 October to 31 December 2026) | 55p per mile, then 25p (from 6 April 2026) |
| How often it changes | Every quarter, sometimes monthly | Rarely: 45p held from 2011 to 2026 |
| Threshold | None | 10,000 miles |
| Alternative figure | Annual, 0.4761 euro per km to 30 June 2027 | None |
| Who sets it | FOD BOSA, by circular | HMRC |
The two systems sit at opposite ends. Britain held one figure for fourteen years and pays it on a band. Belgium recalculates against the pump and pays it flat. Neither is wrong, but a Belgian figure quoted from memory is very likely to be out of date.
Milometry has a Belgian scheme built in, and because it dates every journey, the quarter each kilometre fell in is part of the record.
Sources
- Vergoeding voor reiskosten (BOSA), the full table of amounts with the circular for each
- Omzendbrief nr. 771 van 16 september 2026 (BOSA)
- Omzendbrief nr. 768 van 29 juni 2026 (BOSA)
- Indemnité kilométrique: augmentation et révision trimestrielle (BOSA, 2022)
- Instructions administratives ONSS: remboursement de frais propres à l'employeur
- Increasing mileage rates (HMRC policy paper), for the British comparison
General information for drivers in Belgium and the UK, not legal or tax advice. The Belgian figure changes every quarter: check the current amount with FOD BOSA, and which system your employer uses.
