Mobility budget becomes mandatory in 2027: what your company must prepare now

More than 85% of the companies that will be required to offer a mobility budget in 2027 have not yet started preparing. That is the finding of a study by Acerta. Employers with 50 or more employees must be ready by 31 December 2026 at the latest.

The federal government approved a preliminary bill on 9 January 2026 that frames this obligation. The mobility budget has existed on a voluntary basis since 2019. It is now set to become a legal obligation for a large share of Belgian employers. The question is no longer whether you need to introduce it, but how to do it correctly.

In this article, you will find a concrete answer to three questions:

1. Is your company affected?
2. How does the mobility budget work in practice?
3. What should you arrange now?

Is your company affected? The two conditions to check

Not every company falls under the new rules. Two cumulative conditions apply.

Condition 1: company size determines the deadline

The threshold applies to the entire workforce — not only to employees with a company car.

If you are above the threshold, the next step is turning those dates into a work plan. Our RewardFlex mobility budget solution sets out what the employer has to put in place, pillar by pillar.

Condition 2: company cars provided for more than 36 months

You must have offered company cars for more than 36 months. That period may have been interrupted. If you have only recently built a car fleet, you are not yet affected until those 36 months are reached.

One more point: you are not required to open the switch overnight for every employee. Where a leasing contract is still running, the employer may wait for it to expire before allowing the move to the mobility budget. This is common practice and is usually written explicitly into the mobility budget policy: the employee submits the request, and it takes effect at the end of the lease on their current car.

Is the mobility budget mandatory for companies with fewer than 50 employees?

Yes, but later — and not for all of them. Employers with 15 to 49 employees follow a year behind: they have until 31 December 2027. Below 15 employees the exemption is permanent, with no deferred deadline to follow.

A concrete example: a company with 80 employees and a five-year-old fleet must offer the mobility budget by 31 December 2026 at the latest. A company with 35 employees and a four-year-old fleet has until 31 December 2027.

Unsure where you stand?

Important: employees remain free to keep their company car. The obligation lies with the employer to offer the choice — not with the employee to accept it.

What employees can do with their budget: the three pillars

The mandatory mobility budget is structured around three pillars. Your latitude is not the same across all three: one pillar is optional, one is mandatory, one applies automatically. Your employees then choose how to use their budget within that framework.

Pillar 1 — a zero-emission company car

Optional for the employer. You are free to decide whether to activate it. Employees swap their current car for a fully emission-free vehicle. Since 1 January 2026, only zero-emission vehicles are eligible for pillar 1. Any remaining budget flows to pillar 2 or pillar 3.

Pillar 2 — sustainable mobility (the most tax-efficient)

Mandatory to offer. This is the only pillar you are legally required to open, and it is also the most attractive one: budget allocated to pillar 2 is exempt from withholding tax (bedrijfsvoorheffing / précompte professionnel) and from RSZ/ONSS social security contributions. Eligible spending includes:

• public transport subscriptions
• shared mobility (car, bike, scooter)
• purchase or leasing of a bike (electric or classic)
• housing costs close to the place of work

Pillar 3 — the balance in cash

Automatic. There is nothing to activate: if the employee does not use the full budget through pillars 1 and 2, the balance is paid out in cash. A special employee contribution of 38.07% applies. This is the least tax-efficient outcome — but it is not chosen, it is simply what remains.

How to calculate the right amount: the TCO method in three steps

The mobility budget is based on the Total Cost of Ownership (TCO) of the company car the employee gives up. This total cost includes leasing or purchase, maintenance, insurance, fuel and taxes.

The calculation runs in three steps:

1. determine the annual TCO of the company car for each affected employee
2. check the legal limits that apply — minimum, maximum and the ceiling relative to gross salary (see below)
3. set the individual budget for each employee based on steps 1 and 2

What is the maximum amount of the mobility budget?

The mobility budget sits between two limits. For 2026, the annual budget must be at least €3,233 and at most €17,244. On top of that comes a relative ceiling: the budget may not exceed one-fifth of the employee’s total annual gross salary.

Two points to watch:

• the amounts are indexed every year
• for an employee who recently joined a car plan, the budget can be granted pro rata

No two employees automatically receive the same budget. TCO varies from one car to the next. A rigorous calculation avoids later payment errors.

It is exactly this work — recalculating each TCO, applying the ceilings, tracking individual budgets over time — that becomes unmanageable in a spreadsheet beyond a few dozen cars. RewardFlex calculates and steers individual mobility budgets from your car policy.

Is this going to cost me more?

This is the first question raised in the management committee, and in the vast majority of cases the answer is no.

The mobility budget is not an additional envelope. It is calculated on the TCO of a car you are already financing: the leasing, fuel, insurance, maintenance and taxes you pay today for that vehicle. An employee who switches to the mobility budget does not add a line to your payroll — they redirect the one that already exists.

What changes is the allocation, not the amount. Part of the envelope leaves the fleet line to fund a bike, a train subscription or housing costs close to work. And because pillar 2 is exempt from withholding tax and from RSZ/ONSS contributions, the redirected euro goes further there than it does in a car.

The real costs sit elsewhere: implementation time, legal support on the car policy, and the management tool. These are one-off project costs, unrelated to the size of the budgets distributed.

5 steps to be ready by 31 December 2026

Starting now means building a solid foundation and avoiding last-minute decisions.

1. check your scope — count the total workforce and assess how long you have been offering company cars
2. map your car fleet — which employees have a company car, what is the TCO per car, when do the leasing contracts expire? This is the moment to pull out your car policy, which is the calculation basis for the mobility budget
3. calculate individual budgets — based on TCO per employee and the applicable legal limits
4. choose a management platform — it simplifies administration, from budget tracking to reimbursements in pillar 2. If you run several benefit plans side by side, RewardPilot centralises steering and administration in a single interface
5. communicate early — explain the options available, give concrete examples per pillar and leave enough time for questions

Practical advice: do not wait for current leasing contracts to expire before starting to prepare.

Start now, avoid the rush

The mobility budget is set to become a fixed part of the salary package in thousands of Belgian companies. Employers with 50 or more employees must be ready by 31 December 2026 at the latest — and the vast majority is not. Starting now means turning a legal obligation into a real benefit for your employees.

Do you advise employers rather than being one? Our article for accountants, payroll agencies and advisers sets out the questions to ask a client and the order in which to prepare their case.

We gathered the questions HR professionals asked during our webinar in a dedicated article: mobility budget, the most frequently asked questions. These are the six that come back most often.