BMW X1 sDrive18i (€41,000, 143 g), fuel card, SME
Corporate income tax due on the disallowed expense
€360/year
- Annual benefit in kind of the driver
- €4,498.00
- Disallowed expense rate
- 40%
- Disallowed expense added to the taxable base
- €1,799/year
Free calculator · Company car · 2026
Disallowed expenses (DNA) on the benefit in kind calculator
When a company provides a car, part of the benefit in kind is added back to its taxable profit: 17%, or 40% if it also covers the fuel. The calculator quantifies the disallowed expense and the corresponding corporate income tax.
Your parameters
Examples:
€
g/km
months
Fuel card, charger at the office or reimbursement of charging: the disallowed expense rises from 17% to 40% of the benefit in kind.
Reduced rate on the first €100,000 of profit for SMEs; otherwise 25%.
Result
Corporate income tax due on the disallowed expense
€324/year
- Annual benefit in kind of the driver
- €4,050.00
- Disallowed expense rate
- 40%
- Disallowed expense added to the taxable base
- €1,620/year
- Corporate income tax rate
- 20%
The four possible cases
| Fuel paid by the company | SME rate | Annual corporate tax on the disallowed expense |
|---|---|---|
| Yes | Yes | €324 |
| Yes | No | €405 |
| No | Yes | €138 |
| No | No | €172 |
Calculate the true cost of this company car
The full calculation adds up every tax item for the company and the director’s tax for this car.
Worked examples 2026
Calculated by the same engine as the full true cost calculation, never estimated by an AI.
Same X1 without fuel card, corporate tax 25%
Corporate income tax due on the disallowed expense
€191/year
- Annual benefit in kind of the driver
- €4,498.00
- Disallowed expense rate
- 17%
- Disallowed expense added to the taxable base
- €765/year
Skoda Enyaq 85 (€58,180, electric), charging paid, SME
Corporate income tax due on the disallowed expense
€160/year
- Annual benefit in kind of the driver
- €1,995.00
- Disallowed expense rate
- 40%
- Disallowed expense added to the taxable base
- €798/year
How it is calculated
Disallowed expense = benefit in kind × 17% (40% if the company also covers fuel / electricity) True cost = disallowed expense × corporate income tax rate (20% SME or 25%)
Article 198, § 1, 9° of the Income Tax Code (CIR 92) requires the company to add back to its taxable base 17% of the benefit in kind of each car it provides. This rate rises to 40% when the company bears, in whole or in part, the fuel or electricity costs linked to private use (art. 198, § 1, 9°bis).
The disallowed expense is not a cash outflow: it is an amount on which the company pays corporate income tax. Its true cost is therefore the disallowed expense multiplied by the corporate tax rate, 20% for an SME on the first bracket of profit, 25% otherwise. A loss-making company does not pay it immediately, but the disallowed expense reduces its carried-forward losses.
The calculator takes the benefit in kind from the benefit in kind sub-engine, then applies these rates, exactly like the “disallowed expenses” line of the Taxation category of the TCO.
Frequently asked questions
When does the disallowed expense rise from 17% to 40%?
As soon as the company bears, even partially, the fuel or electricity costs linked to the private use of the vehicle: fuel card, charger at the office used for private journeys, reimbursement of home charging.
Does a personal contribution from the driver reduce the disallowed expense?
Yes: the disallowed expense is calculated on the benefit in kind after deduction of the personal contribution. If the contribution cancels out the benefit in kind, the disallowed expense disappears.
Does the disallowed expense apply to electric cars?
Yes, on the minimum benefit in kind (€1,690 in 2026) or on the calculated benefit in kind if higher. An electric car therefore generates at least €287 of disallowed expenses at 17%, or €676 at 40% if the company pays for the electricity.
Is the disallowed expense deductible the following year?
No. It is a permanently disallowed expense, added to the taxable profit every year for as long as the car is provided.
Going further
benefit in kind · company
Company car benefit in kind in 2026: formula, reference CO2 and worked examples
The full 2026 company car benefit in kind formula in Belgium: reference CO2, age factor, legal minimum and worked examples for petrol, diesel and electric cars.
6 min read
company · leasing
Company car leasing or buying: which should you choose in 2026?
Finance lease, operating lease or outright purchase through your company: balance sheet, depreciation, VAT and deductibility compared to choose the right financing in 2026.
6 min read