How AutoCalcul calculates

Purchase: price incl. VAT, VAT and the margin scheme

Purchase counts the full outlay at the time of buying. VAT of 21% applies if the vehicle is new or sold by a professional — except under the margin scheme (a used car sold by a professional with VAT on their margin only: nothing is invoiced to the buyer, nothing is recoverable).

VAT applicable  = (new OR professional seller) AND no margin scheme

Price entered excl. VAT : VAT = price excl. VAT × 21%      ; price incl. VAT = price excl. VAT × (1 + 21%)
Price entered incl. VAT : price excl. VAT = price incl. VAT / (1 + 21%) ; VAT = price incl. VAT − price excl. VAT
No VAT applicable       : price incl. VAT = price excl. VAT = displayed price (no VAT to break out)

Purchase = price incl. VAT

The resolved price excluding VAT then serves as the basis for recoverable VAT, the insurance estimate and the resale value estimate. Depreciation, for its part, applies to the net asset (price incl. VAT − recoverable VAT — see the Tax shield section).

Energy: consumption × price, with compound inflation

The cost per kilometre follows from the consumption per 100 km and the energy price; the first year’s cost is then projected over the duration with compound inflation.

Petrol / diesel : €/km = (consumption L/100 km ÷ 100) × price per litre

Electric        : weighted price €/kWh = home price × % home charging
                                       + public price × (1 − % home charging)
                  €/km = (consumption kWh/100 km ÷ 100) × weighted price

Self-charging hybrid (WLTP consumption ≥ 4 L/100 km) :
                  like a petrol car, €/km = (consumption ÷ 100) × price per litre

Plug-in hybrid (PHEV, WLTP consumption < 4 L/100 km) — built-in assumptions :
                  40% of km on electricity at 17 kWh/100 km,
                  60% of km on fuel at 6.0 L/100 km
                  €/km = fuel share + electric share

Total = Σ over the duration of (year 1 cost × (1 + energy inflation)^i)

Maintenance: per-kilometre costs and roadworthiness test

Four items — mechanical servicing, tyres, cleaning, roadworthiness test — each projected over the duration with general inflation of 2.5%/year (compound).

Servicing = €/km (table above) × km/year, with 2.5%/year inflation
Tyres     = €0.020/km × km/year, with inflation
Cleaning  = €0/km by default (enter it if you wish)
Roadworthiness test : due once the vehicle is 4 years old —
  €48/year in Brussels-Capital, €47/year in Wallonia, €45/year in Flanders

Insurance: estimate by cover level, replaceable

If you do not enter your actual premium, the engine estimates it from the chosen cover and the vehicle’s value (resolved price excl. VAT), then applies general inflation of 2.5%/year.

Taxation: taxes and charges calculated, never guessed

The Taxation category adds up the registration tax (paid once, at registration), the annual road tax × duration, the disallowed expenses on the benefit in kind and the NSSO CO2 solidarity contribution (companies). All the formulas and scales are detailed in the “Belgian taxation in detail” section below.

Taxation = registration tax + road tax × duration + disallowed expenses on BIK + NSSO CO2

The benefit in kind itself is NOT in this total: it is not an outlay for the
company but taxable income for the driver — it is valued at the personal
income tax rate in the director's cost.

Financing: interest actually accrued, leasing surcharge

With cash, the category is zero. With a loan, the engine calculates the monthly instalment (PMT formula) and then the interest actually accrued over the ownership period: if the vehicle is sold before the end of the loan, the balance is repaid and future interest does not accrue.

Financed capital = resolved price excl. VAT − down payment   (floor 0)

Instalment (PMT) = capital × (r/12 × (1 + r/12)^n) / ((1 + r/12)^n − 1)
  with r = annual rate, n = term in months

Interest accrued over m months = instalment × m − capital repaid
  (capital repaid read from the balance of the amortisation schedule,
   m = min(months of ownership, term))

Loan : Financing = interest accrued + arrangement fees

With leasing, the engine isolates the surcharge compared with the capital consumed — the vehicle’s value already being credited through resale.

Months counted = min(term, months of ownership)

Leasing surcharge = monthly rent × months counted
                  + purchase option (financial leasing, only if the
                    contract runs to term)
                  − financed capital × (months counted / term)
                  (floor 0: unrealistic rents do not create a "gain")

Financing = surcharge + arrangement fees

Resale: a credit, from the market value or the used-car valuation

The resale value is never guessed by AI. The engine takes it in a strict order:

1. Your value, if you enter one (trade-in offer, negotiated price…).
2. The RestWaardeBox Belgian market value: for a version identified in the catalogue, the private-sale resale value (incl. VAT) at the age and mileage at the end of ownership. It stays attached to the vehicle as long as the assumptions that produced it (first registration, mileage at purchase, duration, kilometres per year, list price, powertrain) do not change; as soon as you change one of them, it is out of date and the used-car valuation engine takes over until the next query. For a used car with no listing price, the same valuation also provides the purchase price (trade valuation).
3. The used-car valuation engine from AutoCalcul: a deterministic calculation, detailed below, calibrated on the Belgian market. It is also available on its own, free of charge, in the depreciation calculator.

The Detailed report plots the value curve over the whole ownership period: it starts from the purchase price incl. VAT actually paid, follows the half-yearly curve of the market value (or, failing that, the used-car valuation engine year by year) and ends exactly on the resale value used in the total.

The used-car valuation engine, step by step

1. Reference new price. The list price, options included; without a list price, the purchase price excl. VAT is used instead. 2. Base curve. A depreciation rate for each year of the vehicle’s life, the first year including the “driving off the forecourt” loss; part-years count pro rata.

3. Depreciation multipliers. Each annual rate is adjusted for the model’s characteristics — a multiplier below 1 means it holds its value better, and since it applies to every year, the gap widens with age. Body type and gearbox come from the catalogue, the analysed listing or your input; reliability is recognised from a catalogue of engines with a known reputation (for example the 1.2 PureTech). The resulting annual rate is capped between 2% and 40%.

4. Adjustments specific to the individual car. They apply only once, to the value at the resale date: the deviation from normal mileage for the age (more or less sensitive depending on powertrain and reliability), the market’s psychological thresholds and the overall condition. 5. Floor. The value never falls below 6% of the new price or below €500.

6. Anchoring to your purchase price. In the full calculation, the valuation is not used as is: the engine estimates it at purchase (age and mileage on that day) and at the end of ownership, then applies that change to the resolved price excl. VAT. A used car bought below its valuation therefore stays below its valuation at resale; a new vehicle has a purchase valuation equal to its new price. The condition assumed at resale is “good”: the purchase price already reflects the vehicle’s condition at purchase. Each estimate comes with a text explaining the factors that weighed most.

Reference new price = list price (otherwise purchase price excl. VAT)

Value(age, km) = new price × Π over each year of life i : (1 − rate_i)^(share of year i elapsed)
                 × (1 + mileage adjustment) × (1 + km thresholds) × (1 + condition)
  rate_i = base rate(i) × body type × powertrain(age i) × brand × model
           × reliability × price range × gearbox        (capped between 2% and 40%)
  floor  = max(6% of new price, €500)

Resale value     = purchase price excl. VAT × value(end of ownership) / value(purchase)
Resale (credit)  = − resale value used (yours, market value or engine)

Other costs: your fixed annual costs

Parking, breakdown assistance, administrative fees and other fixed costs: each annual amount entered is simply multiplied by the ownership period. By default, everything is set to zero.

Fiscal horsepower (CV)

If the fiscal horsepower is not known, it is estimated from the engine capacity (Art. 23 of the Code of taxes assimilated to income taxes) — note that this is not the power in DIN horsepower. Without an engine capacity (an electric vehicle, for example), the engine uses 7 fiscal hp by default.

Registration tax in Brussels: the power-based scale

Brussels taxes registration according to engine power, read either in fiscal horsepower or in kilowatts: the higher amount of the two is due. The scale has been indexed every 1 July since 2024 — except for vehicles registered by a leasing company, which remain on the non-indexed federal scale. Used vehicles benefit from an age-based reduction.

Registration tax in Wallonia: power, CO2, mass and powertrain

Since 1 July 2025, Wallonia no longer taxes power alone: the registration tax multiplies a base amount (power in kW, decreasing with age) by a CO2 component, a mass component and a powertrain coefficient. The eco-malus has been abolished — CO2 is built directly into the calculation.

TMC = BA × (CO2 / X) × (MAM / 1838) × C

BA  = base amount (power) × age-based reduction, floor of €61.50
X   = 136 under WLTP | 115 under NEDC ; CO2 / X = 1 for an electric vehicle
MAM = maximum authorised mass in kg (box F1 of the registration certificate)
C   = 1 (petrol, diesel, LPG, CNG) | 0.8 (hybrid)
      electric or hydrogen : 0.01 (≤ 120 kW) | 0.10 (≤ 155 kW) | 0.18 (≤ 249 kW) | 0.26 (≥ 250 kW)

Tax due capped between €50.00 and €9,000.00

Registration tax in Flanders: the CO2-based BIV

Flanders calculates its registration tax (BIV) from CO2, the Euro standard and the fuel. Electric vehicles registered before 01/01/2026 are exempt; since then, they pay a flat rate of €61.50. The engine applies the official formula of the Vlaamse Codex Fiscaliteit (art. 2.3.4.1.2 to 2.3.4.1.5), with amounts indexed at 01/07/2026; its results have been checked against the Vlaamse Belastingdienst simulator.

First registered from 2021 onwards (WLTP CO2) :
  BIV = ((CO2 × f × q / 246)^6 × 4,500 + c) × LC
First registered before 2021 (NEDC CO2) :
  BIV = (((CO2 × f + x) / 246)^6 × 4,500 + c) × LC

f   = 1 (petrol, diesel, hybrid)
q   = 1.245 in 2026 (1.07 in 2021, +0.035 per year)
x   = 63.0 g/km in 2026 (+4.5 g/km per year since 2013)
c   = air component by Euro standard (01/07/2026 – 30/06/2027) :
      petrol/hybrid   : Euro 6 €28.54 | Euro 5 €28.54 | Euro 4 €31.76 | Euro 3 €132.31
      diesel          : Euro 6 €628.89 | Euro 5 €636.20 | Euro 4 €646.88 (€636.20 with DPF)
                        Euro 3 €683.30 (€646.88 with DPF)
      unknown standard: derived from the year of first registration
LC  = age correction : < 1 year 100% | 1 year 90% | 2 years 80% | 3 years 70% | 4 years 60% | 5 years 50% | 6 years 40% | 7 years 30% | 8 years 20% | 9 years and + 10%

Amount capped between €58.16 and €14,539.31 (minimum from 30 years)
Electric : €0 if registered before 01/01/2026,
           flat rate of €61.50 from 01/01/2026

Vehicle registered by the lessor: the federal rate

With renting / operating leasing, the vehicle is registered by the leasing company. In Flanders, these vehicles remain under the federal regime (special financing act, art. 4 §3): registration tax on the federal fiscal horsepower scale — without the Flemish electric regime (registration tax of €61.50 for an EV) — and federal road tax (minimum of €107.18/year for an EV, instead of the Flemish regime).

Annual road tax

It is due every year and follows fiscal horsepower (additional surcharges included). Electric vehicles pay the minimum of €107.18/year in Brussels and Wallonia. In Flanders, they are exempt if registered before 01/01/2026, and pay from €69.72/year thereafter (excluding vehicles registered by a lessor).

Benefit in kind (ATN): the driver’s taxable benefit

When a company provides a car, the driver is taxed on a flat-rate benefit. The basis is the new list price incl. VAT (options included, discounts excluded); failing that, the engine approximates it with the purchase price incl. VAT — which underestimates the benefit in kind of a used car.

Age factor (monthly) : −1% per full band of 2 months
                       after month 12, floor 70% — averaged month by month
                       over each year of ownership

Electric : BIK = list price × age factor × 4% × 6/7

Combustion / hybrid :
  % BIK = 5.5% + (CO2 − reference CO2) × 0.1%, capped between 4% and 18%
  BIK   = list price × age factor × % BIK × 6/7

Legal minimum : €1,650/year in 2025, €1,690/year in 2026

“Fake hybrid” (insufficient battery, no combustion equivalent) :
  CO2 used = declared CO2 × 2.5, treated as petrol

Disallowed expenses on the benefit in kind: the company’s share

The benefit in kind is income for the driver, but it also generates a disallowed expense (DNA) for the company: a fraction of the benefit in kind is added to the corporate income tax base. It is this cost — and this cost alone — that appears in the Taxation category.

Disallowed expenses = total BIK × 17%   (40% if the company also pays for fuel)
Company cost        = disallowed expenses × corporate income tax rate (25%, or 20% SME)

The NSSO CO2 solidarity contribution

Monthly employer contribution due for any company car made available to an employee — a self-employed company director is exempt. The engine adds it up year by year, because the multiplier depends on the contribution year.

Petrol / hybrid : [(CO2 × €9) − 768] / 12 × index
Diesel          : [(CO2 × €9) − 600] / 12 × index
Electric        : flat-rate minimum contribution

Multiplier if ordered from 01/07/2023 (depending on the contribution year)
Monthly minimum : €33.22 in 2025, €33.93 in 2026 — raised to €37.33 (2025)
  and €42.34 (2026) if ordered from 01/07/2023 (no multiplier)

Deductibility of car expenses

The deductibility rate depends on the fuel, the CO2 and above all the order date. The engine recalculates it tax year by tax year over the whole ownership period.

Combustion or PHEV ordered between 01/07/2023 and 31/12/2025 — phase-out:

Electric — rate fixed “for life” by the year of order:

Ordered before 01/07/2023 (or date unknown) — classic CO2 table retained:

Special cases: fossil fuel for a PHEV ordered (or first registered) from 2023 is capped at 50% deductibility; a “fake hybrid” is treated with CO2 multiplied by 2.5, like a petrol car.