Four calculators for the typical car-cost questions
A car costs much more than its sticker price. To compare models, drivetrains or usage patterns properly, you need separate views on energy cost, tax and financing. That is what these four dedicated calculators provide:
| Calculator | Typical question |
|---|---|
| Fuel-cost calculator | What does a given trip or a month of commuting cost? |
| kWh cost calculator | What do charging or household electricity costs add up to? |
| Motor vehicle tax calculator | What annual tax does my vehicle carry? |
| Car loan calculator | What monthly rate goes with which term and interest rate? |
Fuel costs: distance, consumption, price
The base formula is trivial:
- Fuel cost = distance ÷ 100 × consumption × price per litre
For a distance of 180 km, consumption of 6.8 l/100 km and a price of 1.82 € per litre, this comes to about 22.28 €. Driving the same distance both ways doubles the cost – under-estimating consumption builds a systematic shortfall into the calculation. Realistic numbers do not come from a sales brochure but from the trip computer of your last 5,000 kilometres.
Important real-world drivers of consumption:
- Motorway speed (consumption rises roughly quadratically with speed)
- Short trips below 5 km (engine never reaches operating temperature)
- City driving with traffic lights and stop-and-go
- Payload, roof racks, towing
- Winter operation with cold engine, heater and friction losses
- Aggressive driving with high engine speeds
Someone who drives 6.8 l/100 km in summer can easily reach 8.5 or 9 l/100 km in winter. The fuel-cost calculator is therefore best used with two scenarios (summer and winter) to estimate yearly cost realistically.
Electricity costs and EV charging
The logic for electricity consumption is just as simple, only the unit is kilowatt-hours instead of litres:
- Electricity cost = consumption in kWh × price per kWh
For an EV consumption of 18 kWh/100 km and a home-charging price of 0.34 €/kWh, a 180 km trip costs about 11 €. If the same vehicle charges at a public fast charger for 0.68 €/kWh, the cost is 22 € – roughly double. Anyone using their own wallbox in everyday life therefore drives significantly more cheaply than someone who relies solely on public charging.
Typical price bands in spring 2026:
| Type of charging | Price per kWh |
|---|---|
| Household electricity, private | approx. 0.29 to 0.38 € |
| Wallbox with special tariff / PV self-consumption | approx. 0.10 to 0.30 € |
| Public AC charger | approx. 0.45 to 0.65 € |
| Public DC fast charger | approx. 0.60 to 0.90 € |
EV range depends noticeably on temperature. At -5 °C, a range of 400 km in spring quickly drops to 280–320 km. The kWh cost calculator is therefore useful not only for EVs but also for household electricity – lighting, large appliances, heat pumps, wallbox self-consumption.
Motor vehicle tax: displacement, CO₂ and special cases
For combustion-engine cars, the German motor vehicle tax has been calculated by displacement and CO₂ since 2009:
- Displacement component: 2.00 € per 100 cc for petrol, 9.50 € per 100 cc for diesel
- CO₂ component: free up to 95 g/km, above that staggered rates of 1.80 € to 4.00 € per g/km depending on the band
A worked example for a 1,500 cc petrol car with 138 g/km CO₂:
| Component | Calculation | amount |
|---|---|---|
| Displacement base | 1,500 ÷ 100 × 2.00 € | 30.00 € |
| CO₂ tier 1 (96–115 g/km) | 20 × 2.00 € | 40.00 € |
| CO₂ tier 2 (116–135 g/km) | 20 × 2.20 € | 44.00 € |
| CO₂ tier 3 (136–155 g/km) | 3 × 2.50 € | 7.50 € |
| Annual tax | 121.50 € |
Diesel and hybrid vehicles follow the same scheme with different base rates. Pure electric vehicles are exempt under Section 3d KraftStG until the end of 2030; after that a half rate based on permissible total mass applies initially. The motor vehicle tax calculator covers the current bands as well as the most important special cases.
Car loan: annuity, balloon payment, residual value
A car loan typically combines a down payment, monthly instalments and – for balloon loans and leasing – a large final payment. The classic annuity loan resolves the monthly instalment analytically:
- Instalment = principal × (i × (1 + i)^n) ÷ ((1 + i)^n − 1)
with i = monthly interest rate, n = number of months. For a 25,000 € loan at an effective annual rate of 6.5 % over 60 months, the monthly instalment comes to about 489 €. The interest and principal shares shift over the term – in the first months you pay more interest than principal, at the end the opposite.
Balloon loans have lower monthly payments because a large part of the principal accumulates into a final balloon payment. This form only pays off if you can pay the balloon at term end, refinance it, or sell the car for at least the balloon amount.
Leasing pays not for ownership but for usage. Key metrics:
- Lease factor (monthly payment ÷ list price × 100; lower is better)
- Excess mileage charge above the agreed annual mileage
- Reimbursement for under-mileage
- Return conditions for damage and wear
The car loan calculator shows instalment, interest share and total cost transparently for a classic annuity loan. To evaluate a leasing offer, you should add up the total of down payment, all instalments and the balloon payment, and compare that to the purchase price.
Total cost of ownership: what really costs per kilometre
An honest cost calculation includes more than fuel and tax:
| Cost block | Order of magnitude per year (mid-class) |
|---|---|
| Depreciation | 8 to 15 % of new price |
| Fuel or electricity | depends on annual mileage |
| Insurance (liability + comprehensive) | 600 to 1,500 € |
| Maintenance and repairs | 600 to 1,200 € |
| Motor vehicle tax | 50 to 350 € |
| Tyres | 200 to 500 € |
| Mandatory inspection (TÜV/HU) | approx. 130 € every two years |
| Parking / garage | 0 to 1,800 € |
For a 30,000 € new car driving 15,000 km per year and worth 60 % after three years, depreciation alone is around 4,000 € per year. Per kilometre, this adds up – without tyres and without workshop costs – to 35 to 50 cents, a figure that puts many commuting calculations into perspective.
Common errors in car-cost calculations
- Using manufacturer figures for consumption: WLTP values are a standardised comparison metric, not a promise.
- Ignoring depreciation: for new cars, it is the single largest cost block.
- Forgetting insurance: no-claims class, vehicle type class and regional class can account for a third of annual cost.
- Comparing lease instalments with loan instalments: leasing does not build ownership.
- Dismissing charging costs as "cheap": for pure fast-charger users, electricity is no advantage over an efficient diesel.
Conclusion
Fuel, electricity, motor vehicle tax and loan payments are building blocks. A realistic picture emerges only when they are combined with insurance, maintenance and depreciation and translated into a per-kilometre cost. With the four calculators on Ultra-Rechner, the most important of these blocks can be estimated quickly and honestly.
Sources
- German Motor Vehicle Tax Act (KraftStG) – gesetze-im-internet.de/kraftstg
- Federal Motor Transport Authority – Kfz-Steuer and consumption statistics – kba.de
- ADAC – mobility cost analyses – adac.de
- Federal Network Agency – electricity prices and tariff overview – bundesnetzagentur.de