How are the CO2 emissions of a car calculated if I did not enter a license plate?

If you do not enter your license plate, we use standard emissions factors for the selected vehicle type and fuel type. We collect these values from the website co2emissiefactoren.nl, which shows scientifically supported information on the CO₂ emissions of several types of vehicles. Here, we collect an average value for each vehicle-fuel type combination.

For hybrid cars, a value is also given, but since the ratio between driving electric and on fuel is often unknown, these values are less accurate than those of other cars.