Extended range electric vehicles offer the possibility to generate electrical energy with a setup of combustion engine and generator when the state of charge of the traction battery is low. As a result, the overall range can be extended to familiar values. The dimensioning of the purely electric range, i.e. the possible cruising range without use of the combustion engine, has much influence on the selling price and on the possible amortisation of the higher initial costs with respect to a comparable conventional car. In this paper, driven distances and consumptions of extended range electric vehicles which were measured during a field test are presented and discussed. The vehicles were used by private persons and by companies. A cost analysis is conducted to identify the necessary electric range for an early amortisation.