The current Opel Kadett covers up to 945 km on a full tank, based on combined-cycle consumption. Figures below are the best-range variant in each generation.
| Years | Powertrain | Range |
|---|---|---|
| 1979–1984 | Combustion | 646 |
| 1984–1991 | Combustion | 945 |
Range is calculated from each variant’s fuel tank capacity and combined-cycle consumption (tank ÷ consumption × 100), for the best-range variant in each generation — real-world range varies with driving style and conditions. Figures outside a plausible range for the tank size are excluded.