According to lufthansa carry on size dimensions guidelines, an economy class passenger's suitcase may only be up to 55 x 40 x 23 centimetres (or around 21.6 x 15.7 x 9 inches) in size and 8 kilogrammes (17.6 pounds) in weight. The exact rules and any modifications from Lufthansa should always be checked, though, as carry-on weight and size limitations can change based on the ticket class and destination. Following these guidelines makes flying with Lufthansa more convenient and comfortable by guaranteeing that your carry-on luggage fits in the overhead bins or under the seat.