In general, carry-on baggage may not be larger than the space under the aircraft seat in front of you. However, different airlines have different maximum carry-on dimensions, so be sure to check what is permitted on your flight.
Baggage rules for economy class varies with the airline. Please check with the airline that transports you. If you are traveling with a full-price ticket on a regularly scheduled flight, the maximum weight is usually 30 kg and in economy fare 20 kg.