Weight matters twice on a Nepal trek: on small mountain aircraft, and on the back of the porter who carries your bag.
Quick answer: Flights to Lukla and other mountain airstrips allow about 15 kg per passenger: 10 kg checked in a soft duffel plus 5 kg hand luggage. Extra weight is charged per kilo and may not fly at all. One porter usually carries for two trekkers. The International Porter Protection Group (IPPG) sets 30 kg as the maximum load, so aim for about 10–12 kg each.
Pack in a duffel, not a suitcase
Use a soft, strong duffel bag (many companies, including us, provide one). Porters tie bags together and carry them with a head strap. Hard cases won't work.
Leave the rest in Kathmandu
Hotels in Kathmandu store luggage for free while you trek. Leave city clothes, laptops and souvenirs there.
Porter welfare
Porters are the backbone of trekking in Nepal. Good companies limit loads, provide proper clothing and insurance, and make sure porters have shelter and food. See a day in the life of a porter and guide.
Weigh before you fly
Weigh your duffel at the hotel the night before. The heaviest items are usually sleeping bags, down jackets and too many clothes. Wear your boots and heaviest layers on the flight.
See Lukla flight guide, domestic flights and daypack checklist.