There are variations in the level of difficulties and altitudes in Nepal. A trip grade can be divided into five categories based on the region and trips. It applies to trekking, peak climbing, and expedition.
The easy grade is if you do not find any difficulties in trekking. The trip reaches up to 3000 meters altitude. The trails will not be rugged, and these treks are highly suitable for family trips. The trips are generally around one week.
Moderate or Grade B trips include one week to 15 days itinerary. It can reach up to 5000 meters altitude range, but the trails will be intermediate (neither easy nor challenging). High altitude may matter on walking speed and distance. You need to have acclimatization over 3000 meters.
The strenuous trekking grade is both moderate and difficult. Even in this grade, treks reach around 5000-5500 meters. You generally walk 6-7 hours every day. Strenuous hikes require good physical condition and acclimatization. If problems appear, you have to walk down and take hot drinks or soup. You may get affected fast if you have high blood pressure, asthma, heart disease, or complicated medical conditions.
Very strenuous trekking covers 4000 meters to 6000 meters. No doubt, your physical fitness, and acclimatization are essential. It is said that generally, you walk about 7 hrs every day, but the altitude becomes an obstacle, and it is tough to walk that much. You have to cross the Himalayan passes using essential climbing equipment. Even the trail is steep and slippery.
Technical Challenging Trekking grade is for those who love to do highly adventurous treks/trips. Its elevation reaches up to 6000 meters and consists 15-25 days itinerary. It is not less than peak climbing.