There are variations in the level of difficulties and altitudes in Nepal. Based on the region and trips, the trip grade can be divided into five different categories. Basically, it applies in trekking, peak climbing, and expedition.
Easy or Grade A (*)
The easy grade is you do not find any difficulties to trek. The trip reaches up to 3000 meters altitude. The trails will not be rugged and these types of treks are highly suitable for family trips. The trips are generally around of 1 week.
Moderate or Grade B (**)
Moderate or Grade B trips include 1 week to 15 days itinerary. It can reach up to 5000 meters altitude range, but the trails will be moderate (nor easy, nor tough). High altitude may matter on walking speed and distance. You need to have acclimatization over 3000 meters.
Strenuous or Grade C (***)
Strenuous trekking grade is both moderate and difficult. Even in this grade, treks reach around 5000-5500 meters. You walk generally 6-7 hours every day. Strenuous treks require good physical condition and acclimatization. if some problems appear, you have to walk down and take some hot drinks or soup. You may get affected fast if you have high blood pressure, asthma, heart disease or complicated medical conditions.