Length of trek and length of walking day.
	Average altitude and altitude gain and loss.
	Trail conditions.
	Level of porterage or backpacking.
	Temperature range and likely weather conditions.
	Remoteness to services and general level of comfort.

A (Easy): Experience is not necessary at this level: anyone who is in good health and fit enough to enjoy a good weekend hill walk can manage an A grade. Usually, A grade treks are short in duration and at lower altitudes; often they are optional, giving a chance of a rest day. However, walking always involves some exertion: trails are seldom flat, and you must still expect to have a reasonable amount of ascent and descent. You would normally walk for 4 to 5 hours during the day.
Typical holidays at this grade:

	Trekking from Neor To Subatan.
	Trekking from Kevir to Caspian sea

B (Moderate): Most people who enjoy a weekend in the hills or mountains at home are capable of undertaking a trek at this level: you need to be in good health and reasonably fit, and you will almost certainly be taking regular exercise. A trek could be graded B either as a fairly easy medium-duration walk, or as a harder, shorter walk. Some walking at higher altitude and the occasional longer or more difficult day may be involved, but generally conditions underfoot will be fair. A walking day would normally be between 5 to 8 hours long and no experience is necessary.
Typical holidays at this grade:

	Classic Mt.Zagrous Trail
	Gahar Lake

C (Strenuous): For any trek at this level, fitness is most important and you may have to improve yours before departure. Most C grade treks are equivalent to extended walking in mountainous terrain at home, but usually at significantly higher altitudes; climate and remoteness can also play a part. Walking days are usually between 6 to 8 hours although there may be some longer days for pass-crossing or similar. Previous trekking experience is desirable but not essential if you are confident of your physical condition.
Typical holidays at this grade:

	Alamoot
	Mt.Zagrous trekking

D (Tough): At this level we recommend previous experience of trekking, preferably at altitude, and you need complete confidence in your physical condition and your ability to trek for many days without a break and be able to cope with difficult underfoot terrain such as scree, snow or difficult paths on steep mountainsides. Extremes of altitude and weather may also be encountered, and on some treks it may be necessary to use ice axe and crampons. Stamina is very important, as walking days can be from 6 to 9 hours or even longer on pass-crossing days.
Typical holidays at this grade:

	Climbing Mt.Sabalan (C/D Grade)
	Damavand Ascend (C/D Grade)

E (Very Tough): To earn an E grade, a trek is likely to involve all the elements of a D grade plus extra factors of significant difficulty - tricky river crossings, very high or difficult passes, glaciers, or trekking peaks where basic climbing skills may be required. Often some special equipment such as ice axe and crampons will be needed and if so we require you to have experience of them. While normally walking for 7 to 9 hours a day, you should be prepared for up to 11 hours, or on some climbs even longer.
Typical holidays at this grade:

Alamkouh Ascend