Conscription in Iran

According to Constitution of the Islamic Republic of Iran all men older than 18 years old must go for military service or conscription ( read "Sarbâzi"). Length of conscription is not a fixed time according to the law, it can change due to country's need to soldiers but couldn't exceed 2 years. Minimum time is 18 months.

History
In June 1925, Reza Shah approved conscription law at National Consultative Majlis. At that time every male person who had reached 21 years old must serve for military for 2 years. However, as country needed 100,000 person and qualified population was 1,000,000 they announced just one man between every 10 men must serve for military.

Conscription time
Conscription time is shown in months in each year:

Female Conscription
Before the 1979 Iranian Revolution, both men and women were conscripted. Post-revolution, the law changed and women were no longer subject to conscription. However, some continue to serve as volunteers.