Privates will get five years to move up or move out. Specialists and corporals will have an eight-year pull date and three-stripe sergeants will have 14 years.
The move narrows the promotion windows for career-minded soldiers as the Army works to trim 80,000 troops from its ranks by 2018.
The first rank that will allow a soldier to reach the 20-year retirement mark is staff sergeant. To reach the 30-year retirement, which brings 75 percent of base pay, soldiers must have achieved the rank of sergeant major, or be on a promotion list for the top enlisted rank.
The promotion timelines, released in a Pentagon memo, apply to the regular Army, Army reserve and National Guard.
The lowest ranks are seeing the biggest change from the new policy. Under the old rules, specialists could stay in the Army for 12 years before they were forces to gain rank or leave.