Investigators on Tuesday confirmed that one of the Iraqis drowned.
Army First Lieutenant Jack Saville also must forfeit $2000 of his military salary per month for six months, military judge Colonel Theodore Dixon ruled.
The 25-year-old West Point graduate could have been sentenced to nine years in prison. He pleaded guilty on Monday to assault and other crimes in one incident, and was convicted on Tuesday of an assault charge in a second case.
Reading from a statement during the sentencing phase of his trial, Saville apologised and said: "I desperately wish to remain in the army. It has given me more than I could ever imagine."
He will be allowed to remain in the army.