Starting August 9, 2018, USCIS officers must follow a new policy to calculate unlawful presence for F, J, and M status holders and their dependents who are admitted in duration of status or until a specific date. The policy for those in other nonimmigrant statuses will remain the same.
This policy is important because a student may be subject to a 3-year, 10-year, or permanent bar to admission if they accrue too many days of unlawful status.