Your initial grace period begins on the first day of the month nearest to the day you leave school or drop below half-time status.  Your grace period ends 9-months after attendance and 6-months following a deferment (for 1st time borrowers after 7/1/1987).  Interest begins to accrue on that grace-ending date, not the date on which your first payment is due.  To repay your loan without interest charges, you must pay it in its entirety prior to the end of the grace period.