An incomplete month of work happens when an employee: Starts work after the first day of the month. Resigns from work before the last day of the month. Has a no-pay leave of one or more days within the month. Is on reservist training during the month. The salary proration formula for an incomplete month is: [(Monthly gross rate of pay) / (Total number of working days in that month)] * Total number of days the employee actually worked in that month.