In payroll, semi-monthly meaning is a pay period in which employees receive compensation twice a month usually on the 1st and 15th or 15th and the last day. This translates to 24 payments a year. It is contrasted with biweekly pay, which is received every 14 days, resulting in 26 payments per annum. Semi-monthly pay periods are not even in number of days that they represent, i.e. one pay period can represent more days than the other. With this schedule, employers have to make sure that the payroll is computed correctly even though the number of workdays differs.