Most businesses pay their employees on a weekly, biweekly or semi-monthly basis. Each pay period is calculated differently. However, calculating semi-monthly pay is not as straightforward as calculating weekly or a biweekly payrolls. With the latter two, the employee is paid every week or every other week, respectively. A semi-monthly payroll means that he gets paid twice per month, usually on the 15th and the last day of the month. An hourly semi-monthly employee’s pay may fluctuate each pay period but a salaried employee’s tends to stay the same.

Accumulated Hours

Determine the number of hours worked within the semi-monthly pay period. Hourly workers are paid according to hours worked. To allow enough time for payroll processing, your semi-monthly pay period may include hours worked up to a certain point, before the actual pay date. Check with your employer or your payroll department for the start and end date of the pay period to know the precise time frame for which you will be paid. Then, tally your hours worked within this time frame.

Calculate and Divide

Multiply hours worked by your hourly rate. For instance, if you worked 70 regular hours during the semi-monthly pay period and earned $10 per hour, you would calculate as follows: 70 hours x $10 = $700, your gross semi-monthly pay.

Salaried Formula 

Use the salaried formula if you are a salaried employee. Generally, salaried workers are paid a set wage each pay period; it only changes if the employee has had a pay increase/adjustment or a deduction change.

Unlike hourly semi-monthly employees, salaried workers are paid current; up to the actual pay date. The calendar year has 2080 hours (40 hours x 52 weeks), which includes paid time off, such as vacation and holidays. A semi-monthly payroll has 24 pay periods in the year. For example, say your annual salary is $50,000. Calculate as follows: $50,000/24 pay periods = $2,083.33, your gross semi-monthly pay.

Net Pay

Subtract your deductions from your gross pay to arrive at your net pay. Deductions include statutory withholding, such as taxes and garnishments, and voluntary deductions, such as retirement or 401(k) plan contributions and insurance premiums for medical, dental and vision plans.


If the semi-monthly payday falls on a weekend or holiday, most employers pay their employees on the preceding business day. Some employers have printed payroll calendars, which they distribute to employees to keep them abreast of semi-monthly time sheet due dates and pay dates.