Continuing to work while receiving Social Security benefits may cause the benefit to be reduced below the anticipated amount. If you are under the full retirement age (currently 66), an earnings test determines whether your Social Security retirement benefits will be reduced because you earned more from a job or business than an annual exempt amount.
As a general rule, the earnings test is based on income earned during the year as a whole, without regard to the amount you earned each month. However, in the first year, benefits you receive are not reduced for any month in which you earn less than one-twelfth of the annual exempt amount.
For 2015, Social Security beneficiaries under the full benefit retirement age who have earnings in excess of the annual exempt amount are subject to a $1 reduction in benefits for each $2 earned over the exempt amount ($15,720 in 2015) for each year before the year during which they reach the full benefit retirement age. However, in the year beneficiaries reach their full benefit retirement age, earnings above a different annual exempt amount ($41,880 in 2015) are subject to a $1 reduction in benefits for each $3 earned over the exempt amount. Social Security benefits are not affected by earned income beginning with the month the beneficiary reaches full benefit retirement age.