How earnings affect your benefits
You can continue to work and still get Social Security retirement benefits. Your earnings in (and after) the month you reach your full retirement age will not affect your Social Security benefits. However, your benefits will be reduced if your earnings exceed certain limits for the months before you reach your full retirement age. (The full retirement age is 66 for people born in 1943-1954 and will gradually increase to 67 for people born in 1960 or later.)
If you are younger than full retirement age, $1 in benefits will be deducted for each $2 in earnings you have above the annual limit ($14,640 in 2012).
In the year you reach your full retirement age, your benefits will be reduced $1 for every $3 you earn over a different limit ($38,880 in 2012) until the month you reach full retirement age. Then you get your full Social Security benefit payments, no matter how much you earn.
If you are younger than full retirement age and some of your benefits are withheld because your earnings are more than $14,640, there is some good news. When you reach full retirement age, your benefits will be increased to take into account those months in which you received no benefit or reduced benefits.
Also, any wages you earn after signing up for Social Security may increase your overall average earnings, and your benefit probably will increase.
For more information, ask for How Work Affects Your Benefits (Publication No. 05-10069).