Q. I am a 66-year-old federal retiree. My Social Security statement says my benefit at 66 is $1,004 per month, and I have less than 25 years of substantial earnings. Because of my federal retirement, I know my benefit will be reduced, but by how much? Some Social Security information seems to say it will be reduced by about 50 percent; other information leads me to believe the maximum reduction is $362 per month. A. Go to http://ssa.gov/estimator and use the benefits calculator provided by the Social Security Administration.