Article Title: FERS annuity supplement Computation
Snippet of Article: "...The FERS annuity supplement is computed as if you were age 62 and fully insured for a social security benefit when the supplement begins. OPM first estimates what your full career (40 years) social security benefit would be. Then we calculate the amount of your civilian service under FERS and reduce the estimated full career social security benefit accordingly. For example, if your estimated full career social security benefit would be $1,000 and you had worked 30 years under FERS, we would divide 30 by 40 (.75) and multiply ($1,000 x .75 = $750). The result would be your FERS annuity supplement, prior to any reductions...."
Source: www.opm.gov