The Defense Department officially launched the Blended Retirement System comparison calculator, providing BRS opt-in eligible service members their first opportunity for an individualized comparison of retirement systems. The comprehensive tool, in combination with the mandatory BRS Opt-In Course, will assist the nearly 1.7 million opt-in eligible service members and their families make an informed decision on whether or not to elect the new retirement system. The BRS goes into effect on Jan. 1, 2018.