The month in which your Social Security recalculation occurs depends on the type of recalculation performed. The recalculation that is performed for the annual COLA usually occurs in November, and the increase will take effect the following January. However, recalculations due to additional work history usually occur as soon as the Social Security Administration receives your W-2 or tax information from the prior year. This could be as late as April or May in some cases; however, the adjustment will be retroactive to January of that year.