Biden estimated the bill should lead to an average monthly increase of $360 for certain public employees and their spouses and survivors. The outgoing president said more than 2.5 million Americans will receive a lump sum payment worth "thousands of dollars" to compensate for the benefits they should have received last year.

The best way to see how much your Social Security benefit would be at age 69 is to log in to your account at www.ssa.gov (or create one if you haven't yet) and view your latest Social Security statement. Here you'll find an estimate for various ages based on your actual work record.