Is The Federal Tax Withholding On Social Security Benefits Based On The Gross Or Net Benefit Amount?

Oct 11 2018 - 6:59am

Is monthly federal withholding tax on Social Security benefits calculated on the full benefit amount or on the amount remaining after the premium for Medicare Part B is deducted? For example, if my full benefit is $1,000 and I elect 10 percent withholding, is my monthly tax $100 ($1,000 x .10) or $86.60 ($1,000 - $134 = $866 x .10)? Many thanks.


I'm sorry, but I can't give you a definite answer. I thought that the withholding was based on the gross amount before other deductions, but I recently received a question from another reader that indicates the withholding is based on the net amount. Social Security's website isn't clear on this subject (, so I'm afraid you'll need to check with Social Security for an answer.

Best, Jerry