Many seniors are surprised to find out that their Social Security benefits are taxable, and the bill can be significant. The amount that is taxable for an individual earning $25K to $34K is 50%, while if you make more than $34K then 85% of your benefits are probably taxable. What to do when you don’t want a surprise come April 15 is to fill out Form W-4V with The Social Security Administration requesting an amount to be withheld for taxes. The choices are 7%, 10%, 12% and 22%. These percentages apply to the full income, not the 50% or 85% that is taxable. Most states, including California, do not tax Social Security income.