@Jvisme
All of the tax estimators that have been suggested will have you enter your wages and your Social Security benefits separately. They will then calculate the tax on your wages plus the appropriate percentage of your Social Security, and give you one combined tax amount. You cannot calculate the tax separately on each type of income because each one affects the other. As far as withholding is concerned, it doesn't matter how much you have withheld from your pay and how much you have withheld from your Social Security. All that matters is that the total withholding for the year approximately covers your total tax for the year.
