What is the primary factor for taxing Social Security benefits?

The primary factor for taxing Social Security benefits is combined income. Combined income refers to the total amount of income a taxpayer has, which includes adjusted gross income (AGI), any nontaxable interest, and half of the Social Security benefits received. This figure determines how much of the Social Security benefits will be subject to federal income tax.

As combined income increases, so does the possibility of a portion of Social Security benefits being taxable. For individuals whose combined income exceeds certain thresholds, up to 85% of their Social Security benefits can be taxed. This is why understanding combined income is essential for determining the tax implications of receiving Social Security benefits, which is central to this question.

While marital status does play a role in determining the thresholds for taxing Social Security benefits, it is not the primary factor. The age of the beneficiary and employment status are also not directly related to how Social Security benefits are taxed. Instead, they may influence other aspects of income and tax scenarios, but the taxation of Social Security benefits hinges primarily on the level of combined income.