One of the most common questions retirees ask is, “At what age does Social Security stop being taxed?” It’s an understandable question, especially since many people assume that once they reach a certain birthday (perhaps full retirement age, age 70, or even 75), the IRS stops taxing their benefits. The truth, however, surprises many Americans: there is no age at which Social Security benefits automatically become tax-free at the federal level. Instead, whether your benefits are taxed depends largely on your income and tax filing status, not your age. Here’s a look at six key things every retiree should know about how Social Security benefits are taxed.