How is my Social Security benefit actually calculated?

Your benefit is based on your highest 35 years of earnings, indexed for wage inflation. Social Security averages those 35 years into your AIME (Average Indexed Monthly Earnings), then runs it through a progressive formula to get your PIA (Primary Insurance Amount) — the benefit you'd receive at your full retirement age. If you worked fewer than 35 years, the missing years count as zeros, which drags your average down. That's why an extra year or two of solid earnings late in your career can replace a zero and bump your check. The formula deliberately replaces a higher share of income for lower earners. Your PIA is then adjusted up if you delay past full retirement age, or down if you claim early. To see how different claiming ages change your lifetime total, try wealthserene.com/tools/social-security-optimizer.