- Lifetime earnings.
- Age at time of retirement.
Higher lifetime earning result in higher benefits. The highest 35 years are used to calculate average monthly earnings. Each year is indexed for inflation to approximate what earnings for that year would be in today’s dollars. Earnings for each year are also capped by the Social Security maximum earnings subject to Social Security tax for that year. After calculating the avberage indexed monthly earnings, a formula is used to determine the primary insurance amount (PIA).