To adjust your historical income for inflation, Social Security uses the Average Wage Index (AWI), a measure of average national income subject to federal income taxes plus contributions to deferred compensation plans like a 401(k). Social Security indexes your historical earnings based on the year you turn 62 (the soonest you can claim Social Security), but because there's a two-year lag to its AWI measure, your income is actually inflation-adjusted by the AWI for the year you turn age 60. To do that, you need to wait until age 70 to begin drawing benefits.