The Social Security Administration uses a person's highest-earning annual income over the course of 35 years, and then uses a formula by applying those figures to create the primary payment amount, explains AARP. The formula consists of a set of calculations that help average out the payments between lower- and higher-wage earners.
The Social Security Administration uses a greater percentage of the lower-wage earner's income than for the high-wager earners for a retirement benefit payment. The Social Security Administration also reports the annual income as zero for years that people did not earn wages over the last 35 years of their lives in which they worked, reports AARP.
There are a few different ways to increase the monthly benefits, U.S. News & World Report advises. People should work at least 35 years and increase their income over that time frame. If people delay their retirements, they should see an increase in benefits, up to the age of 70. Every year a person works after he's retired means 8 percent in increased benefits up to the age of 70, if the worker does not claim his Social Security benefit during that time.
The Social Security website has a benefit calculation chart for people who are retiring 2015 to estimate their benefit payment, explains the Social Security Administration.