PIA definition
The "primary insurance amount" (PIA) is the benefit (before rounding down to next lower whole dollar) a person would receive if he/she elects to begin receiving retirement benefits at his/her normal retirement age. At this age, the benefit is neither reduced for early retirement nor increased for delayed retirement.

PIA formula bend points
The PIA is the sum of three separate percentages of portions of average indexed monthly earnings. The portions depend on the year in which a worker attains age 62, becomes disabled before age 62, or dies before attaining age 62.

For 2015 these portions are the first \$826, the amount between \$826 and \$4,980, and the amount over \$4,980. These dollar amounts are the "bend points" of the 2015 PIA formula. A table shows bend points, for years beginning with 1979, for both the PIA and maximum family benefit formulas.

PIA formula
For an individual who first becomes eligible for old-age insurance benefits or disability insurance benefits in 2015, or who dies in 2015 before becoming eligible for benefits, his/her PIA will be the sum of:
(a) 90 percent of the first \$826 of his/her average indexed monthly earnings, plus
(b) 32 percent of his/her average indexed monthly earnings over \$826 and through \$4,980, plus
(c) 15 percent of his/her average indexed monthly earnings over \$4,980.
We round this amount to the next lower multiple of \$.10 if it is not already a multiple of \$.10.

Determination of the PIA bend points for 2015
Amounts in
formula
Average wage indices
For 1977:9,779.44
For 2013:44,888.16
Bend points for 1979
First:\$180
Second:\$1,085
Computation of bend points for 2015 First bend point
\$180 times 44,888.16 divided by 9,779.44 equals \$826.21, which rounds to \$826
Second bend point
\$1,085 times 44,888.16 divided by 9,779.44 equals \$4,980.21, which rounds to \$4,980