Social Security: how benefits are calculated

In short

A friend of mine opened his Social Security statement last spring and stared at it for a good while. He had no idea how the government got to that number. You are probably in the same spot, and there is nothing foolish about that. The benefit rests on your own work record, which is yours to check and yours to understand. The Social Security Administration (SSA) counts your 35 highest earning years, adjusts them for wage growth, and turns the average into a monthly check. When you claim matters a great deal, because the same record pays less at 62 than at full retirement age. Your free account at ssa.gov shows your actual record, so look for errors there. A few quiet minutes with it can raise or protect what you receive.

The whole of it

What it is

I once watched an old farmer settle a dispute over a fence line with nothing but a tape measure and a patient attitude. Social Security benefits work much the same way. There is a measuring process, and it follows written rules. If you are holding a statement and wondering where the figure came from, the answer is a formula set by law.

The monthly benefit you earn through your own work is called the primary insurance amount. People call it the PIA. It is the amount you receive if you claim at your full retirement age. Claim earlier and it shrinks. Claim later and it grows.

The PIA is built from your average earnings over your working life. Not every year counts the same, and not every dollar is treated the same either. That sounds complicated. Walk through it once and it makes sense.

How it works

A neighbor of mine thought the government simply took his last five years of pay and averaged them. Plenty of people believe that. The real method looks at your whole career instead.

First, the SSA takes your earnings from each year you paid Social Security tax. It adjusts older years upward to reflect how wages have grown across the country. This keeps a paycheck from 1995 from looking tiny next to one from today. Only earnings up to the yearly taxable maximum count, and that cap is set by law.

Next, the SSA picks your 35 highest adjusted years. If you worked fewer than 35 years, the missing years count as zero. Zeros pull the average down, which is worth knowing.

Then it adds up those 35 years and divides by 420, the number of months in 35 years. The result is your average indexed monthly earnings, or AIME. Short and plain, that is your starting number.

Now comes the part built to help people with lower pay. The SSA runs your AIME through three brackets. It takes 90 percent of the amount in the first bracket, 32 percent of the amount in the second, and 15 percent of the amount above that. The dollar lines between the brackets are called bend points, and they change each year. The sum of those three slices is your PIA. A worker with modest earnings gets back a bigger share of past pay than a worker with high earnings.

Last, timing adjusts the check. The benefit may be claimed as early as age 62, but the monthly amount is permanently reduced. Waiting past full retirement age earns delayed retirement credits, up to age 70. Cost of living increases are added each year after that.

The numbers, and where to find yours

If you are wondering which numbers are yours, start with your own record. Your earnings history and a benefit estimate live in your my Social Security account at ssa.gov. The SSA also publishes its official formula details, bend points, and wage index on its website, in the section on how your benefit is figured.

The figures that change by year are these. The first bend point is the current figure, which the official source publishes each year. The second bend point is the current figure, which the official source publishes each year. The taxable maximum on earnings is the current figure, which the official source publishes each year. Your full retirement age is the current figure, which the official source publishes each year, and it depends on the year you were born. The earliest claiming age is the current figure, which the official source publishes each year. Delayed credits stop at age the current figure, which the official source publishes each year. The SSA states each of these on its own pages, and the site fills in the verified figure with its source and date.

Check your own earnings record line by line. If a year looks low or missing, the SSA has a process to correct it, and the sooner the better.

A worked example

Let me tell you about a woman named Marlene. She is 62 and has worked steadily as a bookkeeper. To keep the math easy to follow, I will use round numbers of my own. These are not the official bend points.

Say the SSA finds her 35 best adjusted years add up to $1,680,000. She divides that by 420 months. $1,680,000 divided by 420 is $4,000 a month. That is her AIME.

Now picture simple brackets, again just for this story. The first $1,000 is paid at 90 percent. The next $3,000 is paid at 32 percent. Anything above $4,000 is paid at 15 percent, but Marlene has nothing above that.

The first slice is 90 percent of $1,000, which is $900. The second slice is 32 percent of $3,000, which is $960. The third slice is 15 percent of $0, which is $0. Add them up. $900 plus $960 plus $0 is $1,860. That is Marlene's PIA in this story.

Now timing. Suppose her full retirement age is 67, and claiming at 62 cuts her check by 30 percent. That cut is another round figure of mine. Thirty percent of $1,860 is $558. Subtract it. $1,860 minus $558 is $1,302 a month.

So the same record gives her $1,860 at 67 or $1,302 at 62. The gap is $558 every month. Over a year that is $558 times 12, or $6,696. Her work record did not change. Only her claiming date did.

Where it goes wrong

I have a great respect for people who check their work, because most mistakes are small ones that nobody caught. A few come up again and again.

A missing year of earnings is the biggest one. If an employer reported pay under the wrong name or number, the SSA may have no record of it. That year could count as a zero, and a zero hurts the average.

Another snag is fewer than 35 working years. Someone who stepped away to raise children or care for a parent may have several zero years. Adding even one more year of work can replace a zero with real earnings.

People also mix up the estimate with a promise. The figure on a statement assumes things about your future pay and the law. It can move. Treat it as a good map, not a signed contract.

Early claiming trips folks up too. The reduction is permanent. Many people claim at 62 without seeing the monthly difference for life, and that is a hard thing to undo. The SSA allows a withdrawal of an application only within narrow limits, so the borrower of that choice, so to speak, is stuck with it.

Last, some forget that other rules touch the check. Working while claiming before full retirement age can trigger an earnings test, which holds back some benefits. Benefits may also be taxed depending on total income. The SSA and the IRS each explain these rules on their own pages.

Questions to answer before you leave this page

Have you logged into your my Social Security account and looked at every year of your earnings record? Do all of those years match what you remember earning, and are any years missing or too low? How many years have you worked so far, and could a few more years replace some zeros in your top 35? What is your full retirement age, and how much does your monthly check change if you claim a year earlier or a year later? Have you looked at the SSA's own benefit calculators to see your estimate under different claiming ages? Do you know whether you plan to keep working while you collect, and how the earnings test might apply to you? And have you talked with a spouse or someone close to you about how your choice affects them, since survivor and spousal benefits depend on the record too?