How Social Security retirement benefits are calculated

A Social Security retirement benefit is not based on the taxes a worker paid in or on an account balance. It comes from a formula applied to the worker's lifetime earnings record. Knowing the steps makes a benefit estimate easier to read and shows which career decisions change the result and which do not.

Step one: earning enough credits to qualify

Before any formula applies, a worker has to be insured. Social Security counts work in credits (officially, quarters of coverage), and a worker can earn up to four per year. For 2026, one credit is earned for each $1,890 of covered earnings, and for 2027 the amount is $1,970, according to the Social Security Administration's quarter of coverage table.

Under the agency's insured-status rules, a worker generally needs one credit for each year after age 21 up to the year they turn 62, and never more than 40. For most people that means 40 credits, or roughly ten years of work. Credits only determine eligibility. Earning more than 40 does not raise the benefit.

Step two: indexing past earnings

Wages from decades ago were paid in very different dollars, so Social Security adjusts, or indexes, each year's earnings to reflect the growth in average wages since then. The indexing rule works like this:

• Earnings are indexed to the national average wage for the year the worker turns 60, which is two years before first eligibility at 62.
• Each earlier year's earnings are multiplied by the ratio of the average wage in the indexing year to the average wage in the year the money was earned.
• Earnings at age 60 and later are counted at face value.

Only earnings up to the annual taxable maximum count. That cap is $184,500 for 2026 and $192,300 for 2027. Pay above the cap is not subject to Social Security tax and does not increase the benefit.

Step three: the highest 35 years

Social Security then selects the years with the highest indexed earnings, up to 35 of them. For a retirement benefit, the number of years used is the number of years from age 22 through age 61, minus five "drop-out" years. That comes to 35 years for a typical retiree.

The 35 highest years are added together and divided by the number of months in those years (420). The result, rounded down to the next lower dollar, is the average indexed monthly earnings, usually shortened to AIME.

Two consequences follow:

• Someone with fewer than 35 years of covered earnings has zeros averaged in, which lowers the AIME.
• Working an additional year can raise the benefit if that year's earnings replace a lower year or a zero among the 35. Social Security rechecks the record as new earnings are posted, including after benefits have started.

Step four: the benefit formula

The AIME goes through a three-part formula to produce the primary insurance amount, or PIA. The PIA is the monthly benefit payable at full retirement age. The dividing lines in the formula are called bend points, and they are set by the year the worker turns 62 (or becomes disabled or dies, if earlier). The agency publishes them in its bend point table.

The result is rounded down to the next lower ten cents.

A hypothetical example

Suppose a worker turns 62 in 2026 and has an AIME of $6,000. This is an illustrative figure, not a typical one.

1. 90% of the first $1,286 is $1,157.40.
2. 32% of the next $4,714 (the amount between $1,286 and $6,000) is $1,508.48.
3. Nothing falls above $7,749, so the third tier adds $0.

The total is $2,665.88, which rounds down to a PIA of $2,665.80 a month.

Why the formula favors lower earners

Because the first slice of earnings is replaced at 90% and the last slice at 15%, the benefit replaces a larger percentage of pay for someone with low lifetime earnings than for someone with high earnings. A higher earner still receives a larger benefit in dollars. This tilt is deliberate, and it is why doubling a salary does not double a future benefit.

From the formula amount to the actual check

The PIA is a starting point. Several adjustments happen before a payment arrives:

• Cost-of-living adjustments. Starting with the year a worker turns 62, the PIA is increased each year by the cost-of-living adjustment, whether or not benefits have started. The adjustment was 2.8% effective December 2025 and is 3.6% effective December 2026.
• Claiming age. The benefit is reduced if it starts before full retirement age and increased if it starts later, as explained in when to claim Social Security.
• Medicare premiums. For people enrolled in Medicare who receive Social Security, the Part B premium is generally deducted from the monthly benefit payment. See Medicare Parts A, B, C and D explained.
• Income tax. Part of the benefit may be taxable, depending on other income. See how Social Security benefits are taxed.

Checking the earnings record

Since every step depends on the earnings history, an error there carries through to the benefit. The Social Security Administration provides each worker's year-by-year record and benefit estimates through an online my Social Security account. Common things people look for are missing years, earnings posted under a former name, and self-employment income that was never reported.

Estimates on the statement generally assume the worker keeps earning at about the same level until the claiming age shown. Someone who stops working years earlier, or whose pay changes sharply, may see a different final figure. Benefits for a husband, wife or surviving spouse are based on the same PIA, which is covered in spousal and survivor benefits.