How is your Social Security benefit calculated?

1. The benefit is a formula, not a mystery

When the Social Security Administration shows you an estimated benefit, it isn’t guessing and it isn’t arbitrary. It’s the output of a fixed, published formula that the same agency applies to every worker in the country. Learn the three steps and you stop being a passenger: you can see exactly how one more year of work, a higher salary, or a different claiming age changes your check.

Here is the whole thing in one breath: Social Security averages your 35 best earning years, runs that average through a progressive bend-point formula to get your full-retirement benefit, then adjusts it up or down based on the age you claim. The rest of this article is just those three steps, slowed down.

2. Step 1: your top 35 years (AIME)

Social Security looks at your entire earnings history and picks your 35 highest-earning years. Each year’s earnings are first indexed — scaled up for national wage growth so that a salary you earned in 1995 is measured in today’s dollars. The agency indexes your record to the year you turn 60, sums the 35 best indexed years, and divides by 420 (that’s 35 years × 12 months). The result is your Average Indexed Monthly Earnings (AIME).

Two consequences fall straight out of this. First, if you worked fewer than 35 years, the empty slots are filled with zeros — and those zeros drag your average down hard. Second, working an extra year late in your career can replace an early low-earning year, nudging your AIME (and benefit) upward even at the end. Only earnings up to the annual taxable maximum count; in 2026 that cap is $184,500.

3. Step 2: the bend-point formula (PIA)

Your AIME now runs through the famous bend-point formula to produce your Primary Insurance Amount (PIA) — the benefit you’d receive at full retirement age, before any early or delayed adjustment. The formula slices your AIME at two dollar thresholds (the bend points) and replaces each slice at a different rate. For workers first eligible in 2026, the bend points are $1,286 and $7,749:

So the first $1,286 of your monthly average is replaced generously at 90 cents on the dollar; the big middle band is replaced at 32%; and anything above $7,749 earns just 15%. Add the three pieces and you have your PIA. One important detail: the bend points are locked in the year you turn 62. Even if you wait until 70 to file, your benefit is computed with the bend points from your year-62 cohort.

4. Why the formula favors lower earners

That 90% / 32% / 15% structure isn’t random — it’s deliberately progressive. A modest earner has most of their AIME sitting in the 90% slice, so Social Security replaces a large share of their working income. A high earner has filled the 90% and 32% slices and is adding dollars only in the 15% band, so each extra dollar of lifetime earnings buys very little additional benefit.

This is why two people with very different salaries end up with benefits that are far closer together than their paychecks ever were. It’s also why a lower-earning spouse often does better claiming a spousal benefit than their own, and why the highest earners get the most mileage from delaying rather than from one more year of work.

5. Step 3: your claiming age

Your PIA is what you receive at full retirement age (FRA), which is now 67 for everyone born in 1960 or later — the long phase-in is finally complete. But you don’t have to claim at 67. File earlier and your benefit is permanently reduced; wait and it permanently grows.

Claim at the earliest age of 62 and your check is cut to about 70% of your PIA — a 30% haircut for life. Wait past FRA and you earn delayed retirement credits of 8% per year up to age 70, where the benefit tops out at 124% of PIA. Nothing else about your record changes; the same PIA simply gets multiplied by a claiming factor:

We walk through how to choose among those rows — especially for federal retirees with a pension and the FERS supplement in the mix — in our federal-edition guide to when to claim.

6. Estimate your own benefit

The calculator below runs the real 2026 formula. Enter your AIME if you know it, or estimate it from your average monthly earnings, then slide your claiming age. It shows your PIA, the three bend-point slices that built it, and your adjusted monthly check.

Estimates use the 2026 bend points ($1,286 / $7,749), a full retirement age of 67, and standard early/delayed factors. Your actual benefit depends on your full indexed earnings record; treat this as a close approximation, not an official quote.

7. The federal twist: WEP repeal

For decades, two rules quietly shrank Social Security for many public servants. The Windfall Elimination Provision (WEP) cut the worker’s own benefit if they had a pension from work not covered by Social Security — classic CSRS territory. The Government Pension Offset (GPO) did the same to spousal and survivor benefits. Both are now gone.

The Social Security Fairness Act, signed in January 2025, repealed WEP and GPO. Federal retirees under CSRS, along with affected teachers, firefighters, and police in non-covered systems, now have their benefits calculated with the standard formula above — no special reduction. If an older statement still shows a WEP-reduced number, it reflects the pre-repeal rules; the benefit actually payable today is figured without it. We cover the rollout in our dispatch on the WEP/GPO repeal, one year later.

8. Five things that move your number

Once you can see the formula, the levers become obvious. Here are the five that matter most:

None of these change the formula — they change the inputs you feed it. That’s the whole game: the formula is fixed, but the numbers you bring to it are largely yours to shape.

9. Frequently asked questions