How you qualify. You earn Social Security "credits" by working and paying payroll taxes (collected under the Federal Insurance Contributions Act, or FICA). You can earn up to four credits a year, and you need 40 credits — roughly 10 years of work — to qualify for a retirement benefit. Credits are earned on modest amounts of income (a few thousand dollars a year), so most people who work steadily clear the bar well before retirement.
How the benefit is calculated. Three steps turn a lifetime of paychecks into one monthly figure:
- AWI — Average Wage Index. The government's measure of economy-wide average earnings. It restates each old year of earnings in today's dollars, so a 1995 salary is weighed fairly against a recent one.
- AIME — Average Indexed Monthly Earnings. Your 35 highest indexed years, summed and divided into a monthly average.
- PIA — Primary Insurance Amount. The benefit you'd receive at your full retirement age (67). It's the anchor from which the COLA, the spousal 50%, the survivor 100%, and every early- or late-claiming adjustment are figured.
Two things follow. Zeros hurt: fewer than 35 working years means $0 fills the gaps and drags the average down — so an extra year or two of work late in your career can replace a zero and raise your benefit. And only earnings up to the annual wage base ($184,500 in 2026) count toward benefits and tax, so very high earners don't get proportionally higher benefits.
How the PIA formula works (2026)
Your AIME is split at two "bend points" and three fixed rates are applied, then added together:
Only the bend points move. The 90 / 32 / 15 rates are fixed in law and never change; the two dollar thresholds are re-indexed every year to the national Average Wage Index (AWI), so each birth-year cohort gets slightly different ones (for 2025 they were $1,226 and $7,391 — a 4.9% jump to 2026). The bend points that apply to you are locked in the year you turn 62, using the AWI from two years earlier, and don't change afterward.
Worked example — an AIME of $6,000: (90% × $1,286) + (32% × $4,714) + (15% × $0) = $1,157.40 + $1,508.48 + $0 = ≈ $2,666 a month at full retirement age. (SSA rounds the total down to the next lower dime, then adds each year's COLA.) This PIA is the figure the spousal 50% and survivor 100% amounts are computed from.
From a 35-year career to a monthly benefit
Meet Maria, who turns 62 in 2026. Social Security builds her benefit in three steps: index each year's earnings, average them into her AIME, then run that through the PIA formula above. (Figures are rounded for illustration.)
Step 1 & 2 Apply the AWI to each year, then average to get AIME
Every past year is multiplied by an indexing factor. The key rule: the top of that factor is always the AWI for the year the worker turns 60 — for Maria, the 2024 AWI. That single year's AWI is fixed for her forever, and it's divided by the AWI in each earlier year she worked, so indexing factor = (AWI in her age-60 year) ÷ (AWI in the year she earned the wages). This restates old paychecks in near-today's dollars. Earnings from age 60 onward are already current, so they aren't indexed at all — their factor is fixed at 1.00. Here are 5 representative years of her 35:
| Year | Age | Actual earnings | AWI that year | Indexing factor (age-60 AWI ÷ year's AWI) | Indexed earnings |
|---|---|---|---|---|---|
| 1992 | 27 | $23,000 | $23,000 | ×3.00 | $69,000 |
| 2002 | 37 | $40,000 | $34,500 | ×2.00 | $80,000 |
| 2012 | 47 | $62,000 | $46,000 | ×1.50 | $93,000 |
| 2020 | 55 | $78,000 | $57,500 | ×1.20 | $93,600 |
| 2024 | 60 | $71,000 | $69,000 | ×1.00 | $71,000 |
Across all 35 of her highest indexed years, the indexed earnings total $2,520,000. Divide by 420 months (35 years × 12): AIME = $2,520,000 ÷ 420 = $6,000/month.
Step 3 Run the AIME through the PIA bend-point formula
Her $6,000 AIME is split at the 2026 bend points ($1,286 and $7,749) and the three fixed rates are applied:
| Portion of AIME | Amount | Rate | Benefit |
|---|---|---|---|
| First $1,286 | $1,286 | 90% | $1,157.40 |
| $1,286 to $7,749 | $4,714 | 32% | $1,508.48 |
| Above $7,749 | $0 | 15% | $0.00 |
| Primary Insurance Amount (PIA) | ≈ $2,666/mo |
Maria's PIA ≈ $2,666 a month at her full retirement age of 67 — the anchor figure the COLA raises each year, and from which her spouse's 50% and any survivor's 100% are calculated.
AWI and indexing factors are rounded for a clean walkthrough; SSA rounds the final PIA down to the next lower dime. The bend points and indexing year lock in at age 62 and 60 respectively, so Maria's never change afterward.
Progressivity — a feature, not a bug. The formula deliberately replaces a larger percentage of income for lower earners than for higher earners. A modest earner might see Social Security replace 40%+ of their pre-retirement income; a high earner, far less. That's why Social Security matters most to lower- and middle-income retirees and is only one leg of the stool for higher earners.
Full retirement age and the COLA. Your FRA is 67 if you were born in 1960 or later (slightly earlier for older cohorts). You can claim as early as 62 or as late as 70, which changes the amount dramatically (Chapter 14). Each year, benefits receive a COLA — 2.8% for 2026 — tied to the Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W). The COLA applies to your PIA whether or not you've claimed, so delaying doesn't cost you inflation protection. (As Chapter 9 notes, CPI-W may understate the inflation retirees actually face.)
The spousal benefit — the 50% floor. This is the provision couples most often miss, and it's a valuable one: a spouse can receive a benefit of up to 50% of the higher earner's PIA. In practice, Social Security pays each spouse the greater of (a) their own earned benefit or (b) up to 50% of the other spouse's PIA. So a spouse who never worked, or earned much less, is effectively topped up to 50% of the higher earner's full benefit.
The 50% spousal top-up
Robert's PIA (his full-retirement-age benefit) is $2,800/month. His wife Susan spent years out of the paid workforce and her own earned benefit is only $700. Thanks to the spousal benefit, Susan can instead receive up to 50% of Robert's PIA = $1,400 (if she claims at her FRA). Her own $700 isn't added to it — she gets the larger figure, $1,400. That $700 top-up, for life and inflation-adjusted, is money many couples don't realize they're owed.
Two details matter. The spousal benefit is reduced if the spouse claims before their own FRA, so timing still counts. And unlike a worker's own benefit, the spousal benefit does not grow with delayed retirement credits — there's no bonus for a spouse to wait past their FRA to claim the spousal amount (the delayed credits the worker earns raise the survivor benefit, but never the spousal 50%, which is always figured from the worker's PIA). Divorced spouses can also claim on an ex's record if the marriage lasted at least 10 years.
Three claiming scenarios
Using Robert's $2,800 PIA — so a full spousal benefit of $1,400:
- Susan claims the spousal benefit early, at 62. Claiming five years before her FRA cuts it by 35% — from 50% of Robert's PIA down to 32.5%. Susan receives $910 instead of $1,400, and the reduction is permanent.
- Susan waits until 70 to claim the spousal benefit. It's still capped at the FRA amount, $1,400. Waiting past her FRA earns her nothing extra and forfeits three years of payments — there are no delayed-retirement credits on a spousal benefit.
- Robert delays his own claim to 70. His own check grows to about 124% of PIA — roughly $3,472. But Susan's spousal benefit is still 50% of his PIA, so it stays at $1,400 — not 50% of $3,472 ($1,736). Robert's delay boosts his own check and the eventual survivor benefit, never the spousal amount while both are alive.
Two filing rules that trip couples up. First, a spouse can't collect a spousal benefit until the higher earner has filed for their own retirement benefit. If Robert is delaying to 70, Susan can't start her spousal top-up until he files — the old "file and suspend" workaround that let a worker suspend benefits while a spouse collected was eliminated by the Bipartisan Budget Act of 2015. Second, deemed filing: for anyone born on or after January 2, 1954, filing for either your own retirement benefit or a spousal benefit is treated as filing for both, and you're paid the higher of the two. You can no longer submit a "restricted application" to take only the spousal benefit while letting your own retirement benefit grow with delayed credits — that strategy is closed to newer retirees.
The survivor benefit (previewing Chapter 14). When one spouse dies, the survivor keeps the larger of the two benefits — up to 100% of what the deceased was receiving, including any delayed-retirement credits the higher earner had earned. This is the single biggest reason the higher earner's claiming decision echoes through both lives: delaying to 70 maximizes not just their own check but the survivor's income for the rest of their life. We take that up in full in Chapter 14.
Why the higher earner's delay matters
Suppose Robert delayed to 70, so his check is $3,472 (124% of his $2,800 PIA), while Susan collects her $1,400 spousal benefit. Between them they're receiving two checks. When one spouse dies, the survivor keeps only the larger of the two — the smaller one stops. If Robert dies first, Susan's survivor benefit steps up to his full $3,472 — including every dollar of the delayed-retirement credits he earned — and her own $1,400 ends. Compare that with the alternative where Robert had claimed at his FRA for $2,800: Susan's survivor benefit would have been just $2,800. Robert's decision to wait added $672/month, for the rest of Susan's life. Because a survivor inherits delayed credits (but a spouse never does), delaying is often worth the most precisely when the higher earner expects the other spouse to outlive them.
Survivor benefits reach further than most people expect. They're paid on the deceased worker's record, so the survivor doesn't need 40 credits of their own — a spouse who never worked can still collect. And the deceased may not have needed a full 40 credits either: under a special rule, benefits can go to a worker's children and the spouse caring for them with as little as six credits (1½ years of work) in the three years before death. Beyond the surviving spouse, the record can support:
- Minor and student children — an unmarried child under 18 (or 19 if still in elementary or secondary school full-time) receives 75% of the deceased's benefit.
- Disabled adult children — a child disabled before age 22 can collect for life at 75%.
- A caregiving spouse of any age — a surviving spouse caring for the deceased's child who is under 16 (or disabled) receives 75% at any age, even well before 60. This "young survivor" benefit bridges the years until the spouse's own retirement-based survivor benefit begins.
- Dependent parents — a parent 62+ who relied on the worker for support may qualify.
Total payments to a family are capped by the family maximum (roughly 150–180% of the worker's PIA), and Social Security also pays a one-time $255 lump-sum death benefit to an eligible surviving spouse or child. The takeaway: even a worker who dies young, before building a full earnings record, may leave meaningful protection for a spouse and children.
A note on solvency. You may have heard Social Security's trust fund faces a shortfall projected around 2033; absent congressional action, benefits could be reduced to roughly the high-70s percent of scheduled amounts. This is a genuine policy issue, but Social Security remains a core, ongoing part of retirement income, and most planning still treats scheduled benefits as the baseline while acknowledging the uncertainty.