You worked 38 years, paid Social Security taxes on every paycheck, and your online statement says you'll get $2,400 a month at 67. But where did that number come from? And can you trust it?
The answer to both questions requires understanding a formula that most financial advisors gloss over: the AIME-to-PIA calculation. It involves indexing decades of earnings for wage growth, averaging 35 years down to a single monthly number, and then running that number through a progressive formula with two "bend points."
It's not intuitive. But once you see the math, you can spot exactly where your benefit has room to grow, and where it doesn't.
30-Second Summary: Social Security averages your 35 highest-earning years (adjusted for wage growth), converts that to a monthly figure called AIME, then applies a three-bracket formula using "bend points" that replaces 90% of low earnings, 32% of middle earnings, and 15% of high earnings. The result is your Primary Insurance Amount (PIA): the check you'd get at full retirement age.
Step 1: Gathering Your Earnings Record
The Social Security Administration keeps a year-by-year record of every dollar you earned that was subject to Social Security tax. You can see yours by logging into ssa.gov/myaccount.
This record only includes earnings up to the taxable maximum for each year. Earned $200,000 in 2020? Only $137,700 shows up, because that was the cap. Earned fifty grand? All of it counts.
Mistakes happen. Employers misreport. Name changes cause matching errors. The SSA itself has acknowledged processing backlogs. If a year shows $0 and you know you worked, fixing it now could be worth hundreds of dollars per month in retirement. You'll need W-2s or tax returns as proof.
Step 2: Indexing Your Past Earnings
A dollar earned in 1995 isn't the same as a dollar earned in 2025. The SSA adjusts your older earnings upward using an "indexing factor" tied to the Average Wage Index (AWI).
Here's how it works in practice. Say you earned $30,000 in 1995. The SSA multiplies that by a factor that reflects how much average wages have grown since then. If the factor is roughly 2.5, your 1995 earnings get indexed to $75,000 for purposes of the benefit calculation [1].
This is a crucial detail that most benefit guides skip: your early career earnings often look much larger after indexing than you'd expect. That $18,000 you earned in your first real job might index to $50,000 or more. Conversely, earnings after age 60 are used at face value, without indexing [1]. So a $60,000 salary at age 63 stays $60,000 in the calculation.
I find it weirdly satisfying to go back and see what my first part-time job "really" paid after indexing. It's like retroactively getting the raise you deserved.
Step 3: Selecting Your Top 35 Years
After indexing, the SSA sorts your annual earnings from highest to lowest and picks the top 35 years. Those 35 figures get added together, then divided by 420 (that's 35 years × 12 months) to produce your Average Indexed Monthly Earnings (AIME).
If you worked fewer than 35 years, the missing years are filled in as zeros. Every zero drags down the average. Someone with 30 years of work history has five $0 years averaged in, which can reduce the monthly benefit by several hundred dollars.
This is also why working a 36th, 37th, or 38th year can help: if your current salary (after indexing) is higher than any of your previous 35 years, it replaces the lowest one, pushing up your AIME.
Step 4: The Bend Point Formula
This is the heart of the system. Your AIME gets split into three brackets, each replaced at a different rate. The dollar thresholds between brackets are called "bend points," and they change every year.
2026 Bend Points [2]:
- First bend point: $1,286
- Second bend point: $7,749
The formula:
- 90% of the first $1,286 of your AIME
- 32% of AIME between $1,286 and $7,749
- 15% of AIME above $7,749
| AIME Bracket | Replacement Rate | Purpose |
|---|
| $0 to $1,286 | 90% | Protects low earners |
| $1,286 to $7,749 | 32% | Middle-income replacement |
| Above $7,749 | 15% | High earners get diminishing returns |
The design is deliberately progressive. A worker earning $20,000 a year replaces a much larger share of their income than a worker earning $150k. This is Social Security acting as a safety net, not a 1:1 retirement account.
Worked Example: Michael's Benefit
Michael was born in 1964 and turns 62 in 2026. He's been a mid-career professional earning between $50,000 and $90,000 over his career. After indexing all historical wages and selecting his top 35 years, his total indexed earnings come to $2,520,000.
Calculating AIME:
$2,520,000 ÷ 420 months = $6,000 AIME
Applying 2026 bend points:
| Bracket | Calculation | Monthly Amount |
|---|
| 90% of first $1,286 | $1,286 × 0.90 | $1,157.40 |
| 32% of $1,286 to $6,000 | $4,714 × 0.32 | $1,508.48 |
| 15% of amount over $7,749 | $0 × 0.15 | $0.00 |
| PIA (at FRA) | | $2,665.80 |
Michael's PIA is $2,665.80. That's his monthly check if he claims at exactly 67.
If Michael claims at 62: He takes a roughly 30% permanent reduction. $2,665.80 × 0.70 = about $1,866 per month.
If Michael waits until 70: He gets three years of delayed retirement credits at 8% per year. $2,665.80 × 1.24 = about $3,305 per month.
The difference between 62 and 70? Nearly $1,440 per month. Over 20 years, that gap adds up to over $345,000 in lifetime income. Our article on when to claim Social Security breaks down the breakeven math in detail.
Three Scenarios Compared
Let's see how the formula treats different earning levels, all using 2026 bend points:
| Earner Profile | AIME | PIA at FRA | % of Pre-Retirement Income Replaced |
|---|
| Low ($28k/yr career avg) | $2,333 | $1,492 | ~64% |
| Mid ($72k/yr career avg) | $6,000 | $2,666 | ~44% |
| High ($150k+ career avg) | $10,000 | $3,563 | ~36% |
The pattern is clear. Social Security is designed to keep low-income retirees above the poverty line, not to maintain the lifestyle of high earners. If you're in that high-earning bracket, you'll need substantial savings in 401(k)s, IRAs, or other accounts to close the gap.
What the SSA Estimator Gets Wrong
The online estimator at ssa.gov projects your future benefit based on one big assumption: that you'll keep earning your current salary every year until your claiming age.
For someone planning to retire at 55 and claim at 62, this is wildly inaccurate. The estimator might show $2,200 per month, but your actual benefit could be $1,800 because you'll have seven years of $0 earnings dragging down the average.
If you're planning early retirement or a career change, you'll get a more accurate picture by downloading your actual earnings history from ssa.gov, plugging those numbers into the SSA's "Detailed Calculator" (available at ssa.gov/oact/anypia/anypia.html), and entering your expected future earnings as $0 for the years you won't be working.
The difference can be eye-opening. Use our compound interest calculator alongside these projections to see how investment income might fill the gap.
What Raises (and Lowers) Your Benefit
Things that increase your PIA:
- Working a 36th+ year that replaces a lower-earning year in your top 35
- Earning above previous years' indexed amounts
- Correcting errors on your earnings record
Things that lower your PIA:
- Fewer than 35 years of work (zeros averaged in)
- Years of very low earnings
- Errors or missing earnings on your SSA record
Things that don't affect your PIA calculation but change your check:
- Claiming early (permanent reduction, up to 30% at 62)
- Delaying past FRA (8% increase per year, up to age 70)
- COLA adjustments (applied annually to your PIA starting at age 62, whether or not you've claimed) [3]
That last point surprises people. COLAs start applying to your PIA at 62, even if you delay claiming until 70. You don't miss out on inflation adjustments by waiting. Learn more in our article on how Social Security COLA works.
Your Next Move
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Log into ssa.gov/myaccount and download your earnings record. Check every year for accuracy. Missing earnings from 10 years ago could cost you $50 to $100 per month in retirement.
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Count your work years. If you're at 32 or 33 years, three to four more years of work (even part-time above the credit threshold) eliminates those zeros in the average.
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Run the real formula. Use the SSA's Detailed Calculator or the AnyPIA program (free at ssa.gov) with your actual earnings. Don't rely on the basic estimator if your future plans differ from your current salary.
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Look at the bend points. If your AIME is near $1,286 or $7,749, small changes in earnings can have outsized effects on your benefit. Below the first bend point, every additional dollar of AIME adds 90 cents to your monthly check. Above the second, it's only 15 cents.
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Factor in spousal benefits. If your PIA is less than half your spouse's PIA, spousal benefits could top you up. The calculation changes when two earners are involved.
References
- Congressional Research Service. (2026). Social Security: Benefit Calculation Overview. Congress.gov. https://www.congress.gov/crs-product/IF11747
- Social Security Administration. (2025). Primary Insurance Amount. SSA.gov. https://www.ssa.gov/oact/cola/piaformula.html
- Social Security Administration. (2025). Cost-of-Living Adjustment (COLA) Information for 2026. SSA.gov. https://www.ssa.gov/cola/
- Social Security Administration. (2025). Benefit Reduction for Early Retirement. SSA.gov. https://www.ssa.gov/oact/quickcalc/early_late.html
- Bipartisan Policy Center. (2025). Social Security Benefit Formula. BipartisanPolicy.org. https://bipartisanpolicy.org/explainer/social-security-benefit-formula/
