You log into your Social Security account and check your estimated benefit. It’s lower than you expected, maybe quite a bit lower. You worked for 26 years, took time off when the kids were small, figured that would be fine. It is not a mistake.
Social Security doesn’t calculate your benefit based on your last paycheck, your best decade, or even your career average. Your benefit amount is based on your 35 highest-earning years, adjusted for inflation, averaged together, and run through a formula to produce a monthly payment. If you have fewer than 35 years of earnings on record, each missing year gets a zero. Those zeros are averaged in like any other year, pulling your monthly check down permanently.
The average retired worker collected $2,071 a month in January 2026. A few gaps make more difference than most people expect.
How the 35-year formula actually works
The Social Security Administration takes every year of your earnings, adjusts each one upward to account for wage growth over time (a process called indexing), then picks the 35 best years. It adds those 35 years together and divides by 420, which is the number of months in 35 years. The result is called your Average Indexed Monthly Earnings, or AIME.
If you only worked 28 years, the formula doesn’t divide by 336 months. It still divides by 420. Your seven missing years are assigned zeros, those zeros are added to your real earnings, and the whole sum is divided by 420. You are being averaged over a longer window than you actually worked, which is what drives the benefit down.
Your AIME then gets fed into a formula that applies different percentages to different income tiers. In 2026, the first $1,286 of monthly AIME is replaced at 90 cents on the dollar. Earnings between $1,286 and $7,749 are replaced at 32 cents. Anything above $7,749 earns only 15 cents. Add those amounts together and you get your Primary Insurance Amount, which is the benefit you’d receive at full retirement age. The maximum possible benefit in 2026 is $4,152 at full retirement age, or $5,181 for those who wait until 70, but reaching that requires 35 years of maximum earnings.
Who ends up with the gaps
Women are disproportionately affected. Careers interrupted by caregiving, time at home with children, or following a spouse through job relocations show up as literal zeros in the earnings record. A worker who spent six years out of the workforce to raise children and another three working part-time has up to nine low or zero years dragging down her average.
Late starters run into the same problem from a different angle. Someone who went through graduate school and didn’t enter the workforce until 27 or 28 may simply not reach 35 full working years before a typical retirement age. A career that begins at 28 and ends at 62 covers 34 years. One short, and it shows in the math.
Job losses, serious illness, periods of unpaid caregiving for aging parents, and time spent on disability before qualifying for SSDI are all common sources of gaps. The formula doesn’t distinguish between a zero year because you chose not to work and a zero year because you couldn’t. Both count the same way.
More years of work directly improves the math
More work years solve the zero-year problem directly, and you do not need 35 consecutive years to get there. Returning to work after a gap fills in zeros and raises your AIME. A single year of part-time work in your early 60s can replace one of those zeros and push your monthly benefit up for the rest of your life.
Self-employment counts, as long as you file a Schedule SE and pay the 12.4 percent Social Security tax on your net earnings. Cash income that isn’t reported doesn’t go into your earnings record and doesn’t help your benefit. For self-employed workers, this is worth paying attention to, because underpaying or skipping that tax in a given year creates a zero just as effectively as not working at all.
The math works differently once you already have 35 years of earnings on record. At that point, each additional work year can only improve your average if the new year outearns your existing lowest year, which it often does for people still working at peak salary. But if you’re still filling in zeros, any new year of positive earnings provides a direct lift.
Your earnings record may have mistakes in it
Social Security calculates your benefit from wages your employers reported, and that record is not always accurate. Employer reporting errors, name changes after marriage or divorce that were never updated with the SSA, periods of self-employment where taxes weren’t filed, and plain data entry mistakes can all create gaps in the record that lower your benefit without you knowing.
You can check your full earnings history by creating a free account at SSA.gov and reviewing your Social Security statement. Look for years where you know you worked but the record shows $0 or an amount that seems obviously too low. This is worth doing every few years, not just when you’re close to retirement, because errors are easier to correct when documentation still exists.
If you find a discrepancy, you’ll need proof. W-2 forms, pay stubs, and tax returns are the standard documentation. IRS tax transcripts can cover self-employment income. Corrections made closer to the year of the error are usually smoother, but older corrections are still possible in many cases. The SSA has a correction request process and can be reached by phone or in person if you can’t resolve it through your online account.
A spousal or divorced spouse benefit can fill a thin record
If your own benefit is low because of a limited earnings history, and you are married or were married for at least 10 years, a spousal benefit is worth understanding before you file. A spouse who waits until full retirement age is entitled to up to 50 percent of the higher earner’s Primary Insurance Amount. If your own monthly benefit would be $700 and 50 percent of your partner’s PIA comes to $1,100, Social Security pays $1,100. You don’t receive both; the system compares and pays the higher amount automatically.
Claiming the spousal benefit before full retirement age reduces it. At 62, the earliest you can claim, a spousal benefit is reduced to 32.5 percent of the worker’s PIA. The spousal benefit also does not grow with delayed retirement credits the way your own earned benefit does, so there’s no advantage to waiting past full retirement age on the spousal side.
Divorced spouses qualify under the same rules if the marriage lasted at least 10 years, you have not remarried, and you are at least 62. If you have been divorced for at least two years, you can file even if your ex has not claimed benefits yet. Claiming a divorced spouse benefit has no effect on your former partner’s own benefit amount.
Delaying when you claim amplifies whatever benefit you’ve built
If your benefit is smaller because of gaps in your record, one way to partly offset that is to delay claiming. For every year you wait past your full retirement age, your benefit grows by 8 percent, up to age 70. Full retirement age is 67 for anyone born in 1960 or later. Waiting until 70 instead of claiming at 67 produces a benefit that is 24 percent higher for the rest of your life.
That increase applies to whatever base benefit you have built, including a reduced one. If your PIA is $1,200 at full retirement age, claiming at 70 instead of 67 brings it to about $1,488 a month. Over a 20-year retirement, the difference is more than $68,000. The tradeoff is that you receive no checks during those three extra years of waiting, so the calculation depends on your health and how long you expect to collect.
There is no benefit to waiting past 70. Delayed retirement credits stop accumulating at that point regardless of how long you continue to work.
A 2025 law changed Social Security for millions of public sector workers
If you spent part of your career working for a state or local government employer that did not withhold Social Security taxes, this matters. Teachers, police officers, and firefighters in many states fall into this category. For decades, two rules called the Windfall Elimination Provision (WEP) and the Government Pension Offset (GPO) reduced or eliminated Social Security benefits for workers who also received a pension from one of those non-covered jobs. The WEP was particularly punishing for people with mixed careers, since it reduced the 90 percent replacement rate in the lowest income tier of the benefit formula.
The Social Security Fairness Act, signed into law on January 5, 2025, repealed both provisions, effective retroactively to January 2024. The SSA distributed more than $17 billion in retroactive payments to over 3.1 million affected beneficiaries by mid-2025. If your monthly benefit was being reduced by WEP or GPO, those adjustments should have already taken effect. If you never applied for Social Security because the WEP or GPO reduction made it seem not worth pursuing, filing now may produce a benefit you weren’t expecting to have.
Not every teacher or public employee is affected. About 72 percent of state and local government workers are in Social Security-covered positions and paid into the system normally. The change only applies if your pension comes from a job where Social Security taxes were not withheld.
The 35-year rule is not changing, and its effects on any individual depend on what the earnings record actually shows and what options are still on the table. Both are worth checking well before you file.
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