The Basic Formula: Your Earnings History Determines Your Payment

Your SSDI payment is based on your Primary Insurance Amount (PIA), which Social Security calculates from your earnings record. The formula takes your highest 35 years of earnings, adjusts them for inflation, and applies a percentage-based calculation that favors lower earners. You do not choose this amount — Social Security's computer system calculates it automatically when you reach full retirement age, whether or not you claim benefits yet.

The actual payment you receive each month depends on when you started receiving SSDI. If you claimed before your full retirement age, your payment is reduced by a percentage. If you waited past full retirement age, your payment increases. The reduction or increase applies for the rest of your life, so the timing of your claim directly affects every check you receive.

Social Security publishes the exact formula each year, but the percentages and bend points (the income thresholds where the formula changes) shift annually. This means two people with identical earnings histories born in different years will have different PIAs.

Key Takeaways

  • Your payment is based on your 35 highest-earning years, adjusted for inflation, not on how much you paid into Social Security.
  • The formula uses bend points that change each year, so the exact calculation depends on your birth year and when you claim.
  • Claiming before full retirement age permanently reduces your monthly payment; claiming after full retirement age permanently increases it.
  • You can see your estimated payment on your Social Security account or by calling 1-800-772-1213 to request a detailed earnings record.
  • If you worked outside the United States, those earnings may or may not count depending on the country and the tax treaty in place.

How Social Security Counts Your Earnings Years

Social Security uses your 35 highest-earning years to calculate your benefit. If you have fewer than 35 years of earnings on record, the formula includes zeros for the missing years, which lowers your payment. This is why people who took time out of the workforce — for caregiving, illness, or other reasons — often have lower benefits than they might expect.

The earnings must be covered by Social Security, meaning your employer withheld Social Security tax from your paycheck. Self-employment income counts if you paid self-employment tax. Government jobs, railroad work, and some other employment may not be covered, depending on when you worked and what tax system applied.

Social Security adjusts your historical earnings for inflation using a factor called the National Average Wage Index. This means your 1990 earnings are not compared directly to your 2020 earnings — they are adjusted upward to reflect what that money would be worth in today's dollars. The adjustment happens automatically; you do not need to do anything.

The Bend Points: Why Lower Earners Get a Higher Percentage

Once Social Security has your adjusted earnings history, it applies the bend point formula. This formula gives you a higher percentage of your early earnings and a lower percentage of your later earnings. The idea is to replace a larger share of income for people who earned less.

For someone born in 2024, the formula might look like this: 90% of the first $1,174 of your average monthly earnings, plus 32% of earnings between $1,174 and $7,078, plus 15% of earnings above $7,078. (These numbers change every year.) A person who averaged $2,000 a month would receive roughly $1,056 + $192 = $1,248. A person who averaged $6,000 a month would receive roughly $1,056 + $1,888 + $56 = $3,000 — a higher amount, but a lower percentage of their actual earnings.

The bend points are published by Social Security each October for the following year. If you want to see what your specific bend points are, you need to know your birth year, because the formula changes based on when you were born.

Reductions for Claiming Before Full Retirement Age

If you claim SSDI before you reach full retirement age, your payment is reduced. The reduction is permanent — it applies to every check for the rest of your life, even after you reach full retirement age.

The reduction rate depends on how many months early you claim. For someone whose full retirement age is 67, claiming at 62 results in a reduction of about 30%. Claiming at 65 results in a reduction of about 13%. The exact percentage varies slightly depending on your birth year. These reductions are built into the system; there is no way around them.

This is why some people choose to wait: the higher monthly payment can add up to more total money over a lifetime, especially if you live into your 80s or 90s. But if you need the money now, or if you have reason to believe you will not live a long time, claiming earlier makes sense despite the permanent reduction.

Increases for Claiming After Full Retirement Age

If you wait past your full retirement age to claim SSDI, your payment increases by a percentage for each month you delay. This increase is called a delayed retirement credit. The credit stops at age 70, so there is no financial benefit to waiting past that point.

The increase rate is about 8% per year, or roughly 0.67% per month. Someone whose full retirement age is 67 who waits until 70 receives about 24% more per month than they would have at 67. Like the reduction for early claiming, this increase is permanent.

Waiting is a gamble: you receive fewer total checks, but each check is larger. The break-even point is usually in your early 80s, meaning if you live past that age, you will have received more total money by waiting.

How to Find Your Estimated Payment

The easiest way to see what Social Security estimates your payment will be is to create an account on ssa.gov. Once you log in, you can view your earnings record and see an estimate of your benefit at different claiming ages. The estimate is based on your actual earnings history and the current bend points.

If you do not have an online account, you can call Social Security at 1-800-772-1213 and ask for a detailed earnings record and benefit estimate. You can also visit your local Social Security office in person. The office address is on ssa.gov, and you can search by zip code.

The estimate you receive is not a may provide of your actual payment — it is based on the assumption that you continue working until you claim and that your earnings stay roughly the same. If you stop working, earn significantly more or less, or have a gap in your work history, your actual payment will be different.

Special Situations: Government Work, Non-Covered Earnings, and International Work

If you worked for a government agency that did not participate in Social Security — such as some state or local government jobs — those years may not count toward your 35-year history. This is called the Government Pension Offset or Windfall Elimination Provision (WEP), depending on your situation. The WEP can reduce your benefit by up to 50% of the government pension you receive.

If you worked in another country, Social Security may or may not count those earnings. The United States has tax treaties with some countries that allow earnings to be credited, but not with all. You will need to contact Social Security directly with information about where and when you worked to find out whether those years count.

Self-employment income counts only if you paid self-employment tax. If you were paid in cash and did not report the income to the IRS, Social Security has no record of it and cannot count it. The earnings record Social Security uses is based on what was reported to the IRS.

What Happens to Your Payment If You Continue Working

If you claim SSDI before full retirement age and continue to work, your benefit may be reduced or suspended depending on how much you earn. This is called the earnings test. For every $2 you earn above a certain amount, Social Security withholds $1 from your benefit. The earnings limit changes each year.

Once you reach full retirement age, the earnings test no longer applies, and you can earn as much as you want without affecting your benefit. However, if you continue working and earning, those new earnings may be high enough to replace one of your lower-earning years in the 35-year history, which could increase your benefit slightly. This recalculation happens automatically.

If you are still working and have not claimed yet, continuing to work may increase your benefit because recent high-earning years replace older, lower-earning years in the calculation. The longer you work, the more likely your recent earnings will push out a zero or a low-earning year.

Frequently Asked Questions

Can I see the exact formula Social Security used to calculate my payment?

Yes. When you view your benefit estimate on ssa.gov or request one by phone, Social Security shows your Primary Insurance Amount and the bend points used. You can also ask for a detailed explanation of the calculation at your local Social Security office. The formula itself is published each year on ssa.gov.

If I worked part-time for many years, will my payment be lower?

Yes. Social Security uses your 35 highest-earning years, so part-time years with lower earnings will lower your average. If you have fewer than 35 years of work history, zeros are included in the calculation, which also lowers your payment. The formula does not adjust for how many hours you worked.

Does my spouse's earnings affect my SSDI payment?

No. Your SSDI payment is based only on your own earnings record. Your spouse may be able to receive a separate benefit based on your record, but that does not change your payment. If you are married and both receive SSDI, each payment is calculated separately.

What if Social Security made a mistake in my earnings record?

You can request a correction by contacting Social Security with proof of the correct earnings — usually a W-2 or tax return. Social Security will investigate and correct the record if the error is confirmed. Corrections can take several months. You should check your earnings record every few years to catch errors early.

Will my SSDI payment increase each year?

Your payment increases each year if there is a Cost of Living Adjustment (COLA). Congress approves the COLA amount, which is based on inflation. Not every year has a COLA — it depends on whether inflation occurred. Social Security announces the COLA in October for the following year.