How Your Social Security Benefit Is Calculated

Your Social Security retirement benefit isn't based on your final salary or your last paycheck — it's based on your lifetime earnings, run through a fixed formula. There are three steps: index your past earnings for wage growth, average your highest 35 years into a single monthly figure, then apply a progressive benefit formula. Here is how each step works.

Step 1: Your highest 35 years of earnings

Social Security looks at every year you worked and paid Social Security taxes, keeps your 35 highest-earning years, and ignores the rest. If you worked fewer than 35 years, the missing years count as $0 and pull your average down — so additional working years can replace a zero or a low-earning year.

Only earnings up to the annual taxable maximum count ($184,500 in 2026). Income above that cap is not taxed for Social Security and does not increase your benefit.

Step 2: Indexing and your AIME

Older earnings are indexed so that a dollar you earned decades ago is measured against today's wage levels. Social Security adjusts each year's earnings using the national average wage index, up through the year you turn 60; earnings from age 60 onward are counted at face value.

It then adds up your 35 highest indexed years and divides by 420 (35 years × 12 months). The result is your Average Indexed Monthly Earnings (AIME) — the single number the benefit formula is built on.

Step 3: The PIA formula (the "bend points")

Your Primary Insurance Amount (PIA) — the benefit you would receive at full retirement age — comes from applying three percentages to your AIME, split at two dollar thresholds called bend points. For 2026 the bend points are $1,286 and $7,749:

• 90% of the first $1,286 of AIME
• 32% of AIME between $1,286 and $7,749
• 15% of AIME above $7,749

A worked example

Suppose your AIME works out to $6,000:

• 90% × $1,286 = $1,157.40
• 32% × ($6,000 − $1,286) = 32% × $4,714 = $1,508.48
• Nothing falls in the third tier, because $6,000 is below $7,749.

Add them together: about $2,665 per month at full retirement age. (Social Security rounds the result down to the next lower dime.)

What changes the final number

The PIA is your benefit at full retirement age. Two things adjust it from there:

• When you claim. Claiming before your full retirement age permanently reduces the amount; delaying past it adds delayed retirement credits up to age 70. See our guide on full retirement age and claiming.
• Cost-of-living adjustments. Once you are eligible, annual COLAs raise your benefit to keep pace with inflation.

Why the formula favors lower earners

Notice the percentages fall from 90% to 32% to 15%. That is deliberate: Social Security replaces a larger share of income for lower earners than for higher earners. It is designed as social insurance, not a personal savings account.

To estimate your own number, try our benefits estimator, and confirm the official figure in your my Social Security account.

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This article is for general education and is not financial advice.