How Social Security Benefits Are Calculated
Your Social Security check isn't a mystery — it's a formula based on your top 35 earning years and the age you claim. Here's how the pieces fit together.
Last updated: 2026-07-21
Social Security is the backbone of most Americans' retirement income, yet few people know how the benefit is figured. It comes down to two things: your lifetime earnings record and the age at which you start claiming.
Step one: your average earnings
Social Security takes your 35 highest-earning years, adjusts each for wage inflation, and averages them into a monthly figure called your AIME (average indexed monthly earnings). If you worked fewer than 35 years, the missing years count as zeros, which drags the average down — one reason a few extra working years can raise your benefit.
Step two: the benefit formula
Your AIME is run through a progressive formula with bend points that replaces a high share of low earnings and a smaller share of high earnings. The result is your primary insurance amount (PIA) — the monthly benefit you would receive at your full retirement age, which is 67 for anyone born in 1960 or later.
Step three: the age you claim
- Claim as early as 62 and your benefit is permanently reduced, by up to about 30%.
- Claim at full retirement age (66-67) and you receive 100% of your PIA.
- Delay past full retirement age and your benefit grows about 8% per year until age 70.
That is a large swing. Someone who would get $2,000 a month at full retirement age might get roughly $1,400 at 62 or about $2,480 at 70. The right choice depends on your health, other income, and whether you have a spouse whose benefit is tied to yours.
Estimate your benefit at different claiming ages with the calculators below.