If you were born in 1958, your Social Security full retirement age is 66 years and 8 months. Filing your claim in the month you reach that age pays 100 percent of your primary insurance amount, the base monthly figure calculated from your lifetime earnings. File earlier and the monthly check is permanently smaller. Wait longer, up to age 70, and it grows.
Why the Age Is 66 and 8 Months
Federal law sets full retirement age on a sliding scale tied to birth year. Under 42 U.S.C. ยง 416, workers who turned 62 between 2017 and 2021 have a full retirement age of 66 plus a gradually increasing number of months. People born in 1958 turned 62 in 2020, which places them in the fourth year of that five-year phase-in and lands them at 66 and 8 months.1GovInfo. 42 USC 416 – Additional Definitions For anyone born in 1960 or later, full retirement age levels off at 67.
Your primary insurance amount itself comes from your highest 35 years of inflation-adjusted earnings. The Social Security Administration averages those earnings, divides by the total number of months, and applies a benefit formula to produce the monthly figure you receive at full retirement age.2Social Security Administration. Social Security Benefit Amounts Fewer than 35 years of earnings means zeros fill the empty slots and pull the average down.
What Claiming at 62 Costs You
You can start collecting as early as age 62, but the reduction is permanent. The Social Security Administration cuts your primary insurance amount by 5/9 of one percent for each of the first 36 months you claim before full retirement age, and by 5/12 of one percent for every additional month beyond those 36.3Social Security Administration. Code of Federal Regulations 404-0410 – How Does SSA Reduce My Benefits When My Entitlement Begins Before Full Retirement Age?
For someone born in 1958, claiming at 62 means filing 56 months early. The first 36 months carry the larger reduction, totaling 20 percent. The remaining 20 months add roughly another 8.33 percent. Combined, your benefit drops by about 28.33 percent. A worker whose primary insurance amount would have been $1,000 at full retirement age would instead receive about $717 per month at 62.4Social Security Administration. Benefits Planner: Retirement – Retirement Age and Benefit Reduction
The reduced check does not reset when you reach full retirement age. It stays reduced for life. Annual cost-of-living adjustments still apply, but they compound on the smaller base.
What Waiting Past 66 and 8 Months Pays
If you delay filing past full retirement age, you earn delayed retirement credits worth two-thirds of one percent for every month you wait. That comes to 8 percent per year. Credits stop accumulating at age 70, so waiting beyond that gains you nothing.5Social Security Administration. Delayed Retirement – Born in 1958
For a 1958 birth year, the gap between full retirement age and 70 is 40 months. Waiting the full 40 months raises your benefit to 126.7 percent of your primary insurance amount.5Social Security Administration. Delayed Retirement – Born in 1958 That higher check then becomes your permanent base for all future cost-of-living adjustments.
Delayed retirement credits also carry through to a surviving spouse. If you accumulate credits by waiting past full retirement age and later die, your surviving spouse’s benefit is calculated using your primary insurance amount plus the credits you earned.6Social Security Administration. Code of Federal Regulations 404-0313 – What Are Delayed Retirement Credits and How Do They Increase My Old-Age Benefit Amount?
Working Before You Reach Full Retirement Age
Claiming benefits before 66 and 8 months while still earning wages triggers the retirement earnings test. In 2026, the annual earnings limit is $24,480 for anyone under full retirement age for the entire year. For every $2 you earn above that limit, the Social Security Administration withholds $1 in benefits.7Social Security Administration. Receiving Benefits While Working
In the calendar year you actually reach full retirement age, a higher limit takes over. For 2026, that limit is $65,160 for the months before your birthday, and the withholding rate drops to $1 for every $3 earned above it.7Social Security Administration. Receiving Benefits While Working Once you hit 66 and 8 months, the earnings test disappears entirely. You can earn any amount with no reduction.
Money withheld under the earnings test is not lost. When you reach full retirement age, the Social Security Administration recalculates your benefit to credit you for the withheld months, and your monthly amount goes up going forward.8Social Security Administration. Program Explainer: Retirement Earnings Test
Medicare Comes at 65, Not at Full Retirement Age
Because your full retirement age is 66 and 8 months, you become eligible for Medicare roughly 20 months before you can claim your full Social Security benefit. Your initial Medicare enrollment period is a seven-month window that starts three months before the month you turn 65 and ends three months after it.9Medicare.gov. When Does Medicare Coverage Start
If you are already collecting Social Security when you turn 65, enrollment in Medicare Parts A and B is generally automatic.10Centers for Medicare & Medicaid Services. Original Medicare (Part A and B) Eligibility and Enrollment If you are waiting to file until full retirement age or later, you need to sign up for Medicare yourself during that seven-month window. Missing it can add a Part B late-enrollment penalty of 10 percent to your monthly premium for each full 12-month period you were eligible but did not enroll, unless you had qualifying employer coverage.11Medicare.gov. Avoid Late Enrollment Penalties
How to Apply
You can file for retirement benefits up to four months before the month you want payments to start.12Social Security Administration. Timing Your First Payment Three routes are available: the online application at ssa.gov, a call to the Social Security Administration at 1-800-772-1213, or an in-person visit to your local field office.13Social Security Administration. Form SSA-1 – Information You Need to Apply for Retirement Benefits or Medicare
Have these ready before you start:
- Your Social Security number.
- An original birth certificate or a copy certified by the issuing agency. Photocopies and notarized copies are not accepted.
- Proof of citizenship or lawful status, if you were not born in the United States.
- W-2 forms or self-employment tax returns for the most recent year.
- A bank routing and account number for direct deposit.
The application asks for identification details, employment history, and the month you want benefits to begin. Your first payment arrives the month after the enrollment month you choose.14Social Security Administration. What Documents Do You Need to Apply for Retirement Benefits?
If You’re Already Past 66 and 8 Months
Filed late? You can request up to six months of retroactive payments. The Social Security Administration will not pay retroactive benefits for any month before you reached full retirement age, or more than six months back, whichever is later.15Social Security Administration. Delayed Retirement Credits Taking the lump sum means giving up the delayed retirement credits you would have earned during those months, so your ongoing monthly check will be slightly lower in exchange.