Medicare Before 65: What You Need to Know

Medicare is the federal health insurance program primarily for people age 65 and older. Most people become eligible based on age, though some qualify earlier due to certain disabilities or medical conditions. For the majority of retirees, the key transition happens around age 65 — and the decisions made then can affect coverage and costs for years.

This is an educational overview. Medicare rules, premiums, and plan availability are subject to change, and individual situations vary.

The Initial Enrollment Period

Your Initial Enrollment Period (IEP) is a seven-month window that begins three months before the month you turn 65, includes your birthday month, and ends three months after. Enrolling during this window generally helps you avoid late penalties and coverage gaps.

Parts A and B

• Part A (hospital insurance) is generally premium-free if you or your spouse paid Medicare taxes for enough years. It covers inpatient hospital stays, skilled nursing, and some other services.
• Part B (medical insurance) covers doctor visits, outpatient care, and some preventive services. Most people pay a monthly premium for Part B.

Many people are automatically enrolled in both if they are already receiving Social Security benefits. If you are not yet receiving benefits, you generally need to enroll yourself.

When you might delay Part B

If you are still working at 65 and covered by an employer group health plan — your own or a spouse's — you may be able to delay Part B without a late penalty. This is one of the most important and most-missed nuances. Delaying Part B when you have qualifying employer coverage can be appropriate; delaying without qualifying coverage can trigger a permanent late-enrollment penalty.

The late enrollment penalty for Part B adds a surcharge to your premium for as long as you have Part B — typically 10% for each full 12-month period you were eligible but did not enroll. It is permanent.

Part D, Medicare Advantage, and Medigap

• Part D covers prescription drugs, offered through private insurers. Delaying Part D without other creditable drug coverage can also trigger a late penalty.
• Medicare Advantage (Part C) bundles Parts A, B, and usually D through a private insurer, often with networks and extra benefits. You remain enrolled in Medicare but receive care through the plan.
• Medigap (Medicare Supplement) helps pay some of the out-of-pocket costs (deductibles, coinsurance) of Original Medicare. Medigap and Medicare Advantage generally cannot be used together.

A key timing point: the best time to buy a Medigap policy is during your six-month Medigap Open Enrollment Period, which starts the month you are 65 and enrolled in Part B. During this window, you generally have guaranteed-issue rights regardless of health. After it closes, medical underwriting may apply.

HSAs, COBRA, retiree, and spouse coverage

• Health Savings Accounts (HSAs). If you are contributing to an HSA, you generally cannot make new HSA contributions in any month you are enrolled in any part of Medicare, including Part A. Some people delay Part A to keep contributing. This is a nuanced decision worth reviewing carefully.
• COBRA and retiree coverage. COBRA or retiree health plans are not generally considered "active" employer coverage for Part B delay purposes. Relying on them without enrolling in Part B can trigger late penalties.
• Spouse coverage. Being on a working spouse's employer plan can qualify you to delay Part B, but the rules around when that coverage ends matter.

IRMAA — income-related premium adjustments

Higher-income beneficiaries pay more for Part B and Part D through the Income-Related Monthly Adjustment Amount (IRMAA). IRMAA is based on your modified adjusted gross income from two years prior. Large one-time income events — such as a large retirement-account withdrawal or a Roth conversion — can push you into a higher IRMAA tier. This is another reason Medicare decisions connect to your broader retirement income and tax strategy.

Coordinating Medicare with retirement timing

When you retire affects when your employer coverage ends, which affects when you need Medicare, which affects your premiums and penalties. These decisions are connected. For many people, the cleanest approach is to map the Medicare timeline against the retirement timeline before either is finalized.

For dedicated Medicare guidance, our Medicare division can help. See our Medicare page and our guide on healthcare costs in retirement.