New to Medicare: a plain-English starter guide

When you’re eligible, and when to sign up

Medicare is the federal health insurance program for people 65 and older (and some younger people with disabilities, ALS, or End-Stage Renal Disease). For most people, eligibility starts at 65.

Your Initial Enrollment Period: 7 months

You get a 7-month window to sign up for Part A and Part B: it starts 3 months before the month you turn 65, includes your birthday month, and ends 3 months after it.

Sign up in the first 3 months and coverage starts the month you turn 65. Sign up in your birthday month or later, and coverage starts the first day of the month after you sign up.

Already getting Social Security? You may not need to do anything

If you’ve been getting Social Security (or Railroad Retirement Board) benefits for at least 4 months before you turn 65, you’re signed up for Part A and Part B automatically. Your “Welcome to Medicare” package and card arrive by mail about 3 months before coverage starts. Part B has a monthly premium, so the package also explains how to turn it down if you have other coverage that makes waiting OK (see section 4).

Not getting Social Security yet?

Then you sign up yourself, online at SSA.gov, by phone, or at a Social Security office. You can sign up for Medicare without starting your Social Security retirement checks.

Sources: Medicare.gov: When can I sign up? · SSA.gov: Medicare benefits · Medicare.gov: Getting Social Security before 65 · CMS: 2026 premiums

Parts A, B, C and D in plain words

• Part A (Hospital Insurance): inpatient hospital stays, care in a skilled nursing facility (not long-term custodial care), hospice, and some home health care.
• Part B (Medical Insurance): doctor visits, outpatient care, many preventive services, lab tests, and medical equipment. You pay a monthly premium and a yearly deductible ($283 in 2026), then usually 20% of the Medicare-approved amount.
• Part C (Medicare Advantage): not a separate benefit but a different way to get A and B, through a Medicare-approved private plan (HMO, PPO and others). Most include drug coverage and some extras.
• Part D (drug coverage): prescription drug plans from private companies approved by Medicare. You get it as a stand-alone plan alongside Original Medicare, or inside a Medicare Advantage plan.

Original Medicare means Parts A and B run directly by the federal government. You can see any doctor or hospital in the U.S. that takes Medicare. It has no yearly out-of-pocket maximum on its own, which is why many people add a Medigap policy (next section).

Worth knowing: Medicare generally does not cover long-term custodial care, and Original Medicare doesn’t cover most routine dental, vision, or hearing care.

Sources: Medicare.gov: Parts of Medicare · Medicare.gov: 2026 Medicare Costs (PDF)

The big choice: two paths

When you first get Medicare, you pick one of two main ways to get coverage. Neither is “right” for everyone.

Medigap: the one-time window

Medigap (Medicare Supplement Insurance) is private insurance that helps pay your share of costs in Original Medicare. You can’t use it with Medicare Advantage.

Your Medigap Open Enrollment Period is 6 months long and starts the first month you have Part B and are 65 or older. During it, insurers must sell you any Medigap policy they offer in your state, and can’t turn you down or charge more because of health problems. It happens once, not every year. After it, you may be turned down or pay more (some states give extra rights; ask your state insurance department or SHIP).

Sources: Medicare.gov: Medigap basics · Medicare.gov: Buying a Medigap policy · Medicare.gov: Compare Original Medicare and Medicare Advantage

Still working at 65? Employer coverage and the Special Enrollment Period

If you (or your spouse) are still working and covered by that job’s group health plan, you may be able to delay Part B without a penalty. What matters most is the size of the employer:

• 20 or more employees: the job’s plan usually pays first. Many people take premium-free Part A at 65 and wait on Part B.
• Fewer than 20 employees: Medicare usually pays first, and the job’s plan might not pay for care if you don’t have both Part A and Part B. Ask the employer’s benefits office before you decide.

The 8-month Special Enrollment Period

When the job or the job-based coverage ends (whichever comes first), you get 8 months to sign up for Part B without a penalty. The clock starts when the work stops, even if you pick COBRA or retiree coverage. COBRA and retiree plans don’t count as coverage “from current work,” so don’t let them run out your 8 months.

When you sign up, you’ll fill out an extra form (CMS-L564) showing you had job-based coverage. To avoid a gap, sign up for Part B the month before the job coverage ends.

Have an HSA?

Once Medicare coverage starts, you can’t put new money into a Health Savings Account. Ask your benefits office or tax pro about timing before you sign up.

Sources: Medicare.gov: When can I sign up? · Medicare.gov: Signing up for Part A & Part B · CMS: Original Medicare enrollment

Late-enrollment penalties: the costly mistake

These aren’t one-time fees. They’re added to your monthly premium, usually for as long as you have that coverage.

• Part B: an extra 10% for each full 12-month period you could have had Part B but didn’t (and didn’t qualify for a Special Enrollment Period). Wait 2 full years and your premium is 20% higher, for life.
• Part D: an extra 1% of a national base amount for each month you went without Part D or other “creditable” drug coverage (coverage at least as good as Medicare’s) for 63 days or more in a row after your Initial Enrollment Period ends. It lasts as long as you have Medicare drug coverage.
• Part A: only if you have to buy Part A (most people don’t). The premium can go up 10%, for twice the number of years you didn’t sign up.

If you missed your window and don’t qualify for a Special Enrollment Period, the General Enrollment Period (January 1 – March 31 each year) lets you sign up for Part B, with coverage starting the month after you sign up, and the penalty may apply.

Sources: Medicare.gov: Avoid late enrollment penalties · Medicare & You (PDF)

Help with costs, free counseling, and the yearly review

Extra Help (drug costs)

A Medicare program for people with limited income and resources that lowers Part D premiums, deductibles and copays. People with full Medicaid, SSI, or a Medicare Savings Program get it automatically; others apply through Social Security. While you get Extra Help, there’s no Part D late penalty. Income limits change yearly: check Medicare.gov.

Medicare Savings Programs

State programs that can pay your Part B premium (and sometimes deductibles and coinsurance) if your income and savings are limited. Apply through your state Medicaid office (Medi-Cal in California). Applying for Extra Help through Social Security also starts an MSP application with your state unless you opt out.

Free, unbiased help: your SHIP

Every state has a State Health Insurance Assistance Program (SHIP): free, one-on-one Medicare counseling that doesn’t sell insurance. In California it’s called HICAP (Health Insurance Counseling and Advocacy Program): call 1-800-434-0222. Elsewhere, find yours at shiphelp.org or call 1-877-839-2675. Medicare itself is at 1-800-MEDICARE (1-800-633-4227).

Every fall: Open Enrollment, October 15 – December 7

Plans change their costs, drug lists and networks every year. During Open Enrollment you can join, switch or drop a Medicare Advantage or drug plan, or move between Original Medicare and Medicare Advantage. Changes start January 1. Read your plan’s “Annual Notice of Change” (mailed by the end of September) and compare plans at Medicare.gov/plan-compare.

If you’re in a Medicare Advantage plan, there’s also a Medicare Advantage Open Enrollment Period from January 1 to March 31 to switch plans or go back to Original Medicare (one change). If you go back to Original Medicare, a Medigap policy may not be guaranteed outside your one-time window.

Sources: Medicare.gov: Extra Help · Medicare.gov: Medicare Savings Programs · SHIP TA Center · California Dept. of Aging: HICAP · Medicare.gov: Open Enrollment

Your New to Medicare checklist

Tick things off as you go (your ticks stay in this browser only). Print it, or download the PDF to keep with your Medicare papers.

New to Medicare checklist

informedinsured.com/guides/new-to-medicare · Plain-English insurance education

About 3 months before your 65th birthday month IEP opens

• Mark your 7-month Initial Enrollment Period on a calendar (3 months before, birthday month, 3 months after).
• Already on Social Security? Watch the mail for your “Welcome to Medicare” package and card. If not, sign up at SSA.gov or call 1-800-772-1213.
• Working (or covered by a spouse’s job)? Ask the benefits office: how many employees, does Medicare pay first, and is the drug coverage “creditable”? Get answers in writing.
• Have an HSA? Plan when to stop contributions before Medicare starts.
• List your doctors, hospitals, and prescriptions (name, dose, pharmacy).
• Learn the two paths: Original Medicare (+ Medigap + Part D) vs. Medicare Advantage.
• Book a free counseling session with your SHIP (California: HICAP, 1-800-434-0222; others: shiphelp.org).
• Limited income? Check Extra Help and your state’s Medicare Savings Programs.

Your birthday month decide & enroll

• Sign up for Part A and Part B (or keep/decline Part B only if job-based coverage from current work lets you wait).
• Pick your path and enroll: a Part D plan (and Medigap if you want it), or a Medicare Advantage plan. Compare at Medicare.gov/plan-compare.
• Check every doctor and drug against the plan’s network and drug list before you join.
• If you want Medigap: note your 6-month Medigap Open Enrollment dates (they start when Part B starts and you’re 65+).

After Medicare starts settle in

• Carry your Medicare card (and plan cards); store the welcome letter and plan papers together.
• Tell doctors and pharmacies about your new coverage; end any Marketplace or other plan you no longer need so there’s no overlap.
• Delayed Part B for job coverage? Sign up the month before that coverage ends; you have 8 months from when work or coverage stops (COBRA doesn’t extend it).
• Book your free “Welcome to Medicare” preventive visit (within the first 12 months of Part B).
• Make an account at Medicare.gov to see claims and coverage.

Every fall Oct 15 – Dec 7

• Read your plan’s Annual Notice of Change (arrives by the end of September).
• Re-check doctors, drugs, and costs; compare plans during Open Enrollment (changes start Jan 1).
• Re-check Extra Help / Medicare Savings Programs if your income or savings changed.

Education only, not insurance advice. Informed Insured doesn’t sell insurance. Dates and costs change; confirm at Medicare.gov, 1-800-MEDICARE (1-800-633-4227), or SSA.gov, and get free help from your SHIP (shiphelp.org; California HICAP 1-800-434-0222). Version 2.13.0, October 2026.