Turning 65: A Medicare Sign-Up Checklist

Turning 65 comes with a deadline most people have never had to think about. Medicare gives you a 7-month Initial Enrollment Period — it opens 3 months before the month you turn 65 and closes 3 months after that month. Sign up in those first 3 months and your Part B coverage begins the month you turn 65; wait until your birthday month or later and coverage starts the month after you sign up. Social Security handles the actual sign-up, and missing the window can mean waiting for coverage plus a monthly late enrollment penalty for as long as you have Part B.

What the Initial Enrollment Period Is and Why It Matters at 65

Medicare is the federal health insurance program most people become eligible for at age 65. It comes in parts, and each part pays for something different.

• Part A is hospital insurance. It covers inpatient hospital stays and certain other care.
• Part B is medical insurance. It covers doctor visits and outpatient care.
• Part D is prescription drug coverage.

The moment that matters most is your Initial Enrollment Period. According to Medicare.gov, it generally begins when you turn 65, lasts 7 months, starts 3 months before the month you turn 65, and ends 3 months after the month you turn 65.

Think of it as a door that opens early, stays open for a while, and then closes. If you walk through it on time, your coverage begins smoothly. If you miss it, Medicare says you may have to wait to sign up and may pay a monthly late enrollment penalty for as long as you have Part B coverage — and that penalty goes up the longer you wait. A penalty can also apply if you have to pay a premium for Part A, sometimes called “Premium-Part A.”

One detail that trips people up: if your birthday falls on the first of the month, Medicare treats your timing differently. Medicare.gov has a note specifically for that situation on its coverage-start page, so check it rather than assuming.

Who actually signs you up

Medicare does not take your enrollment. The Social Security Administration does. Medicare.gov directs people to contact Social Security to sign up for Part A and/or Part B, change an address, apply for Extra Help with drug costs, or confirm that they meet Medicare’s citizenship or residency requirements.

Some people are enrolled automatically because they are already receiving Social Security benefits. Many are not. If you are not sure which group you are in, do not guess — call Social Security or 1-800-MEDICARE and ask.

If you are still working and have employer coverage

The rules are genuinely different for people who have health coverage through a job — their own or a spouse’s — and the right answer depends on the size of the employer and the type of coverage. Rather than guessing from a general article, use Medicare’s own question tool at medicare.gov’s “When can I sign up?” page, which walks you through your specific situation. Also note that Medicare.gov flags a separate consideration for anyone contributing to a Health Savings Account (HSA), so read that section before you enroll.

What Medicare.gov Actually Says About When Coverage Starts

Here’s what the official rules actually show. Coverage always starts on the first of a month, and the exact month depends on when during your 7-month window you sign up.

If you qualify for premium-free Part A, Medicare.gov says your Part A coverage starts the month you turn 65. If your birthday is on the first of the month, it starts the month before you turn 65.

For Part B — and for Part A if you have to pay a premium for it — the start date follows this table from Medicare.gov:

If you sign up	Coverage starts
Before the month you turn 65	The month you turn 65
The month you turn 65, or during the 3 months after	The next month

The practical lesson is simple. Signing up in the first 3 months of your window is the only way to have Part B in place on the day you turn 65. Every month you delay inside the window pushes your start date out.

There is one more rule worth knowing. Medicare.gov says you can sign up for premium-free Part A any time after you turn 65, and that coverage starts 6 months back from when you sign up or apply for Social Security benefits — but never earlier than the month you turned 65.

Why the gap matters more than it sounds

A one-month gap in medical coverage feels abstract until it is not. An unexpected fall, a hospital stay, a new prescription, or a scan ordered during a routine visit can all land in that uncovered month.

If you are retiring and your employer coverage is ending, line up the dates before you give notice. Coverage always starts on the first of the month, so a plan that ends on the 15th leaves two uncovered weeks unless you have planned around it.

What Original Medicare still leaves you to pay

Original Medicare — Part A and Part B together — does not pay everything. You are still responsible for costs such as deductibles, copayments and coinsurance. There is a yearly Part B deductible, and the amounts change every year.

Because those figures are updated annually, do not rely on a number you read anywhere other than the source. Check the current amounts at Medicare’s costs page.

Your Step-by-Step Checklist for the 7-Month Window

Work through these in order. The timing is what protects you.

Step 1 — Mark the window on your calendar now

Count back 3 months from the month you turn 65. That is the day your window opens. Count forward 3 months past your birthday month. That is the day it closes. Write both dates down.

If you want coverage to begin the month you turn 65, aim to sign up in those first 3 months.

Step 2 — Find out whether you will be enrolled automatically

Contact the Social Security Administration and ask directly. Medicare.gov lists SSA as the place to sign up for Part A and/or Part B, and SSA can also confirm that you meet Medicare’s citizenship or residency requirements. Do not assume automatic enrollment because a friend got a card in the mail.

Step 3 — Decide about Part B before the window closes

Most people take Part B when first eligible. If you have employer coverage and are considering delaying, run your situation through Medicare’s question tool first. Medicare.gov is explicit that missing the 7-month window may mean waiting to sign up and paying a monthly late enrollment penalty for as long as you have Part B.

Step 4 — Know what you need before joining a health or drug plan

If you want to add coverage beyond Original Medicare, Medicare.gov says you generally must have Part A and/or Part B, be a U.S. citizen or national, a lawful permanent resident, a Cuban-Haitian entrant, or lawfully living in the U.S. as a COFA migrant, and live in the plan’s service area. You will also need your Medicare Number and your Part A and/or Part B coverage start dates, which appear on your Medicare card.

To join a Medicare Advantage Plan (Part C), with or without drug coverage, you need both Part A and Part B. Your Initial Enrollment Period is also when you can first join a plan, and the same 7-month timing applies.

Step 5 — Protect your 6-month Medigap window

Medicare Supplement Insurance, called Medigap, is extra insurance sold by private companies to help pay your share of out-of-pocket costs in Original Medicare — copayments, coinsurance and deductibles. You can only buy it if you have Original Medicare, which generally means signing up for Part A and Part B first.

Medicare.gov describes a 6-month Medigap Open Enrollment period that starts the first month you have Part B and are 65 or older. During that window you can enroll in any Medigap policy and the insurance company cannot deny you coverage because of pre-existing health problems. After that period, you may not be able to buy a Medigap policy, or it may cost more. This window is easy to miss because nothing announces it.

Step 6 — Make one list of your prescriptions and supplements

Before any coverage conversation, write down every prescription drug you take, with the dose. Add your vitamins and supplements to the same list — they matter for your doctor and pharmacist even though Medicare does not cover them. Our guide to supplements and medications explains which combinations deserve a pharmacist’s review, particularly if you take blood thinners, statins, or blood-pressure medications.

What to Watch For and What to Ignore

Turning 65 brings a wave of mail, phone calls and advertising. Most of it is marketing, not information.

Go to the source, not the mailbox

Coverage rules, enrollment dates and cost figures live on Medicare.gov. Sign-up lives with the Social Security Administration. Anything else — a mailer, a television ad, a website that asks for your phone number — is selling something. That does not make it dishonest, but it is not the official record.

Be cautious with any message that creates urgency or asks for personal details. Medicare will not call you out of the blue to ask for your Medicare Number.

Dollar figures change every single year

Premiums, deductibles and coinsurance amounts are updated annually. If you read a specific dollar amount in an article, a forum post or an old brochure, assume it is out of date and verify it on Medicare’s costs page.

Plans vary, and nobody can tell you yours from the outside

Medicare Advantage plans must cover what Original Medicare covers. Anything beyond that varies from plan to plan. No article — including this one — can tell you what a particular plan pays for your situation. Read the plan’s Evidence of Coverage document, or call the plan directly and ask.

What Medicare does not cover

Original Medicare does not pay for vitamins, minerals or dietary supplements. Those stay out of pocket, so it is worth being honest with yourself about which ones are earning their place in your routine. Two of our most-read reviews of the evidence are do you actually need a multivitamin after 50 and how much fish oil a 65-year-old should take.

Where to Get Official Answers

The bottom line: three sources can answer almost any Medicare question you have, and all three are free.

• Medicare.gov — the official source for coverage rules, enrollment periods and current cost figures. Its “when can I sign up” question tool handles the employer-coverage cases that general articles cannot.
• 1-800-MEDICARE (1-800-633-4227) — you can talk or live chat with a real person 24 hours a day, 7 days a week, except some federal holidays. TTY users can call 1-877-486-2048.
• Your State Health Insurance Assistance Program (SHIP) — free, one-on-one counseling in your state. Counselors do not sell anything.

To sign up for Part A or Part B, change your address, apply for Extra Help with drug costs, or confirm citizenship or residency requirements, contact the Social Security Administration. For help lowering your Medicare costs through a Medicare Savings Program or Medicaid, contact your state.

And where a service needs a doctor’s order, ask your doctor whether it is medically necessary for you — that is the standard Medicare applies. This is also a good moment to bring your full medication and supplement list to your doctor or pharmacist and consult them about anything you are unsure of, ideally before your new coverage begins.

Sources:

• Medicare.gov — When does Medicare coverage start? — Source for the 7-month Initial Enrollment Period, the coverage-start table, premium-free Part A start date, the 6-month retroactive Part A rule, the late enrollment penalty description, and the HSA and first-of-the-month notes.
• Medicare.gov — When can I sign up for Medicare? — Question tool referenced for readers with employer coverage whose rules differ.
• Medicare.gov — Joining a plan — Source for plan eligibility requirements, the need for the Medicare Number and coverage start dates, the service area rule, and the requirement to have both Part A and Part B to join a Medicare Advantage Plan.
• Medicare.gov — Get Medigap Basics — Source for what Medigap is, the requirement to have Original Medicare, and the 6-month Medigap Open Enrollment period with guaranteed issue.
• Medicare.gov — Talk to someone — Source for 1-800-MEDICARE, TTY 1-877-486-2048, 24/7 availability, Social Security’s role in sign-up, and contacting your state for Medicare Savings Programs.
• Medicare.gov — Medicare costs — Where readers check current-year premium, deductible and coinsurance amounts.