When Medicare Is Required and When It's Optional

Medicare is not automatically required, but most people over 65 must sign up or face penalties

You do not have to use Medicare, but if you are 65 or older and do not sign up when you first become may be able to access, you will owe a penalty on your premiums for as long as you have Medicare. The penalty is permanent — it does not go away after a few months. The only people who can skip Medicare without penalty are those with current health coverage through an employer or a spouse's employer that meets certain standards, or members of certain religious groups that have formal exemptions.

If you have no other coverage and do not sign up during your initial enrollment window, you will pay more later. Understanding when you must sign up and what counts as "coverage" that lets you wait is the difference between a small premium and a larger one for life.

Key Takeaways

• You must sign up for Medicare at 65 unless you have current employer coverage or may have access to for a religious exemption; missing the important date costs you a permanent premium increase.
• Employer coverage counts only if it is active and comes from your current job or your spouse's current job — retiree coverage or COBRA do not count as a reason to delay.
• Your initial enrollment window is the three months before the month you turn 65, the month you turn 65, and the three months after — eight months total to sign up without penalty.
• If you miss your window and have no other coverage, you can still sign up during the general enrollment period (January 1 to March 31 each year), but the penalty will explore.
• Part A (hospital insurance) and Part B (doctor visits) have separate enrollment rules and separate penalties, so you can be penalized on one, both, or neither depending on your situation.

When employer coverage means you can delay Medicare

If you or your spouse are still working and have health insurance through that job, you can delay Medicare without penalty. The coverage must be active right now — not something you had in the past or will have in the future. It must come from a current employer with 20 or more employees, or from your spouse's current employer with 20 or more employees.

Retiree health plans do not count, even if your former employer offers them. COBRA coverage does not count. Medicare Advantage plans do not count. Only active group health insurance from a current employer qualifies.

When you or your spouse stops working, you have eight months from the end of employment to sign up for Medicare without penalty. This eight-month window is separate from your initial enrollment window at 65. If you turn 65 while still employed with coverage, your initial window still opens three months before you turn 65 — but you can choose not to sign up during it. Once you leave the job, the eight-month clock starts.

Your initial enrollment window at 65

Your initial enrollment window is seven months long: the three months before the month you turn 65, the month you turn 65 itself, and the three months after. If you turn 65 in June, your window runs from March through September.

During this window, you can sign up for Part A, Part B, or both without any waiting period or medical review. After this window closes, if you did not sign up and you have no may have access to employer coverage, you will owe a penalty on Part B premiums of 10 percent for each full year you were may be able to access but not signed up. The Part A penalty is 10 percent as well, but Part A is usually free for people 65 and older, so the penalty is less common.

You do not have to sign up for Part D (prescription drug coverage) during your initial window if you have other drug coverage that is considered "creditable" — meaning it covers drugs at least as well as Medicare does. If you do not have creditable coverage and you do not sign up for Part D during your initial window, you will owe a penalty on Part D premiums later.

What happens if you miss your window

If you do not sign up during your initial enrollment window and you have no employer coverage, you can still sign up during the general enrollment period, which runs January 1 through March 31 each year. Coverage begins July 1 of that year. However, the penalty applies from the month you became may be able to access until the month you actually sign up.

The penalty is calculated as a percentage of the standard Part B premium for that year. In 2024, the standard Part B premium was $164.90 per month; a penalty of 10 percent would add $16.49 per month. The exact amount changes each year because the standard premium changes. Your penalty is recalculated each January and stays with you as long as you have Medicare.

If you have a gap of more than 12 months between when you became may be able to access and when you sign up, you may also face a waiting period before Part B coverage begins. Part A has no waiting period, but Part B can be delayed by up to six months.

Religious exemptions and other exceptions

Members of certain religious groups that have formal objections to insurance and have been recognized by the Social Security Administration can request an exemption from the Medicare requirement. This is not common, and the exemption must be requested in writing with documentation of your religious affiliation and beliefs. The exemption covers both the requirement to sign up and the penalty.

Other exceptions are narrower. If you are still working past 65 and have employer coverage, you are not required to sign up, but this is not an exemption — it is a deferral. You will still need to sign up eventually, and the eight-month window after you stop working is your chance to do so without penalty.

Part A and Part B have separate rules

Part A (hospital insurance) and Part B (doctor and outpatient services) have separate enrollment periods and separate penalties. You can be required to sign up for one but not the other, depending on your situation.

Part A is usually free for people 65 and older if they or their spouse paid Medicare taxes while working. Most people do not owe a penalty for not signing up for Part A because they do not have to pay a premium for it. However, if you do have to pay a Part A premium and you miss your window, the penalty applies.

Part B always has a premium, and the penalty for missing your window is more common. If you have employer coverage and delay Part B, you will not owe a penalty. If you do not have employer coverage and delay Part B, you will owe the penalty.

How to sign up and avoid penalties

You can sign up for Medicare online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. You will need your Social Security number, proof of citizenship or legal residency, and information about any current health coverage.

If you are still working with employer coverage, you do not need to do anything right now. When you leave your job, contact Social Security or Medicare within eight months to sign up. If you are 65 and have no employer coverage, sign up during your initial enrollment window to avoid the penalty.

If you are unsure whether your employer coverage qualifies as a reason to delay, ask your employer's benefits department or call Medicare at 1-800-MEDICARE. It is better to ask before you miss your window than to find out later that you owe a penalty.

Frequently Asked Questions

Can I turn down Medicare if I do not want it?

You can choose not to sign up, but you will owe a penalty on your premiums if you do not have may have access to employer coverage. The penalty is permanent and applies every month you have Medicare. If you have active employer coverage, you can delay without penalty, but once you leave that job, you must sign up within eight months or face the penalty.

Does my spouse's employer coverage count if I am not working?

Yes, if your spouse is still working and you are covered under their employer health plan, you can delay Medicare without penalty. Once your spouse stops working or you are no longer covered under their plan, you have eight months to sign up for Medicare.

What if I already have Medicare Advantage — do I still have to sign up for Part B?

No. Medicare Advantage is Part C, and it includes Part A and Part B coverage. If you are enrolled in Medicare Advantage, you already have Part A and Part B through that plan. You do not sign up for Part B separately.

How much is the Medicare penalty if I miss my enrollment window?

The Part B penalty is 10 percent of the standard monthly premium for each full year you were may be able to access but not signed up. The amount changes each year because the standard premium changes. The penalty is permanent and recalculated each January, so it grows if you delay further.

Can I sign up for Medicare anytime, or only during certain periods?

You can sign up during your initial enrollment window (eight months around your 65th birthday) without penalty. After that, you can sign up during the general enrollment period (January 1 to March 31 each year), but the penalty will explore if you do not have may have access to employer coverage. Some life events, like losing employer coverage, open a special enrollment period outside these windows.