Original Medicare is an essential federal health insurance program for Americans aged 65 or older as well as some for younger people with disabilities. However, navigating the various parts, enrollment periods, and plan options can be daunting. With so much to consider—from eligibility requirements to potential penalties for late enrollment—it's easy to feel overwhelmed. This step-by-step guide will help simplify the process so you can smoothly transition into Medicare and manage your coverage with confidence.

Throughout this article, we'll be referring to Original Medicare, comprised of Part A and Part B, as simply “Medicare”.

Step 1: Determine your eligibility

You generally become eligible for Medicare once you turn 65, as long as you're a United States citizen or have been a permanent resident for at least five consecutive years. That said, you can also qualify earlier in the following situations:

• Disability: You've received Social Security Disability Insurance (SSDI) benefits for at least 24 months.
• Lou Gehrig's disease: You've been diagnosed with Lou Gehrig's disease (commonly known as “ALS”) and have received SSDI benefits for the minimum amount of time, often six months.
• End-Stage Renal Disease (ESRD): You've been diagnosed with ESRD and have been on dialysis for three months or have had a kidney transplant.

Most people qualify for premium-free Part A because they or their spouse had Medicare taxes deducted from their paychecks for a total of 40 quarters (10 years of work). There is a common misconception that you cannot qualify for Medicare if you haven't worked and paid Medicare taxes for this amount of time, but that's not the case. You can still get Medicare even if you or your spouse never paid Medicare taxes, but you will have to pay a premium for Part A coverage.

Step 2: Learn About the Different Parts of Medicare

The Medicare program has two main parts. Here's a closer look at each and how they work.

Medicare Part A

Medicare Part A is hospital insurance that helps you pay for inpatient care at hospitals, skilled nursing facilities, hospice care, along with some outpatient home health care services. It's currently free for about 99% of Medicare beneficiaries¹, as they've paid Medicare taxes for at least 10 years while working. However, if you don't qualify for the premium-free Part A, your monthly cost will depend on the amount of time you or your spouse worked and paid Medicare taxes. For example, in 2025, if you or your spouse paid Medicare taxes for at least 30 quarters (7.5 years) you'll pay $285 per month for Part A, while individuals who have worked less than this will pay the full premium or $518 per month.²

Part A fast facts:

• Part A is hospital Insurance
• Typically $0 monthly premium
• $1,676 deductible per inpatient hospital benefit period for 2025
• Helps cover inpatient stays up to 150 days
• Helps cover skilled nursing facility stays up to 100 days
• Helps cover home health care and hospice care
• If you stick with Original Medicare, you can add a Medicare Supplement to help cover out-of-pocket costs³

Medicare Part B

Medicare Part B is medical insurance that helps you pay for medically necessary health care services from doctors and other health care providers. It also covers some of the costs involved with outpatient care, home health care, preventative services, and durable medical equipment.

To get coverage, you'll need to pay an income-based monthly premium⁴. For example, the premium is $185 in 2025 if you make less than or equal to $106,000 as an individual or $212,000 as a couple. However, it can go up to $628.90 per month if you make $500,000 or more as an individual or $750,000 or more as a couple.⁵

Part B fast facts:

• Part B is medical insurance
• The starting premium in 2025 is $185
• Premiums are income-based for higher-income individuals
• $257 annual deductible for 2025
• Usually 20% coinsurance on covered items and services
• Helps cover home health services
• Helps cover clinical labs⁶

Step 3: Enroll in Medicare

Before you can choose a Medicare insurance plan, you'll need to ensure you are enrolled in both Part A and Part B. In other words, you need to notify the federal government that you want to take advantage of your Part A and Part B benefits. You can do so in a few ways but will incur costs if you miss certain enrollment windows. As discussed further below, in some cases, you will be automatically enrolled in Part A and Part B. However, if you do not have premium-free Part A, you will never be automatically enrolled into it.

Initial enrollment period

If you are not automatically enrolled in Part A and Part B, your first chance to sign up for Medicare is during your Initial Enrollment Period which starts three months before the month you turn 65 and ends three months after.⁷ To enroll, you apply with the Social Security Administration (SSA) or Railroad Retirement Board (RRB), as applicable to your situation. You can do so online, over the phone, or by faxing or mailing in the completed application form.⁸ You'll need to be prepared with a few pieces of information, including your:

• Date and place of birth
• Permanent resident card if you're not a U.S. citizen
• Medicaid number and start and end dates (if applicable)
• Employment start and end dates if you have health insurance coverage through a group plan (for you or your spouse)
• Coverage start and end dates if you have health insurance coverage through a group plan⁹

The SSA or RRB will check how long you've paid Medicare taxes to determine your Part A premium, if any, and process your requests for Part A and B coverage.¹⁰ Once approved, you'll receive a welcome package with your Medicare card and number.

Note¹¹: If you've already applied for retirement or disability benefits from the SSA or RRB, your prior application serves as your Medicare application so you won't need to apply again. Once you get approved for SSA or RRB benefits, you'll automatically get Part A coverage when you're eligible for Medicare. If you've had SSA or RRB benefits for at least four months before you turn 65, you'll also be automatically enrolled in Part B. Otherwise, you will have to actively enroll in Part B.

After your Initial Enrollment Period ends, you can only sign up for Part A and Part B during one of the other enrollment periods.

General enrollment periods

If you miss your Initial Enrollment Period, you can sign up for Part A and/or Part B during the General Enrollment Period which runs from January 1st to March 31st of each year. Once signed up, your coverage will go into effect the first day of the following month. However, late enrollment penalties may apply.¹²

Special Enrollment Periods

Special Enrollment Periods are periods triggered by certain qualifying events that allow you to sign up for Medicare premium-Part A and Part B without any penalties. For example, you may qualify for one if you lose your current creditable health care coverage, move out of your plan's service area, or miss your Initial Enrollment Period because you are impacted by a declared national disaster.¹⁴ You can get a full list of qualifying life events for premium-Part A and Part B here. The start dates, end dates, and durations of Special Enrollment Periods vary based on the triggering event.

Anytime for premium-free Part A¹⁵

If you qualify for premium-free Part A you will generally be automatically enrolled on your 65th birthday. If you choose to delay your part A or do not qualify for automatic enrollment on your 65th birthday, you can still sign up for Part A anytime after you turn 65. Your Part A coverage will be backdated six months from your application date or when you applied for SSA/RRB (as applicable) benefits — as long as it's after your 65th birthday or date of eligibility.

Medicare enrollment summary

Step 4: Decide how you want to receive your medicare coverage

Once you've enrolled in Medicare Part A & Part B, you can choose to how you want to receive your coverage and if you want to add to your coverage with one or more of the following Medicare insurance plans:

• Medicare Advantage: Medicare Advantage plans, also known as Medicare Part C, offer an alternative way to get Medicare through a private Medicare-approved insurance company. The plans include Part A, B, and often D, along with extra benefits that Original Medicare does not offer such as routine dental, routine vision, hearing, transportation, and more.
• Medicare Supplement Plan: If you opt for Original Medicare, you can apply for a Medicare Supplement Plan (Medigap) to help pay some of the remaining health care costs for covered services and supplies, like copayments, coinsurance, and deductibles not paid by Original Medicare.
• Prescription Drug Plan: Prescription drug coverage, also known as Medicare Part D, is a private insurance plan that helps to cover the cost of prescription drugs. You can add it to Original Medicare as a stand-alone Prescription Drug Plan (PDP) or choose a Medicare Advantage plan that includes it.¹⁶

Compare the key differences between Original Medicare with Medicare Supplement and Medicare Advantage plans.

Deciding between Original Medicare and a Medicare Advantage plan can be difficult because there are a wide range of factors to consider. Additionally, every Medicare Advantage plan is a bit different so you'll need to shop around to look for good fits in your area and then compare them to Original Medicare. Our Medicare Supplement vs Medicare Advantage guide can help you understand the options, and make the right decision.

If you have any questions or would like guidance from someone with a deep understanding of the different Medicare insurance plans, you can schedule a time to chat with one of our licensed insurance agents. They'll talk you through the details of the various plan types and help you figure out which is best for your unique needs.

Step 5: Review your Medicare plan annually

Once you decide on a Medicare insurance plan and enroll, you'll be set for a year. However, you should be aware of the two annual open enrollment periods:

• Annual Enrollment Period (October 15th to December 7th):¹⁷ During this enrollment period you can:
  • Join, drop, or switch to another Medicare Advantage plan with or without drug coverage (or add or drop drug coverage).
  • Switch from Original Medicare to a Medicare Advantage plan or from a Medicare Advantage plan to Original Medicare.
  • Join, drop, or switch to another PDP if you're in Original Medicare.

• Medicare Advantage Open Enrollment Period (January 1st to March 31st):¹⁸ During this enrollment period, if you are already enrolled in a Medicare Advantage plan, you can:
  • Switch to another Medicare Advantage plan with or without drug coverage
  • Drop your Medicare Advantage plan and return to Original Medicare. You'll also be able to join a separate PDP.

When the enrollment periods roll around, you'll want to review your current plan and consider if it's still the best fit for your needs. Not only can your plan and the other plans on the market change each year, but your medical circumstances and health needs can also shift. You may find, for example, that your plan wasn't great for the services you actually ended up using throughout the year. Perhaps you paid more in out-of-pocket expenses or more for premiums than you'd like. No matter the case, the enrollment periods are a good time to check in and assess your situation. Here are some questions you can ask yourself:

• How much did you spend on health care over the past year? Add up your premiums, deductibles, copays, and other out-of-pocket costs. Are they in line with what you hoped to spend? Could another plan or plan type be more cost-effective?
• Is your plan changing? Plan providers can issue an Annual Notice of Change (ANOC). If your plan is changing, check how it will impact your costs and coverage. In today's market, drug coverage and drug formularies are changing year-over-year, making the need to conduct a review of your plan that much more important.
• Have your health care needs changed? Have you developed or do you foresee developing any new health conditions that will require more frequent care? Will your plan cover the services and medications you need at a competitive price?
• Did you have any trouble accessing care? Consider how easy it was to see your doctors and if any referrals, approvals, or network limitations caused delays in your care.
• Were you satisfied with the quality of care you received? Reflect on your overall experience with the providers and facilities covered by your plan.
• Did extra plan benefits help you save money or did you wish you had them? Consider the pros and cons of extra benefits on Medicare Advantage plans like routine dental, routine vision, and transportation. Did you spend more than you needed to because you didn't have these benefits?
• Would you like professional guidance? If you'd like help in your annual evaluations, an InsureMe licensed agent can review your current plan and usage to help you decide.

Switching plans during these enrollment periods tends to be relatively easy. If you're on a Medicare Advantage plan and want to switch to Original Medicare, you'll need to contact your current insurance company directly to request a disenrollment. From there, contact Medicare at 1-800-MEDICARE and request to enroll into Original Medicare. If you want to switch from Original Medicare to Medicare Advantage, you'll need to find the Medicare Advantage plan you want and follow the provider's enrollment process.¹⁹ An InsureMe licensed insurance agent can help you navigate this process, so that you're not stuck doing it all on your own.

Common Medicare questions and answers

Do I automatically get Medicare when I turn 65?

You'll typically need to enroll to get Medicare when you turn 65 but there are a few exceptions. Generally, if you qualify for premium-free Part A, you'll automatically be enrolled in Medicare Part A when you turn 65 if you've already applied and been approved for retirement or disability benefits from the SSA or RRB. Further, you'll generally automatically be enrolled in Part B if you've had SSA or RRB benefits for at least four months before your 65th birthday.

What if I miss my initial enrollment period?

If you miss your Initial Enrollment Period, you can still enroll in Medicare but may face late enrollment penalties on your Part A and/or Part B premium (depending on how late your enrollment is), unless you qualify for a Special Enrollment Period.

What if I miss the open enrollment period?

Unless you qualify for a Special Enrollment period, if you miss the Open Enrollment period but want to make Medicare plan changes, you'll need to wait until the following year.

What's the penalty for late enrollment?

The Medicare late enrollment penalties vary between Part A and Part B. If you're late to sign up for premium Part A coverage, you'll generally owe a 10% penalty for twice the amount of time you've delayed getting coverage. If you're late to sign up for Part B, you'll generally owe 10% per year you delayed coverage for as long as you have coverage.

Can I switch between Medicare plans?

Yes, you can switch from Original Medicare to Medicare Advantage and back. Additionally, you can switch between different Medicare Advantage plans. However, unless you qualify for a Special Enrollment Period, plan changes can only be made during the designated annual open enrollment periods (as applicable).

What if you or your spouse is still working and you have health insurance coverage when you become eligible for Medicare?

If you have qualified group health insurance coverage during your Initial Enrollment Period, you can delay enrollment until that coverage terminates without being subject to a penalty. When the group health plan coverage or employment ends, whichever happens first, you'll qualify for an eight-month Special Enrollment Period. Note that COBRA isn't considered a group health plan coverage so won't impact the date a Special Enrollment Period starts and ends.²⁰

Is Medicare free after 65?

Turning 65 means you're eligible for Medicare coverage but the coverage won't necessarily be free. Medicare Part A is premium-free if you or your spouse paid Medicare taxes for a total of at least 10 years while working. However, Medicare Part B generally comes with a monthly premium, which varies depending on your income. You will also generally be responsible for deductibles, copays, and coinsurance. If you opt to enroll into a Medicare Supplement plan, or a Part D Prescription Drug Plan, you'll pay additional premiums for those. There are some Medicare Part C Medicare Advantage plans, which are an alternative to Original Medicare parts A and B, and often also include your Medicare Prescription Drug coverage. Some Medicare Advantage plans offer what's called a Part B Giveback where a portion of, or even all of, your Part B premium is reimbursed.

Enroll in Medicare with peace of mind

Medicare is a vital program that helps millions of Americans access affordable health care after they hang their working hats. As your eligibility for the program approaches, it's important to understand the enrollment windows to avoid late enrollment penalties. Additionally, you'll need to weigh the various plan options so you can find the best fit for your situation and needs.

If you have any questions or want to consult on your Medicare insurance plan options, you can book a time to chat with a friendly member of InsureMe's team of licensed insurance agents. Their top priority is helping you get the care you need at a competitive price that suits your budget and health care needs.