Your Guide to Medicare in 2025

By Theresa Taylor | January 7, 2025

Medicare.gov website

Medicare is a federal health insurance program for people age 65 or older. People younger than age 65 with certain disabilities, permanent kidney failure, or ALS, also known as Lou Gehrig’s disease, may also be eligible for Medicare. The program helps with the cost of healthcare, but it doesn’t cover all medical expenses or the cost of most long-term care. And you have choices for how you get Medicare coverage.

Ready to start your journey to health insurance coverage with Medicare? Here are answers to commonly-asked Medicare questions.

Contents

What are the parts of Medicare?

What’s the difference between Original Medicare and Medicare Advantage?

Original Medicare vs. Medicare Advantage

What exactly do Parts A & B cover?

What ISN’T covered by Parts A & B?

What are the different kinds of Medicare Advantage Plans?

What is Medigap/Supplemental Insurance?

When do I need to sign up for Medicare?

How can I be automatically enrolled in Medicare?

What if I don’t sign up for Medicare during my Initial Enrollment Period?

Can I delay enrolling in Medicare?

When will my Medicare coverage begin after I enroll?

Key dates

What are the parts of Medicare?

Part A

Also known as Hospital Insurance, Part A helps cover:

  • Inpatient care in hospitals
  • Skilled nursing facility care
  • Hospice care
  • Home health care

You’ll receive Part A automatically if you or your spouse have worked for at least 10 years (40 quarters). For most people, the monthly premium is $0. If you don’t meet the work history requirement, the Part A premium starts at $518. There’s also a benefit period deductible of $1,676. After that, additional costs for inpatient care depend on the length of stay.

Part B

Also known as Medical Insurance, Part B helps cover:

  • Services from doctors and other health care providers
  • Outpatient care
  • Home health care
  • Durable medical equipment (like wheelchairs, walkers, hospital beds, and other equipment)
  • Many preventive services (like screenings, shots or vaccines, and yearly “Wellness” visits)

The monthly premium for Part B is income-based and is $185 in 2025 for individuals with an income of $106,000 or less. The deductible is $257, and once it’s met, you’ll pay 20% of all costs. There’s no maximum out-of-pocket limit under Part B.

Part C

Also known as a Medicare Advantage Plan (MAPD), Part C is a private, federally-regulated insurance option that covers hospital and medical costs.

MAPD/Part C plans typically have a $0 premium, with your Part B premium deducted from your Social Security benefits. A major advantage of MAPD plans is the Maximum Out-of-Pocket (MOOP) limit, which protects you from large, unexpected healthcare costs that Original Medicare does not cover. These plans often include benefits like dental, vision, hearing, fitness memberships (e.g., Silver Sneakers), prescriptions, and more.

Part D

Also known as Drug Coverage, Part D helps cover the cost of prescription drugs (including many recommended shots or vaccines). Plans that offer Medicare drug coverage are run by private insurance companies that follow rules set by Medicare. Part D premiums may vary and can increase based on your income.

What’s the difference between Original Medicare and Medicare Advantage?

When you first sign up for Medicare, and during certain times of the year, you can choose how you get your Medicare coverage. Here are the two main ways to get Medicare:

Original Medicare (Parts A, B, and/or D)

  • Original Medicare includes Part A (Hospital Insurance) with the option to include Part B (Medical Insurance).
  • You can join a separate Medicare drug plan to get Medicare drug coverage (Part D).
  • You can use any doctor or hospital that takes Medicare, anywhere in the U.S.
  • You can also buy supplemental coverage that helps pay your out-of-pocket costs (like your 20% coinsurance).

Medicare Advantage (Part C)

  • Medicare Advantage (Part C) is a Medicare-approved plan from a private company that offers an alternative to Original Medicare for your health and drug coverage. These plans bundle your Part A, Part B, and usually Part D together.
  • In many cases, you can only use doctors in the plan’s network.
  • In many cases, you may need to get approval from your plan before it covers certain drugs or services.
  • Plans often have different out-of-pocket costs than Original Medicare or supplemental coverage like Medigap. You may also have an additional premium.
  • Plans may offer some extra benefits that Original Medicare doesn’t.

Original Medicare vs. Medicare Advantage

Doctors and Hospitals

Original Medicare

Medicare Advantage
You can use any doctor or hospital that takes Medicare, anywhere in the U.S. In many cases, you can only use doctors and other providers who are in the plan’s network and service area (for non-emergency care). Some plans offer non-emergency coverage out of network, but typically at a higher cost.
In most cases, you don’t need a referral to use a specialist. You may need to get a referral to use a specialist.

Cost

Original Medicare

Medicare Advantage
For Part B-covered services, you usually pay 20% of the Medicare-approved amount after you meet your deductible. This amount is called your coinsurance. Out-of-pocket costs vary. Plans may have different out-of-pocket costs for certain services.
You pay the monthly premium for Part B. If you choose to join a Medicare drug plan, you’ll pay a separate premium for your Medicare drug coverage (Part D). You pay the monthly Part B premium and may also have to pay the plan’s premium. Some plans may have a $0 premium and may help pay all or part of your Part B premium. Most plans include Medicare drug coverage (Part D).
There’s no yearly limit on what you pay out of pocket, unless you have supplemental coverage—like Medicare Supplement Insurance (Medigap), Medicaid, employer, retiree, or union coverage. Plans have a yearly limit on what you pay for covered Part A and Part B services (with different limits for in-network and out-of-network services). Once you reach your plan’s limit, you’ll pay nothing for covered services for the rest of the year.
You can choose to buy Medigap to help pay your out-of-pocket costs that Medicare doesn’t cover (like your 20% coinsurance). Or, you can use coverage from a current or former employer or union, or Medicaid. You can’t buy Medigap to cover your out-of-pocket costs.

Coverage

Original Medicare

Medicare Advantage
Original Medicare covers most medically necessary services and supplies in hospitals, doctors’ offices, and other health care facilities. Original Medicare doesn’t cover some services, like routine physical exams, eye exams, and most dental care. Plans must cover all medically necessary services that Original Medicare covers. For some services, plans may use their own coverage criteria to determine medical necessity. Plans may also offer some extra benefits that Original Medicare doesn’t cover.
In most cases, you don’t need approval (prior authorization) for Original Medicare to cover your services or supplies. In many cases, you may need to get approval (prior authorization) from your plan before it covers certain services or supplies.
You can join a separate Medicare drug plan to get Medicare drug coverage (Part D). Medicare drug coverage (Part D) is included with most plans. In most types of Medicare Advantage Plans, you can’t join a separate Medicare drug plan.

Foreign Travel

Original Medicare

Medicare Advantage
Original Medicare generally doesn’t cover medical care outside the U.S. You may be able to buy a Medicare Supplement Insurance (Medigap) policy that covers emergency care outside the U.S. Plans generally don’t cover medical care outside the U.S. Some plans may offer an extra benefit that covers emergency and urgently needed services when traveling outside the U.S.

What exactly will Medicare Parts A and B cover?

Part A covers:

  • Blood
  • Home health services
  • Hospice care
  • Inpatient hospital care
  • Religious non-medical health care institution (inpatient care)
  • Skilled nursing facility care

Part B covers:

  • Abdominal Aortic Aneurysm Screening
  • Ambulance Services
  • Blood
  • Bone Mass Measurement (Bone Density)
  • Cardiac Rehabilitation
  • Cardiovascular Screenings
  • Chiropractic Services (limited)
  • Clinical Laboratory Services
  • Clinical Research Studies
  • Colorectal Cancer Screenings
  • Defibrillator (Implantable Automatic)
  • Diabetes Screenings
  • Diabetes Self-Management Training
  • Diabetes Supplies
  • Doctor Services
  • Durable Medical Equipment (like walkers)
  • EKG Screening
  • Emergency Department Services
  • Eyeglasses (limited)
  • Federally-Qualified Health Center Services
  • Flu shots
  • Foot Exams and Treatment (Diabetes-related)
  • Glaucoma Tests
  • Hearing and Balance Exams
  • Hepatitis B Shots
  • HIV Screening
  • Home Health Services
  • Kidney Dialysis Services and Supplies
  • Kidney Disease Education Services
  • Mammograms (screening)
  • Medical Nutrition Therapy Services
  • Mental Health Care (outpatient)
  • Non-doctor Services
  • Occupational Therapy
  • Outpatient Medical and Surgical Services and Supplies
  • Pap Tests and Pelvic Exams (includes clinical breast exam)
  • Physical Exams
  • Physical Therapy
  • Pneumococcal Shot
  • Prescription Drugs (limited)
  • Prostate Cancer Screenings
  • Prosthetic/Orthotic Items
  • Pulmonary Rehabilitation
  • Rural Health Clinic Services
  • Second Surgical Opinions
  • Smoking Cessation (counseling to stop smoking)
  • Speech-Language Pathology Services
  • Surgical Dressing Services
  • Telehealth
  • Tests (other than lab tests)
  • Transplants and Immunosuppressive Drugs
  • Travel
  • Urgently needed care
  • Virtual check-ins
  • “Welcome to Medicare” preventive visit
  • Yearly “Wellness” visit

What ISN’T covered by Part A and Part B?

Medicare doesn’t cover everything. If you need certain services Part A or Part B doesn’t cover, you’ll have to pay for them yourself unless:

  • You have other coverage (including Medicaid) to cover the costs.
  • You’re in a Medicare Advantage Plan or Medicare Cost Plan that covers these services. Medicare Advantage Plans and Medicare Cost Plans may cover some extra benefits, like fitness programs and vision, hearing, and dental services.

Some of the items and services that Original Medicare does not cover include:

  • Eye exams (for prescription eyeglasses)
  • Long-term care
  • Cosmetic surgery
  • Massage therapy
  • Routine physical exams
  • Hearing aids and exams for fitting them
  • Concierge care (also called concierge medicine, retainer-based medicine, boutique medicine, platinum practice, or direct care)
  • Covered items or services you get from a doctor or other provider that has opted out of participating in Medicare (except in the case of an emergency or urgent need)
  • Most dental care: In most cases, Original Medicare doesn’t cover dental services like routine cleanings, fillings, tooth extractions, or items like dentures. However, in some cases, Original Medicare may pay for some dental services closely related to certain covered services like:
    • A heart valve repair or replacement.
    • An organ transplant.
    • Cancer-related treatments.

What are the different kinds of Medicare Advantage Plans?

  • Health Maintenance Organization (HMO) Plan
  • HMO Point-of-Service (HMOPOS) Plan — May let you get some services out of network for a higher copayment or coinsurance.
  • Medical Savings Account (MSA) Plan
  • Preferred Provider Organization (PPO) Plan
  • Private Fee-for-Service (PFFS) Plan
  • Special Needs Plan (SNP)

What is Medigap/Supplemental Insurance?

Medigap plans help cover the costs that Original Medicare (Parts A & B) doesn’t pay, like co-payments, coinsurance, and deductibles. These plans are offered by private insurers, and premiums can vary. Medigap benefits are standardized across insurers, and you’ll pay the Part B premium of $185. After meeting a calendar-year deductible of $257 (for 2025), Medigap covers the remaining costs with no co-pays or out-of-pocket expenses. However, Medigap plans do not cover dental, vision, hearing, or gym memberships.

When do I need to sign up for Medicare?

We recommend that you start considering and planning your coverage at least eight months before your 65th birthday.

The first time you’re able to sign up for Medicare is called your Initial Enrollment Period (IEP), or sometimes called an Initial Coverage Enrollment Period (ICEP). Your IEP will run for 7 months, including the 3 months before you turn 65, the month of your 65th birthday, and the 3 months after your birthday. For example, a person whose 65th birthday is March 12, 2025 will be able to enroll between December 12, 2024 and July 12, 2025.

If you miss your IEP, you may have to wait to sign up and pay a monthly late enrollment penalty for as long as you have Part B coverage. The penalty goes up the longer you wait. You may also have to pay a penalty if you have to pay a Part A premium, also called “Premium-Part A.”

How can I be automatically enrolled in Medicare?

If you begin receiving Social Security retirement benefits between age 62 and up to 4 months before turning 65, you will be automatically enrolled in Medicare Part A when you turn 65.

If you’re not receiving Social Security benefits or are not eligible for full Social Security retirement benefits at age 65, you will need to sign up for Medicare. If you apply for Social Security 3 months before you turn 65 or later, you can sign up for Medicare when you apply for Social Security.

You can sign up for Part A during your IEP. Your Part A coverage starts 6 months back from when you sign up or when you apply for benefits from Social Security (or the Railroad Retirement Board). Coverage can’t start earlier than the month you turned 65.

After your IEP ends, you can only sign up for Part B and premium-Part A during one of the other enrollment periods.

What if I don’t sign up for Medicare during my Initial Enrollment Period?

If you have delayed enrolling in Medicare Part B and were not covered by an employer’s group health plan, you may have to pay a 10% penalty on Part B premiums for each year you go without coverage, starting the month you’re eligible for coverage. This penalty will be applied every time you pay your premiums as long as you have Part B—possibly for the rest of your life. That means the penalty will increase the longer you wait to sign up for Part B.

Remember that you still have until three months after your 65th birthday to sign up for Part B. Avoid the penalty by enrolling for Medicare when you are able.

If you do have health insurance through your own or your spouse’s employer, you won’t be penalized for delaying enrollment. There is a Special Enrollment Period (SEP) for this scenario.

Can I delay enrolling in Medicare?

If you’re working and covered by a group health plan from your current or spouse’s employer (and the employer has 20+ employees), you can delay enrolling in Part B and avoid the premium penalty. You may choose to enroll only in Part A (which is automatic). For further details, speak with your employer’s benefits department and contact SSA.gov.

When will my Medicare coverage begin after I enroll?

This will depend on your plan and when you signed up, but coverage will always start on the first day of the month.

  • If you qualify for premium-free Part A, your coverage starts the month you turn 65. If your birthday is on the first of the month, your coverage starts the month before you turn 65.
  • If you have Part B (and premium-Part A), your coverage starts based on the month you sign up.
    • If you sign up before the month you turn 65, coverage starts the month you turn 65.
    • If you sign up the month you turn 65 or during the 3 months after, your coverage starts the following month.

Can I change my Medicare plan after I’ve enrolled?

Yes, during certain times of the year you can change how you are covered. You can switch from a Medicare Advantage to Original Medicare, or switch from a Medicare Advantage plan to another Medicare Advantage plan. You can also change your Medicare health or drug coverage, which would be effective the next calendar year. See the chart below to learn when you can make these changes.

Key dates for changing your coverage

January 1 New coverage begins if you made a change. If you kept your existing coverage and your plan’s costs or benefits changed, those changes also start on this date.
January 1 to March 31 If you’re in a Medicare Advantage Plan, you can change to a different Medicare Advantage Plan or switch to Original Medicare (and join a separate Medicare drug plan) once during this time. Any changes you make will be effective the first day of the month after the plan gets your request.
October 1, 2025 Start comparing your current Medicare health or drug coverage with options for 2026. You may be able to save money or get extra benefits.
October 15 to December 7  Change your Medicare health or drug coverage for 2026, if you decide to. You can join, switch or drop a Medicare Advantage Plan or Medicare drug plan, or switch to Original Medicare during this Open Enrollment Period each year.

 

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