Understanding the difference between Medicare Part A and Part B is one of the most important steps in navigating your Medicare coverage. Together, these two parts form Original Medicare, the foundation of federal health insurance for Americans 65 and older. But each part covers very different services, has its own costs, and carries separate enrollment rules.
In this guide, we break down exactly what Part A and Part B cover, what they cost in 2026, how to enroll, and what happens if you sign up late. Whether you’re turning 65 or helping a parent understand their options, this guide gives you the clarity you need to make confident Medicare decisions.
What Is Medicare Part A (Hospital Insurance)?
Medicare Part A is often called hospital insurance because it primarily covers inpatient care. If you need to be admitted to a hospital, Part A is the portion of Medicare that helps pay for that stay.
What Does Part A Cover?
Part A covers four main categories of care:
- Inpatient hospital stays — Semi-private rooms, meals, nursing services, medications administered during your stay, and other hospital services
- Skilled nursing facility (SNF) care — Up to 100 days of skilled care following a qualifying 3-day hospital stay
- Hospice care — Comfort care for terminally ill patients, including pain management, counseling, and respite care for caregivers
- Home health care — Part-time skilled nursing care, physical therapy, and other services when you are homebound
Important: Part A does not cover long-term custodial care (help with daily activities like bathing and dressing), most outpatient services, or prescription drugs you take at home.
2026 Part A Costs
Here are the official Part A cost figures for 2026, as published by the Centers for Medicare & Medicaid Services (CMS):
| Cost Type | 2026 Amount |
|---|---|
| Monthly premium | $0 for most people (with 40+ quarters of work history); $311/mo with 30-39 quarters; $565/mo with fewer than 30 quarters |
| Inpatient hospital deductible | $1,736 per benefit period |
| Hospital coinsurance (days 61-90) | $434 per day |
| Lifetime reserve days (days 91-150) | $868 per day |
| Skilled nursing facility coinsurance (days 21-100) | $217 per day |
Approximately 99% of Medicare beneficiaries qualify for premium-free Part A because they (or their spouse) paid Medicare taxes for at least 10 years (40 quarters).
What Is Medicare Part B (Medical Insurance)?
Medicare Part B is your medical insurance. While Part A handles inpatient hospital care, Part B covers the doctors, outpatient services, and preventive care you use day to day.
What Does Part B Cover?
Part B covers a wide range of medically necessary and preventive services:
- Doctor and specialist visits — Office visits, consultations, and second opinions
- Outpatient hospital services — Same-day surgery, emergency room visits, and observation stays
- Preventive services — Annual wellness visits, flu shots, mammograms, colonoscopies, diabetes screenings, and other covered preventive care (many at no cost to you)
- Durable medical equipment (DME) — Wheelchairs, walkers, hospital beds, oxygen equipment, and other medically necessary equipment
- Ambulance services — When medically necessary transportation is required
- Mental health services — Outpatient therapy, psychiatric evaluations, and counseling
- Lab tests and diagnostic imaging — Blood work, X-rays, MRIs, CT scans, and other diagnostic tests
Important: Part B does not cover most dental care, vision exams for glasses, hearing aids, or routine foot care. These are common gaps that Medicare Advantage or Medigap plans may help address.
2026 Part B Costs
| Cost Type | 2026 Amount |
|---|---|
| Standard monthly premium | $202.90 (higher for incomes above $106,000 single / $212,000 married filing jointly) |
| Annual deductible | $283 |
| Coinsurance | 20% of the Medicare-approved amount after deductible |
Unlike Part A, everyone pays a Part B premium, and there is no cap on out-of-pocket spending under Original Medicare. This is one reason many beneficiaries choose to add supplemental coverage like a Medicare Supplement (Medigap) plan.
For a complete look at all 2026 Medicare premiums, including IRMAA income brackets and cost comparison scenarios, see our Medicare Premiums and Costs for 2026: Complete Breakdown.
Medicare Part A vs. Part B: Side-by-Side ComparisonHere is a quick-reference comparison of the two parts of Original Medicare:
| Feature | Part A (Hospital Insurance) | Part B (Medical Insurance) |
|---|---|---|
| What it covers | Inpatient hospital stays, SNF care, hospice, home health | Doctor visits, outpatient care, preventive services, DME, ambulance |
| 2026 Premium | $0 for most; up to $565/mo without enough work history | $202.90/mo standard (income-adjusted) |
| 2026 Deductible | $1,736 per benefit period | $283 per year |
| Coinsurance | $434/day (days 61-90); $868/day (lifetime reserve days) | 20% of Medicare-approved amount |
| Out-of-pocket maximum | No cap under Original Medicare | No cap under Original Medicare |
| Enrollment | Usually automatic if receiving Social Security at 65 | Usually automatic; opt-in if not receiving Social Security |
| Late enrollment penalty | 10% premium surcharge for 2x the years you could have enrolled | 10% surcharge per year you delayed, for life |
Medicare Enrollment Periods: When to Sign Up
Knowing how and when to enroll in Medicare is critical. Missing your enrollment window can mean gaps in coverage and permanent penalties.
Initial Enrollment Period (IEP)
Your IEP is a 7-month window centered around the month you turn 65:
- Starts 3 months before your 65th birthday month
- Includes your birthday month
- Ends 3 months after your birthday month
This is the best time to enroll. If you are already receiving Social Security benefits, you may be enrolled in Parts A and B automatically.
General Enrollment Period (GEP)
If you missed your IEP, you can sign up during the General Enrollment Period from January 1 through March 31 each year. Coverage begins on July 1 of that year, and you may face late enrollment penalties.
Special Enrollment Period (SEP)
If you delayed Medicare because you (or your spouse) had employer-based health coverage, you qualify for a Special Enrollment Period. You can enroll:
- Anytime while you are still covered by the employer plan
- Within 8 months of losing that employer coverage or stopping work (whichever comes first)
Enrolling during a SEP protects you from late enrollment penalties. Learn more about Medicare enrollment periods and key deadlines.
Late Enrollment Penalties: What They Cost
Signing up late for Medicare Part A or Part B can result in permanent premium increases. Understanding these penalties can save you thousands of dollars over your lifetime.
Part A Late Enrollment Penalty
If you do not qualify for premium-free Part A and fail to enroll when first eligible, your premium may increase by 10%. You will pay this higher premium for twice the number of years you could have enrolled but did not.
Example: If you were eligible for Part A for 2 years but did not sign up, you would pay a 10% higher premium for 4 years.
Part B Late Enrollment Penalty
The Part B penalty is more severe and lasts for as long as you have Part B. Your monthly premium increases by 10% for each full 12-month period you could have been enrolled but were not.
Example: If you delayed Part B enrollment for 3 years without qualifying coverage, your 2026 premium would be 30% higher: $202.90 + $60.87 = $263.77 per month, every month, for life.
The only way to avoid these penalties is to enroll during your IEP or qualify for a Special Enrollment Period through employer coverage.
How Parts C and D Complete Your Medicare Coverage
Original Medicare (Parts A and B) provides essential coverage, but it does not cover everything. Two additional parts can help fill the gaps:
Medicare Part C (Medicare Advantage)
Medicare Part C, also known as Medicare Advantage, is an alternative way to receive your Medicare benefits through private insurance companies approved by Medicare. These plans:
- Combine Part A and Part B coverage into one plan
- Often include Part D (prescription drug) coverage
- May offer extra benefits like dental, vision, hearing, and fitness programs
- Typically use provider networks (HMO, PPO)
- Include an annual out-of-pocket maximum, which Original Medicare does not have
Medicare Part D (Prescription Drug Coverage)
Part D helps cover the cost of prescription drugs. Key points for 2026:
- Available through private insurance companies as a standalone plan (with Original Medicare) or included in Medicare Advantage
- Premiums, formularies, and copays vary by plan
- In 2026, the annual out-of-pocket cap for Part D drugs is $2,100
- A late enrollment penalty applies if you go 63+ consecutive days without creditable drug coverage
Choosing the Right Coverage: Original Medicare vs. Medicare Advantage
Once you have Parts A and B, you face an important decision: stay with Original Medicare (and potentially add a Medigap plan and Part D plan) or switch to a Medicare Advantage plan that bundles everything together.
Each path has trade-offs:
- Original Medicare + Medigap + Part D: Maximum provider flexibility (see any doctor who accepts Medicare), predictable costs with Medigap covering deductibles and coinsurance, but higher monthly premiums
- Medicare Advantage: Lower premiums, extra benefits, out-of-pocket cap, but network restrictions and prior authorization requirements
The right choice depends on your health needs, budget, preferred doctors, and prescription medications. Learn more about Medicare Advantage vs. Medigap to compare your options.
Who Is Eligible for Medicare Part A and Part B?
Most people become eligible for Medicare when they turn 65. You may also qualify if you:
- Are under 65 with certain disabilities and have received Social Security Disability Insurance (SSDI) for 24 months
- Have End-Stage Renal Disease (ESRD) or Amyotrophic Lateral Sclerosis (ALS)
To qualify for premium-free Part A, you (or your spouse) must have worked and paid Medicare taxes for at least 10 years (40 quarters). Everyone who is eligible for Part A can also enroll in Part B.
Frequently Asked Questions
Is Medicare Part A free?
For most people, yes. Approximately 99% of beneficiaries qualify for premium-free Part A because they or their spouse paid Medicare taxes for at least 10 years. If you do not have enough work history, you can purchase Part A for $311 or $565 per month in 2026.
Can I have Part A without Part B?
Yes. You can enroll in Part A only. However, if you want to purchase Part A (because you do not qualify for it for free), you must also enroll in Part B. Most people benefit from having both parts of Original Medicare.
What is the Part B deductible for 2026?
The annual Part B deductible for 2026 is $283. After meeting this deductible, you typically pay 20% of the Medicare-approved amount for covered services.
Do I need both Part A and Part B?
While not technically required, having both parts ensures comprehensive coverage. Part A alone leaves you without coverage for doctor visits, outpatient care, and preventive services. Most Medicare beneficiaries enroll in both. Read more about what Medicare covers to understand the full picture.
What does Medicare Part B not cover?
Part B does not cover most dental care, routine eye exams for glasses, hearing aids, long-term care, or cosmetic surgery. For these services, you may want to explore Medicare Advantage plans that offer supplemental benefits.
How do I avoid Medicare late enrollment penalties?
Enroll during your Initial Enrollment Period (the 7-month window around your 65th birthday) or qualify for a Special Enrollment Period through employer coverage. If you miss these windows, you may face permanent premium surcharges on both Part A and Part B.
Get Expert Help With Your Medicare Decisions
Choosing the right Medicare coverage is one of the most important financial and healthcare decisions you will make. With over 20 years of Medicare expertise, Karl Bruns-Kyler and The Big 65 team are licensed in 33 states and provide free, personalized guidance to help you understand your options and find the coverage that fits your needs.
Whether you are approaching 65, already on Medicare, or helping a loved one navigate their choices, we are here to help you make sense of it all. Contact The Big 65 to get started with a no-obligation consultation.