Medicare Part A, B, C vs D: Coverage and Key Differences

Medicare consists of four parts that each provide coverage for a different type of care. Part A is usually used for hospital services, and part B is for medical and outpatient services. Medicare coverage is also available through private health plans (Part C or Medicare Advantage) and prescription drug coverage is available through Medicare Part D. It's significant to understand how these parts vary as Medicare coverage is not one-size-fits-all. 

What Are the Four Parts of Medicare?

Medicare is the federal health insurance program for people age 65 and older, and for certain younger individuals with qualifying disabilities. The program is organized into four parts, each covering a distinct category of care and each following its own enrollment, cost-sharing, and claims process. 

What Medicare Part A Covers

Part A is known as hospital insurance because it covers services received in a hospital. Covered services include:

• Inpatient hospital stays, including a semi-private room, meals, and general nursing care
• Treatment in a skilled nursing facility (SNF) after a qualifying hospital stay 
• Hospice care for patients with a terminal diagnosis
• Limited home health services, such as intermittent skilled nursing or physical therapy

Medicare Part A Costs

Most beneficiaries pay premium-free Part A as a result of having paid Medicare payroll tax for 40 quarters of covered employment or their spouse's covered employment. They charge $311 per month for 30–39 quarters and $565 per month for less than 30 quarters. The inpatient hospital deductible is $1,736 per benefit period, plus coinsurance for extended stays in the hospital or skilled nursing facility.

What Medicare Part B Covers

Part B pays for the cost of medically necessary outpatient and preventive services. This includes:

• Physician office visits and outpatient specialist care
• Preventive services, including screenings, vaccines, and annual wellness visits
• Durable medical equipment (DME), such as wheelchairs, walkers, and oxygen equipment
• Outpatient therapy, diagnostic tests, and certain mental health services

Medicare Part B Costs

The standard Part B premium is $202.90 per month, up from $185 in 2025. The deductible is $283 per year. Once the deductible has been paid, beneficiaries usually pay a 20% coinsurance on the Medicare-approved amount, with Medicare paying the remaining 80%. Depending on income, beneficiaries in the higher brackets face a surcharge on top of the monthly premium called an Income-Related Monthly Adjustment Amount (IRMAA) that may range anywhere between an extra $81.20 to $487 per month. 

Medicare Part C: Medicare Advantage

Part C, known as Medicare Advantage, is an alternative to Original Medicare offered through private insurance companies approved by Medicare. These bundled plans must cover everything Part A and Part B cover, and most also include Part D prescription drug coverage. Many Medicare Advantage plans add extra benefits not available under Original Medicare, such as dental, vision, and hearing care.

Medicare Part C Costs

Some plans and carriers may charge different prices. There are many Medicare Advantage plans with a $0 premium, and for plans that include integrated drug coverage, the average premium is estimated to be $11.50 per month. If you have a Part C plan, you will still be required to pay your Part B premium. CMS estimates that there will be approximately 5,600 Medicare Advantage plans available across the country. 

Medicare Part D: Prescription Drug Coverage

Part D covers the cost of prescription medications. Beneficiaries can sign up for a standalone Part D plan as well as Original Medicare, or they can get their drug coverage included in a Medicare Advantage plan. Private insurance companies determine coverage and drug formularies within guidelines of Medicare. 

Medicare Part D Costs

The amount that each plan will require you to pay before the deductible is met is limited to $615. Mediations paid under the plan will continue without requiring any additional out-of-pocket cost from the beneficiary after their out-of-pocket cost of drugs hits $2,100, up from $2,000 in 2025. Average standalone Part D premium is expected to drop to about $34.50/month, while average drug coverage premium bundled into Medicare Advantage is expected to drop near $11.50/month. 

Medicare Part A vs B vs C vs D: What’s the Difference And Coverage?

Although all four parts are part of Medicare, each serves a different purpose. Understanding these differences can help beneficiaries identify what type of coverage applies to hospital care, medical services, Medicare Advantage, and prescription drugs.

Medicare Part A vs Part B

• Part A: Mainly for inpatient hospital services, skilled nursing facility services, hospice care and some home health services.
• Part B: Mainly related to visits to doctors, outpatient care, preventive care, medical equipment, and other medically necessary services.
• Coverage focus: Part A is primarily for two types of care: hospital and related care, and Part B for medical and outpatient care.
• Costs: Enrollment in part A might be premium-free for those eligible; in Part B, premiums and other costs are usually required.
• Provider access: Both are components of Original Medicare and generally allow beneficiaries to use Medicare-participating providers.

Medicare Part B vs Part C

• Part B: Is part of Original Medicare and helps cover medically necessary and preventive outpatient services.
• Part C: Also called Medicare Advantage, provides Medicare-covered Part A and Part B services through Medicare-approved private health plans.
• Coverage structure: Part B is administered under Original Medicare, while Part C coverage is administered through a private Medicare Advantage plan.
• Provider networks: Part C plans may have specific provider networks, while Original Medicare generally offers broader provider access.
• Additional benefits:Some Part C plans may provide benefits other than Original Medicare, depending on the plan.
• Costs: Part C costs vary by plan and may include premiums, deductibles, copayments, and other cost-sharing.

Medicare Part C vs Part D

• Part C: Medicare Advantage provides Part A and Part B coverage through a private Medicare-approved plan.
• Part D: Provides prescription drug coverage through private Medicare-approved drug plans.
• Prescription coverage: Some Medicare Advantage plans include prescription drug coverage, while Part D can also be purchased as a standalone prescription drug plan.
• Plan structure: Part C benefits and costs differ depending on the Medicare Advantage plan; Part D plans have their own formularies, premiums, deductibles and cost-sharing.
• Primary focus: Part C is for Medicare Advantage and Part D is for prescription medications.

BillingFreedom: Where Medicare Billing Accuracy Meets Better Claims Performance

Identifying a patient as having Medicare Part A, B, C or D is not enough for Medical billing. The requirements of a payer, claims rules, and considerations for reimbursement may differ for each coverage type. BillingFreedom uses this distinction during the billing process to ensure accurate claims and minimize any unnecessary reimbursement problems for providers. 

The key performance indicators are: 

• 98%+ Clean Claim Rate - supports accurate claim preparation and submission.
• <1% Denial Rate - focuses on reducing preventable Medicare claim denials.
• 30% Average AR Reduction - supports timely follow-up on outstanding Medicare receivables.
• 25% Average Increase in Collections - reflects a focus on improving reimbursement from submitted claims.
• 98% Collections - supports consistent payment recovery across the revenue cycle.

From eligibility verification and charge entry to claim submission, denial management, payment posting, and AR follow-up, BillingFreedom’s medical billing process is structured around the coverage and payer requirements that influence Medicare reimbursement. This helps providers maintain cleaner claims while managing the administrative differences between Medicare Parts A, B, C, and D.

To learn more about our outstanding medical billing services, you may not hesitate to get in touch with us through email at info@billingfreedom.com or phone at +1 (855) 415-3472. 

Our priority is your financial peace of mind!