Understanding Medicare: A Complete Overview
Medicare can feel overwhelming, but it doesn’t have to be. This guide breaks the program down into plain language so you can understand your coverage options and make confident decisions about your healthcare.
In short: Medicare is federal health insurance for people 65 and older, as well as certain younger people with disabilities. It is organized into four parts — A, B, C, and D — and most people combine those parts (often with a Medigap supplement) to build coverage that fits their health and budget.
A Brief History of Medicare
Medicare was signed into law in 1965 to provide healthcare coverage to Americans aged 65 and older. Today it also covers younger individuals with qualifying disabilities and people with end-stage renal disease (ESRD) or ALS.
The original program included Part A (hospital insurance) and Part B (medical insurance). Two more parts were added later: Part C (Medicare Advantage) and Part D (prescription drug coverage). Together, these four parts make up the Medicare program you know today, now covering nearly 70 million Americans.
The Four Parts of Medicare at a Glance
Part A
Part B
Part C
Part D
Original Medicare = Part A + Part B (often paired with a Part D drug plan and a Medigap supplement).
Medicare Advantage = Part C, a private plan that bundles A, B, and usually D into one plan.
Medicare Eligibility & Enrollment
When can you enroll?
Your Initial Enrollment Period (IEP) is a 7-month window: it begins three months before the month you turn 65, includes your birthday month, and ends three months after. Enrolling early helps you avoid gaps in coverage and late penalties.
A quick quirk worth knowing: if your birthday falls on the 1st of the month, your coverage can start the month before you turn 65.
If you miss your IEP and don’t have other creditable coverage, you may have to wait for the General Enrollment Period (January 1 – March 31) and could face a lifelong late-enrollment penalty.
How to apply
You can apply for Medicare and Social Security benefits at ssa.gov. If you’re already receiving Social Security, enrollment in Parts A and B is usually automatic.
Key enrollment periods at a glance
- Initial Enrollment Period (IEP): The 7 months around your 65th birthday.
- General Enrollment Period: January 1 – March 31 (for those who missed their IEP).
- Open Enrollment (Annual Election Period): October 15 – December 7. Anyone with Medicare can change Part C and Part D coverage.
- Medicare Advantage Open Enrollment: January 1 – March 31. Those already in a Medicare Advantage plan can switch plans or return to Original Medicare.
- Special Enrollment Period (SEP): Triggered by qualifying life events, such as losing employer coverage. Timing depends on the event.
Medicare Part A: Hospital Insurance
Part A covers the care you receive as an admitted hospital patient and related services.
Covers:
- Inpatient Hospital Stays
- Skilled nursing facility care (following a qualifying hospital stay)
- Home health care
- Hospice care
2026 Costs:
- Premium: $0 for most people with 10+ years (40 quarters) of Medicare-covered work history. Those with fewer quarters pay up to $565/month.
- Hospital deductible: $1,736 per benefit period (not per year — a benefit period resets after 60 days out of inpatient care).
- Hospital coinsurance: $0 for days 1–60; $434/day for days 61–90; $868/day for lifetime reserve days.
- Skilled nursing coinsurance: $0 for days 1–20; $217/day for days 21–100.
Medicare Part B: Medical Insurance
Part B covers the day-to-day medical care you receive as an outpatient.
Covers:
- Doctor visits, outpatient care, lab tests, and preventive services
- Durable medical equipment
- Mental health and therapy services
- Telehealth and diagnostic testing
2026 Costs:
- Standard premium: $202.90/month (higher earners pay more based on income).
- Annual deductible: $283.
- Coinsurance: Medicare pays 80% of the approved amount for most covered services; you’re responsible for the remaining 20% unless you have supplemental coverage.
Medicare Part C: Medicare Advantage
Medicare Advantage (Part C) is an all-in-one alternative to Original Medicare. Offered by private companies approved by Medicare, these plans bundle your Part A and Part B coverage and often add extras like dental, vision, hearing, and prescription drugs (Part D).
2026 Costs:
- You continue to pay your Part B premium, plus any premium the plan charges (many plans charge $0 beyond the Part B premium).
- Plans often have lower out-of-pocket costs than Original Medicare, but network and referral rules apply.
- Unlike Original Medicare, Medicare Advantage plans include an annual out-of-pocket maximum that caps your spending on covered services.
Medicare Part D: Prescription Drug Coverage
Part D helps cover the cost of prescription medications. You can get it as a standalone plan (added to Original Medicare) or built into a Medicare Advantage plan.
Covers:
- Both brand-name and generic prescription medications
- A $35-per-month cap on covered insulin
- Many recommended vaccines at no cost
How Part D works in 2026:
As of January 1, 2025, the old “donut hole” coverage gap was eliminated. Part D now follows a simpler structure:
- Deductible phase: You pay 100% of your drug costs until you meet your plan’s deductible (no more than $615 in 2026).
- Initial coverage phase: You pay copays or coinsurance (typically around 25%) for covered drugs.
- Catastrophic phase: Once your out-of-pocket spending reaches $2,100, you pay $0 for covered drugs for the rest of the calendar year.
You can also opt into the Medicare Prescription Payment Plan to spread your out-of-pocket drug costs into predictable monthly installments instead of paying large amounts at the pharmacy counter.
Medigap (Medicare Supplement Insurance)
Medigap plans help pay the out-of-pocket costs Original Medicare leaves behind, such as deductibles, coinsurance, and copayments. There are 10 standardized plans, labeled A, B, C, D, F, G, K, L, M, and N. Because they’re standardized, a Plan G from one company offers the same core benefits as a Plan G from another — the main difference is price and service.
Popular plans:
¹ Plans F and G also offer a high-deductible option. You first pay a higher annual deductible (set by Medicare each year); once that deductible is met, the plan pays 100% of covered services for the rest of the calendar year. High-deductible Plan G does not cover the Medicare Part B deductible, but your payments toward the Part B deductible do count toward meeting the high plan deductible on Plans F and G.
² Plans K and L pay 100% of covered services for the rest of the calendar year once you reach the annual out-of-pocket limit.
Next Steps
Use our MedicareMall Quote Finder to compare plans and prices in your area. Our team is here to guide you through every part of your Medicare journey — helping you find peace of mind and long-term savings.