Medicare is federal health coverage mainly for people age 65 and older, and for some younger people with disabilities or certain conditions. Some people are enrolled automatically when they start Social Security benefits. Others need to sign up. Knowing which applies to you can help prevent a gap in coverage or a late-enrollment penalty.
Quick answer
Medicare has four parts: Part A covers hospital care, Part B covers doctor visits and outpatient care, Part C (Medicare Advantage) provides Parts A and B through a private plan, and Part D covers prescription drugs. Most people pay $0 a month for Part A. The standard Part B premium is $202.90 a month in 2026, before any income-based surcharge. You can choose Original Medicare, often with a separate drug plan and optional Medigap coverage, or a Medicare Advantage plan. Compare doctors, medicines, networks, and total costs before choosing. Some people are enrolled automatically; others need to sign up. Your work and health coverage can affect your deadlines, so check with Social Security before delaying Part B. Use the Medicare Plan Compare tool and contact a free SHIP counselor if you want help reviewing options.
For the full retirement decision map, including Medicare, Social Security, income, taxes, and caregiving, visit the retirement guides and calculators hub.
- What matters most
- Whether you will be enrolled automatically and your 7-month Initial Enrollment Period
- Action
- Confirm your dates and enrollment steps with Social Security
- What matters most
- Whether your plan qualifies for a Special Enrollment Period
- Action
- Confirm with your employer before delaying Part B
- What matters most
- Provider networks, out-of-area coverage, and plan rules
- Action
- Check whether your doctors and the care you may need are covered where you travel
- What matters most
- Deductibles, coinsurance, drug costs, and out-of-pocket limits
- Action
- Compare total costs and coverage, not the premium alone
- What matters most
- Original Medicare has no annual out-of-pocket limit for Part A and B services
- Action
- Review Medigap, Medicare Advantage, employer, Medicaid, and other coverage that may apply
The Four Parts
Part A: Hospital Insurance
What it covers: Inpatient hospital care, skilled nursing facility care (after qualifying hospital stay), home health care, hospice care.
What you pay: Most people pay $0/month for Part A if they or their spouse have enough Medicare-covered work. The 2026 inpatient hospital deductible is $1,736 for each benefit period. It is not an annual deductible. See CMS’s 2026 Medicare cost fact sheet.
What to know: Part A does not cover most outpatient care, regular doctor visits, or prescriptions.
Part B: Medical Insurance
What it covers: Doctor visits, outpatient care, preventive services, medical equipment, lab tests, some home health care.
What you pay: The standard 2026 Part B premium is $202.90/month. Higher income can add an income-related monthly adjustment amount (IRMAA). The annual Part B deductible is $283. After you meet it, Part B generally pays 80% of the Medicare-approved amount for covered services. You generally pay the remaining 20%. See CMS’s 2026 Medicare cost fact sheet and Medicare.gov’s current cost guidance.
What to know: Original Medicare does not have an annual out-of-pocket limit for Part A and Part B services. Medigap, employer coverage, Medicaid, or other help may reduce costs for some people. Compare eligibility and total costs before choosing coverage.
Part C: Medicare Advantage
What it is: A private insurance alternative to Original Medicare. Private insurers contract with Medicare to provide all Part A and B benefits (and usually Part D) through their own network plans.
Cost structure: Each plan sets its own premiums and cost-sharing within Medicare rules. Plans may use provider networks and may require prior authorization for some services. Some plans include extra benefits, but coverage and availability vary.
Trade-off: Provider access, referral rules, and out-of-network coverage vary by plan. Review the plan's Evidence of Coverage and check directly with providers before enrolling.
Part D: Prescription Drug Coverage
What it covers: Outpatient prescription drugs through private plans that contract with Medicare.
What you pay: Premiums and cost-sharing vary by plan, location, and prescriptions. Plans have their own formularies (drug lists), pharmacies, and coverage rules, so compare your medicines before enrolling.
What to know: Most Medicare Advantage plans include Part D; check your specific plan before adding separate drug coverage. Joining a separate Part D plan can make you leave your current Medicare Advantage plan, depending on its type. With Original Medicare, you can add a separate Part D plan if you need drug coverage. Other creditable drug coverage can affect that decision. Read Medicare’s drug-coverage choices and plan-type rules before enrolling.
- A late Part B enrollment penalty may apply if you miss a deadline and do not qualify for an exception. The penalty generally continues while you have Part B. Confirm dates and employer-coverage rules with Social Security.
- The federal Medigap Open Enrollment Period generally lasts six months beginning when you are 65 or older and enrolled in Part B. Guaranteed-issue rights and enrollment protections can also depend on your circumstances and state. [Medicare.gov explains the timing and exceptions](https://www.medicare.gov/health-drug-plans/medigap/ready-to-buy/when).
- For 2026 Medicare premiums, the income used for IRMAA generally comes from a tax return filed two years earlier. See our [2026 IRMAA guide](/learn/2026-irmaa-brackets) and Social Security's current rules.
Enrollment Periods
Initial Enrollment Period (IEP): A 7-month window around your 65th birthday: the 3 months before your birthday month, your birthday month, and the 3 months after. Many people who already receive Social Security are enrolled automatically. If you are not enrolled automatically, check your dates and sign-up steps with Social Security.
Special Enrollment Period (SEP): Some people can delay Part B without a penalty while they or their spouse have qualifying group health coverage based on current employment. Employer size and other details can affect which coverage pays first, so confirm your situation with the employer and Social Security. The SEP is generally eight months from when employment or qualifying coverage ends, whichever happens first. Retiree coverage and COBRA generally are not current-employment coverage for this purpose.
General Enrollment Period (GEP): If you missed your Initial Enrollment Period and do not qualify for a Special Enrollment Period, you can sign up for Part B from January 1 through March 31. Coverage generally starts the month after you sign up. A late-enrollment penalty may apply. Confirm your start date with Social Security.
Yearly plan-change periods: Medicare Open Enrollment runs from October 15 through December 7. You can review and change Medicare Advantage or Part D coverage for the next year. If you are already in a Medicare Advantage plan, the Medicare Advantage Open Enrollment Period runs from January 1 through March 31 and allows certain plan changes. The choices available depend on your current coverage; see Medicare's current enrollment rules.
Original Medicare vs. Medicare Advantage
- Original Medicare (Parts A and B; optional Medigap and Part D)
- You can use any doctor or hospital that takes Medicare in the U.S.; check whether providers accept Medicare patients.
- Medicare Advantage
- For non-emergency care, you may need network providers in the plan's service area. Rules vary by plan.
- Original Medicare (Parts A and B; optional Medigap and Part D)
- No yearly limit for Part A and B services unless you have supplemental coverage such as Medigap, Medicaid, or employer/retiree coverage.
- Medicare Advantage
- Plans have a yearly limit for covered Medicare services; some plans use separate in-network and out-of-network limits.
- Original Medicare (Parts A and B; optional Medigap and Part D)
- You can join a separate Part D plan.
- Medicare Advantage
- Most plans include Part D, but check the plan details.
- Original Medicare (Parts A and B; optional Medigap and Part D)
- You may be able to buy Medigap; enrollment rights and underwriting depend on your timing and situation.
- Medicare Advantage
- You generally cannot use Medigap to cover Medicare Advantage cost sharing.
- Original Medicare (Parts A and B; optional Medigap and Part D)
- Referrals and prior authorization are less common for Original Medicare-covered services.
- Medicare Advantage
- Some plans require referrals or prior authorization for certain services.
- Original Medicare (Parts A and B; optional Medigap and Part D)
- Original Medicare does not cover some routine services, such as most dental and vision care.
- Medicare Advantage
- A plan may offer extra benefits; what is covered varies.
Neither option is best for everyone. Compare the doctors and hospitals you use, prescriptions, travel needs, premiums, deductibles, provider rules, prior authorization, and the plan's out-of-pocket limit. Read the plan documents and confirm coverage with the plan and providers before enrolling. Medicare's comparison guide describes the trade-offs.
Budgeting for What Medicare Doesn't Cover
A Medicare premium is only one part of a health-care budget. Include deductibles, coinsurance, prescription costs, supplemental or employer coverage, and services Medicare does not cover. Original Medicare has no annual out-of-pocket limit for Part A and B services unless you have other coverage. A Medicare Advantage plan has a yearly limit for covered services; its terms vary. Use the healthcare cost in retirement calculator as an estimate, and check its inputs and exclusions before relying on the result.
Long-term care is a separate planning question
Medicare does not pay for most ongoing custodial care, such as help with bathing, dressing, or other daily activities. It may cover certain short-term skilled nursing or home-health services when Medicare's conditions are met. Medicaid, private insurance, personal resources, and state rules may affect other care options. Review Medicare's long-term-care coverage and the Eldercare Locator before estimating care costs.
Check help with Medicare costs
Medicare Savings Programs can help eligible people pay premiums and other Medicare costs. Extra Help can reduce Part D prescription costs. Their income and resource rules differ; do not assume the income used for an IRMAA surcharge decides eligibility for cost help.
Start with Medicare’s cost-help programs or Social Security’s Extra Help instructions. A free SHIP counselor can help you review the applicable program and documents. An agency decides eligibility; this guide does not calculate an award.
For taxes and Medicare together, use the retirement planner and replace its sample inputs. Montgomery County, Maryland residents can also use the local financial guide for official tax-credit and bill-help contacts.
What to Do Now
Sources
2026 Medicare cost figures are from the Centers for Medicare & Medicaid Services 2026 fact sheet. For current enrollment periods and costs, use Medicare.gov, Social Security's sign-up guidance, and Social Security's Part B late-enrollment penalty guidance. For plan comparison, use Medicare Plan Compare or contact your State Health Insurance Assistance Program.
Original Medicare does not cover most long-term custodial care. Read Medicare's long-term-care coverage information before estimating nursing-home or in-home care costs. Rules and amounts can change; verify them with the responsible agency before acting.
Frequently Asked Questions
What are the four parts of Medicare?
How much does Medicare cost in 2026?
What happens if I miss my Medicare enrollment window?
Should I choose Original Medicare or Medicare Advantage?
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