Medicare explained: the four parts, 2026 costs and open enrollment

The short answer: Medicare is the federal health insurance program for people 65 and older and some younger people with disabilities. It has four parts, and open enrollment runs October 15 to December 7.

• Part A: hospital stays, skilled nursing and hospice
• Part B: doctor visits, outpatient care and preventive services
• Part C (Medicare Advantage) bundles A and B; Part D covers prescriptions
• 2026 costs and how to help a parent below
• Next step: Plan it with the Household Binder ($6.99).

Medicare is the federal health insurance program for people 65 and older and for some younger people with disabilities. It can feel confusing, with its lettered parts, enrollment windows and choices between Original Medicare and Medicare Advantage. This guide explains what each part of Medicare covers, what it costs in 2026, when to sign up, and how to use the yearly open enrollment period, which runs from October 15 to December 7, to review your coverage for 2027. It is also written for adult children helping a parent sort through their options.

This page is general education, not insurance, legal or financial advice. Coverage rules vary by state and by policy, so always read your own policy documents. Medicare paperwork piles up quickly. The Household Binder has pages for insurance, doctors and prescriptions, and the Family Life Admin Bundle helps families keep a parent's important information organized.

The four parts of Medicare

Medicare.gov breaks the program into four parts:

Parts A and B together are called Original Medicare. With Original Medicare, you can see any doctor or hospital in the country that accepts Medicare, and many people add a separate Part D plan and a Medicare Supplement (Medigap) policy to help with out-of-pocket costs. Medicare Advantage plans often have provider networks and different cost-sharing, and many include extras such as dental or vision benefits.

What Medicare costs in 2026

Most people do not pay a premium for Part A, because they or a spouse paid Medicare taxes for at least 10 years while working. Part B does have a premium. According to the Centers for Medicare and Medicaid Services, the standard Part B premium is $202.90 a month in 2026, up from $185 in 2025, and the yearly Part B deductible is $283. Individuals with modified adjusted gross income above $109,000, or married couples filing jointly above $218,000, pay an extra income-related monthly adjustment amount.

On top of premiums, you will usually have deductibles, copays and coinsurance. Under Original Medicare, after you meet the Part B deductible you generally pay 20% of the Medicare-approved amount for most doctor services, with no yearly out-of-pocket cap, which is why many people buy a Medigap policy or choose Medicare Advantage, which does have a yearly limit. Costs for 2027 are usually announced in the fall.

Medicare also doesn't pay for most long-term custodial care, such as help with bathing, dressing or eating. Our guide to long-term care insurance explains how families plan for that cost.

When to sign up for Medicare

Most people first enroll during their Initial Enrollment Period, a seven-month window that begins three months before the month you turn 65, includes your birthday month and ends three months after. If you already get Social Security benefits, you are usually enrolled in Parts A and B automatically. If you or your spouse are still working with qualifying employer coverage, you may be able to delay Part B and sign up later during a Special Enrollment Period without a late penalty. Missing your window without other coverage can lead to a lifelong late enrollment penalty, so mark the dates on the family planner. Our guide to how Social Security works explains claiming at 62, 67 or 70.

Medicare open enrollment: October 15 to December 7

Medicare.gov's enrollment page explains that during open enrollment each fall you can:

1. Switch from Original Medicare to a Medicare Advantage plan, or from Medicare Advantage back to Original Medicare.
2. Switch from one Medicare Advantage plan to another.
3. Join, switch or drop a Part D prescription drug plan.

Changes made by December 7 take effect on January 1. If you are already in a Medicare Advantage plan, there is a second chance from January 1 to March 31 to switch to another Medicare Advantage plan or return to Original Medicare.

How to review your Medicare plan each fall

1. Read the Annual Notice of Change your plan sends in September; it lists next year's costs and benefit changes.
2. Make a list of every prescription, dose and pharmacy you use.
3. List your doctors, specialists and preferred hospitals.
4. Use the Medicare Plan Finder at Medicare.gov to compare plans with your exact drugs and pharmacies.
5. Check each plan's premium, deductible, copays, yearly out-of-pocket maximum and drug tiers.
6. Confirm your doctors are in network before switching to a Medicare Advantage plan.
7. Get free one-on-one help from your local State Health Insurance Assistance Program (SHIP) if you have questions.
8. Enroll by December 7 and keep copies of your confirmation.

Protecting your Medicare information

Treat your Medicare number like a credit card number. Medicare will not call you out of the blue to ask for it or to sell you a plan. Only share it with your doctors, pharmacies, your plan and people you trust, and review your Medicare Summary Notices for services you do not recognize. If someone pressures you to switch plans quickly, hang up and call 1-800-MEDICARE yourself.

Helping a parent with Medicare

If you are helping a parent, start by gathering their Medicare card, plan cards, prescription list and doctor contacts in one place, and ask them to name you as an authorized representative so plans can talk with you. Our guide on how to organize medical records has a simple system, and our estate planning checklist covers health care directives and powers of attorney.

The bottom line

Medicare has four parts: A for hospital care, B for medical care, C for Medicare Advantage and D for drugs. In 2026 the standard Part B premium is $202.90 a month. Sign up on time when you turn 65, and use Medicare open enrollment from October 15 to December 7 each year to make sure your plan still fits your doctors, drugs and budget.