Medicare Basics, Coverage Choices and Key Dates
Clear explanations of how Medicare works, how Medicare Advantage and Medicare Supplement compare, what each Medicare Supplement plan letter covers, when you can enroll, and what to check before you choose a plan. Written for people turning 65, people already on Medicare, and the families who help them.
What are Medicare Parts A, B, C and D?
In short: Medicare is federal health insurance for people 65 and older and for some younger people with disabilities. Part A is hospital insurance. Part B is medical insurance. Together, Parts A and B are called Original Medicare. Part C (Medicare Advantage) is a private plan option that includes Parts A and B and usually Part D. Part D is prescription drug coverage.
Hospital insurance
Helps pay for:
- Inpatient hospital stays
- Skilled nursing facility care after a qualifying hospital stay
- Hospice care
- Some home health care
What you usually pay: Most people pay no monthly premium for Part A if they or their spouse worked and paid Medicare taxes for about 10 years (40 quarters). There is a deductible for each benefit period.
Medical insurance
Helps pay for:
- Doctor visits and outpatient care
- Lab tests, X-rays and screenings
- Preventive services, such as flu shots and wellness visits
- Durable medical equipment, such as walkers and oxygen
What you usually pay: A monthly premium (higher for people with higher incomes), a yearly deductible, and usually 20% of the Medicare-approved amount after the deductible.
Medicare Advantage
Private plans approved by Medicare that provide your Part A and Part B coverage, and usually Part D drug coverage, in one plan.
- Most plans use a network of doctors and hospitals (HMO or PPO)
- Every plan has a yearly limit on what you pay for covered medical care
- Many plans include extra benefits, such as dental, vision and hearing
What you usually pay: You keep paying your Part B premium, plus any plan premium and the plan’s copays or coinsurance.
Prescription drug coverage
Drug coverage from private plans approved by Medicare. You can get it as a separate drug plan with Original Medicare, or included in most Medicare Advantage plans.
- Each plan has its own list of covered drugs (formulary) and pharmacy network
- Part D has a yearly cap on out-of-pocket costs for covered drugs
- If you go without creditable drug coverage, you may pay a late enrollment penalty for as long as you have Part D
Premiums, deductibles and the Part D cap change every year. Medicare usually announces next year’s amounts in the fall; see Medicare.gov for the current figures.
Not sure which parts you have, or what you will pay? I can review it with you at no cost.
Medicare Advantage vs. Medicare Supplement: what is the difference?
In short: Medicare Advantage replaces how you get your Original Medicare benefits with a private plan that usually has a network, lower monthly costs, copays when you get care, and a yearly out-of-pocket limit. A Medicare Supplement (Medigap) policy works alongside Original Medicare and pays some or all of your share of costs, so you usually pay a higher monthly premium but less when you get care, with any doctor in the U.S. who accepts Medicare.
| Question | Medicare Advantage (Part C) | Medicare Supplement (Medigap) |
|---|---|---|
| How it works | A private plan provides your Part A and Part B coverage. | Original Medicare pays first; the policy pays some or all of what is left. |
| Doctors and hospitals | Usually a network (HMO or PPO). Some plans require referrals. | Any doctor or hospital in the U.S. that accepts Medicare. No referrals. |
| Monthly cost | Part B premium plus the plan premium, which can be low or $0. | Part B premium plus the policy premium, which is usually higher. |
| Costs when you get care | Copays and coinsurance, such as a daily copay for a hospital stay. | Low or none, depending on the plan letter you choose. |
| Yearly out-of-pocket limit | Yes. Every plan has a maximum for covered medical care. | Original Medicare has no limit; the policy covers much or all of the gap. |
| Prescription drugs | Usually included. | Not included. You add a separate Part D plan. |
| Extra benefits | Often includes dental, vision, hearing and other extras. | Generally not included. |
| Travel | Emergencies are covered anywhere; routine care is usually limited to the plan’s area or network. | Works anywhere in the U.S. that accepts Medicare. |
| Changing later | You can change plans each year during the Annual Enrollment Period. | Outside certain protected times, most states allow the insurer to ask health questions. Rules vary by state; New York, for example, allows enrollment year-round. |
You cannot use a Medicare Supplement policy with a Medicare Advantage plan. The best choice depends on your doctors, prescriptions, health, travel and budget.
Happy with your Medicare Advantage plan but worried about hospital copays? A hospital indemnity policy can pay cash benefits for covered hospital stays.
Medicare Supplement (Medigap) plan types: what each letter covers
In short: Medicare Supplement plans are standardized and named by letter: A, B, C, D, F, G, K, L, M and N. Every plan with the same letter has the same benefits, no matter which insurance company sells it. The main differences between companies are the monthly premium, how they set and raise their prices, and their customer service.
How to read the chart: ✓ means the plan pays 100%. A percentage means the plan pays that share. A dash (—) means the plan does not cover it. On a phone, swipe sideways to see every plan.
| Benefit | A | B | C1 | D | F1,2 | G | High-Deductible G2 | K3 | L3 | M | N4 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Part A hospital coinsurance and 365 extra hospital days | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Part B coinsurance or copays | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓4 |
| Blood (first 3 pints) | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓ |
| Part A hospice care coinsurance | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓ |
| Skilled nursing facility coinsurance | — | — | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓ |
| Part A hospital deductible | — | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | 50% | ✓ |
| Part B deductible | — | — | ✓ | — | ✓ | — | — | — | — | — | — |
| Part B excess charges | — | — | — | — | ✓ | ✓ | ✓ | — | — | — | — |
| Foreign travel emergency (up to plan limits) | — | — | 80% | 80% | 80% | 80% | 80% | — | — | 80% | 80% |
| Plan deductible you pay first each year | — | — | — | — | — | — | $2,950 in 2026 | — | — | — | — |
| Yearly out-of-pocket limit | — | — | — | — | — | — | — | $8,000 in 2026 | $4,000 in 2026 | — | — |
- Plans C and F can only be bought by people who were eligible for Medicare before January 1, 2020. If you became eligible on or after that date, Plan G is the closest option.
- High-Deductible Plan G (and High-Deductible Plan F for people eligible before 2020): you pay a yearly deductible first ($2,950 in 2026), then the plan pays like regular Plan G or F for the rest of the year, usually for a much lower monthly premium.
- Plans K and L pay part of your costs until you reach the yearly out-of-pocket limit; after that, the plan pays 100% of covered services for the rest of the year.
- Plan N pays the Part B coinsurance, except for copays of up to $20 for some office visits and up to $50 for emergency room visits that do not lead to an inpatient admission. Plan N does not pay Part B excess charges.
With every plan except C and F, you pay the Part B deductible yourself ($283 in 2026). Medicare announces the 2027 amounts each fall, and this page will be updated when they are released. Medicare Supplement plans do not include prescription drug coverage, so most people also choose a separate Part D drug plan. Massachusetts, Minnesota and Wisconsin use their own plan designs.
Which plan letter fits you, and what will it cost in your ZIP code? Rafael will compare Medicare Supplement prices from the companies we represent and walk you through your best options on one free call.
The plans most people compare
The most complete plan for people new to Medicare
Pays nearly everything Original Medicare leaves to you. After you pay the Part B deductible each year, covered care usually costs you nothing more.
A lower premium in exchange for small copays
Usually costs less each month than Plan G. You pay the Part B deductible, small office and emergency room copays, and any Part B excess charges.
The lowest premium for people with savings
You pay a higher yearly deductible ($2,950 in 2026) before the plan begins paying, in exchange for a much lower monthly premium. After the deductible, it pays the same as Plan G.
A popular choice for people whose Medicare Advantage plan is ending: if your plan is leaving, you may be able to buy High-Deductible Plan G without health questions. Some people pair it with a hospital indemnity policy to help with the deductible if they are hospitalized.
About hospital indemnity ›How to find the best price on a Medicare Supplement plan
In short: Because the benefits are the same for every company that sells a given letter, comparing prices for the same plan letter is the most important step. The lowest price today is not always the best value, so also look at how each company prices its plans and how much its rates have gone up in past years.
Choose your plan letter first
Decide which letter fits your needs and budget, such as Plan G or Plan N. Then compare only that letter across companies.
Compare prices for your ZIP code
Prices depend on your ZIP code, age, sex and tobacco use. Medicare’s official Medigap policy finder shows which companies sell plans where you live. Your state’s department of insurance may also publish rate comparisons.
Ask how the company sets its prices
Community-rated: everyone pays the same price regardless of age. Issue-age-rated: the price is based on your age when you buy. Attained-age-rated: the price rises as you get older. All three can still increase because of inflation and rising health costs.
Look at rate increase history
A low starting price can rise quickly. Ask how much the company’s rates have gone up in recent years in your state.
Ask about discounts
Many companies offer a household discount when two people in the same home have a policy, and some offer a discount for paying by bank draft or yearly.
Let us compare for you
Skip the calls to multiple insurance companies. We compare Medicare Supplement prices, pricing methods and rate history from the companies we represent in your area, explain the differences in plain language, and help you apply, at no cost to you.
Get my price comparisonComparing prices on your own takes time, and the cheapest plan today is not always the best value. Let Rafael do the comparison for you and explain which company and plan make the most sense for your budget.
Health questions (underwriting): when you can buy a Medicare Supplement without them
In short: Outside of certain protected times, most insurance companies may ask health questions before selling you a Medicare Supplement plan. Based on your answers, they can decline your application or charge you more. During the protected times below, the company must sell you a plan without health questions, and it cannot charge you more because of your health.
Your Medicare Advantage plan is ending or leaving your area
If your Medicare Advantage plan leaves Medicare, stops serving your area, or you move out of its service area, you have a guaranteed right to buy certain Medicare Supplement plans without health questions. For most people this includes Plans A, B, D, G, High-Deductible G, K and L; people eligible for Medicare before 2020 can also choose Plans C and F.
Timing: you can apply as early as 60 days before your plan coverage ends and no later than 63 days after it ends. Keep the notice your plan sent you, since it shows the date your coverage ends.
Check if I qualifyYour Medigap Open Enrollment Period
A one-time, 6-month window that starts the first month you are both 65 or older and enrolled in Part B. During this time you can buy any Medicare Supplement plan sold in your state, at the best available price, with no health questions.
You tried Medicare Advantage for the first time
If you joined a Medicare Advantage plan when you first became eligible at 65, or dropped a Medicare Supplement to try Medicare Advantage for the first time, you generally have up to 12 months to return to Original Medicare and buy a supplement without health questions.
Other situations that may qualify
- Your employer or union coverage that works with Original Medicare is ending.
- Your Medicare Supplement company goes bankrupt or ends your policy through no fault of your own.
- Your plan misled you or broke the rules.
State rules: birthday rules and year-round enrollment
Some states give extra protections. For example, California has a birthday rule that gives people with a Medicare Supplement plan a window each year around their birthday to switch to a plan with the same or fewer benefits without health questions. New York allows people to buy a Medicare Supplement plan at any time of year without being turned down for health reasons. Florida, Georgia and most other states do not have a birthday rule, so outside of the protected times above, health questions usually apply. Rules change, so we confirm the current rules for your state before you apply.
Important: Do not cancel your current coverage until your new Medicare Supplement policy has been approved and you know its start date.
Is your Medicare Advantage plan ending in 2027? Your window to buy a Medicare Supplement without health questions is limited. Rafael will confirm whether you qualify, compare Plan G, High-Deductible Plan G and other options, and help you apply before your deadline.
When can I sign up for Medicare or change my plan?
In short: Most people first sign up during a 7-month Initial Enrollment Period around their 65th birthday. After that, you can change Medicare Advantage or drug plans each year from October 15 to December 7, with coverage starting January 1. Certain life events, such as losing employer coverage, moving, or a plan ending, open a Special Enrollment Period.
Initial Enrollment Period
Seven months: the 3 months before your 65th birthday month, your birthday month, and the 3 months after. Signing up in the months before your birthday month lets coverage start on time.
Employer coverage and a Special Enrollment Period
If you or your spouse have group health coverage from current employment, you may be able to delay Part B. You then get 8 months to sign up after the job or the coverage ends, whichever comes first. COBRA and retiree coverage do not count as current employment.
Check with your employer’s benefits office, because the rules depend on the size of the employer.
Annual Enrollment Period: October 15 to December 7
Join, switch or drop a Medicare Advantage or Part D plan. Changes start January 1. Review the Annual Notice of Change your plan mails each fall.
Medicare Advantage Open Enrollment, January 1 to March 31: if you are in a Medicare Advantage plan, you can make one change to another Medicare Advantage plan or to Original Medicare.
Special Enrollment Periods
You may be able to change plans outside the usual dates if you move, lose other coverage, qualify for Medicaid or Extra Help, move into or out of a nursing home, or your plan stops serving your area.
General Enrollment Period: January 1 to March 31
If you did not sign up for Part A or Part B when first eligible and do not qualify for a Special Enrollment Period, you can sign up now. Coverage starts the month after you sign up, and late enrollment penalties may apply.
Medigap Open Enrollment Period
A one-time, 6-month period that starts the first month you are 65 or older and have Part B. During this time, insurers generally cannot deny you or charge more because of your health. Some states offer additional protected times.
Where to check your deadlines
- Medicare.gov lists every enrollment period and the Special Enrollment Periods you may qualify for.
- Social Security (ssa.gov or 1-800-772-1213) handles Part A and Part B sign-up.
- Your plan’s letters: the Annual Notice of Change, or a non-renewal letter, lists the dates that apply to you.
- A licensed agent can confirm your dates and help you avoid gaps or penalties.
Not sure which enrollment period applies to you? Call and I will confirm your dates.
Checklist: what to compare before you choose a Medicare plan
In short: Before choosing a plan, confirm that your doctors and hospitals are covered, that your prescriptions are on the plan’s drug list at a price you can manage, and compare the total yearly cost, not just the monthly premium.
- List every doctor and specialist you see.
- Confirm each one is in the plan’s network for next year.
- Ask whether you need referrals to see specialists.
- Confirm your preferred hospitals are in network.
- Find the daily copay for an inpatient stay and how many days it applies.
- Check costs for outpatient surgery and emergency care.
- Write down each drug, its dose and how often you take it.
- Check that each drug is on the plan’s drug list and its tier.
- Confirm your pharmacy is preferred, and ask about mail order.
- Ask whether any drug needs prior authorization.
- Monthly plan premium, plus your Part B premium.
- Medical and drug deductibles.
- Copays for the visits and services you use most.
- The plan’s yearly out-of-pocket maximum.
- An estimate of your total cost for the year.
Also consider dental, vision and hearing needs, travel plans, and the plan’s Medicare star rating.
Bring your list of doctors and prescriptions. I will check them against the plans I offer in your area, at no cost.
Official Medicare, Social Security and Extra Help resources
These free government and nonprofit resources are the official sources for Medicare information. I recommend keeping them handy.
Medicare.gov
Official information on coverage, costs and enrollment periods. Call 1-800-MEDICARE (1-800-633-4227), 24 hours a day, 7 days a week. TTY: 1-877-486-2048.
Medicare Plan Finder
Medicare’s official tool to compare Medicare Advantage, Part D and Medigap options by ZIP code.
Sign up for Part A and Part B
Apply for Medicare, change your address, or replace your Medicare card. Call 1-800-772-1213. TTY: 1-800-325-0778.
Help paying for prescriptions
Extra Help is a federal program that lowers Part D drug costs for people with limited income and resources. Apply through Social Security.
Medicare Savings Programs
State programs that can help pay Part A and Part B premiums and, for some people, deductibles and copays. Apply through your state Medicaid office.
State Health Insurance Assistance Program (SHIP)
Free, unbiased Medicare counseling from your state’s SHIP program, such as SHINE in Florida, GeorgiaCares in Georgia and HIICAP in New York.
Prefer to have someone walk you through it? I help in English and Spanish, by phone or video.
Five common Medicare questions
Is Medicare free?
Not completely. Most people pay no monthly premium for Part A, but Part B has a monthly premium, and there are deductibles, coinsurance and copays. Medicare Advantage, Medigap and Part D plans may also have premiums. Medicare Savings Programs and Extra Help can lower costs for people with limited income.
Do I have to sign up for Medicare if I am still working at 65?
It depends on your coverage. If you or your spouse have group health coverage from current employment, you may be able to delay Part B without a penalty. If you have an HSA, contributions must stop once your Medicare coverage begins. Check with your employer’s benefits office before you decide.
What is the difference between Medicare and Medicaid?
Medicare is federal health insurance based mainly on age or disability. Medicaid is a joint federal and state program based on income and resources. Some people qualify for both and may be eligible for special Medicare Advantage plans for people with Medicare and Medicaid, called D-SNPs.
Can I change my Medicare plan if I am not happy with it?
Yes. You can change Medicare Advantage and Part D plans each year from October 15 to December 7. If you are in a Medicare Advantage plan, you can also make one change from January 1 to March 31. Special Enrollment Periods allow changes after certain life events. Switching to a Medicare Supplement may require health questions in most states.
Does it cost more to use a licensed agent?
No. My help is free, and plan premiums are the same whether you enroll with me or on your own. I compare the plans I offer in your area against your doctors, prescriptions and budget.
Have a question that is not listed here? Ask me directly.
Sources
- Medicare.gov: Parts of Medicare
- Medicare.gov: When can I join a health or drug plan?
- Medicare.gov: Special Enrollment Periods
- Medicare.gov: Medicare Savings Programs
- Medicare.gov: Compare Medigap plan benefits
- Medicare.gov: When can I buy a Medigap policy?
- Social Security: Apply for Part D Extra Help
- SHIP Technical Assistance Center
This guide is general education about Medicare. Your plan documents, Medicare.gov and Social Security decide your exact costs, coverage and dates. Reviewed by Rafael E. Mendoza, licensed insurance agent, REMCARE Insurance Agency, NPN 8929595. Last reviewed October 2, 2026.
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