Medicare Explained: Your Complete 2026 Guide

What Is Medicare and Who Qualifies for It?

Medicare is a federal health insurance program established in 1965 under Title XVIII of the Social Security Act. According to the CMS Medicare and You 2026 handbook, over 67 million Americans were enrolled as of 2026. Medicare is administered by the Centers for Medicare & Medicaid Services (CMS), a federal agency within the Department of Health and Human Services. Applications are processed by the Social Security Administration (SSA), a separate agency, which is why you apply at ssa.gov — not medicare.gov.

Who qualifies for Medicare?

You qualify for Medicare under one of four conditions. First: you are age 65 or older and a U.S. citizen or a lawful permanent resident who has continuously resided in the United States for at least five consecutive years. Second: you are under 65 and have received Social Security Disability Insurance (SSDI) benefits for at least 24 months. Third: you have End-Stage Renal Disease (ESRD — permanent kidney failure requiring dialysis or a transplant) at any age. Fourth: you have been diagnosed with Amyotrophic Lateral Sclerosis (ALS, also called Lou Gehrig's disease), in which case Medicare coverage begins immediately with your first month of SSDI eligibility, with no 24-month waiting period.

Does your work history affect your Medicare eligibility?

Your work history does not affect your eligibility for Medicare, but it determines your Part A premium. If you or your spouse paid Medicare taxes for at least 40 quarters — meaning 10 years of Medicare-covered employment — you receive premium-free Part A. If you paid taxes for 30 to 39 quarters, your 2026 Part A premium is $278 per month. Fewer than 30 quarters means the premium is $505 per month. Part B has a premium regardless of work history. Your Social Security statement at ssa.gov/myaccount shows your Medicare credits. Understanding how Medicare fits into your broader retirement planning is the first step in choosing the right coverage.

Now that you know who qualifies, we will look at exactly what each part of Medicare covers — because the part structure is what determines both your monthly costs and the decisions you will need to make at retirement.

What Are the Four Parts of Medicare and What Does Each Cover?

Medicare is divided into four parts — A, B, C, and D — each covering a distinct category of care. Parts A and B form Original Medicare, the government-administered baseline program. Part C (Medicare Advantage) is a private-sector alternative that replaces Parts A and B. Part D adds prescription drug coverage. Understanding all four is essential before making any coverage decision. Here is what the Centers for Medicare & Medicaid Services official website says each one covers:

What does Part A specifically cover and exclude?

Part A covers four categories of care. Inpatient hospital care means any stay where a doctor formally admits you with a written order — not just an overnight stay. The Part A deductible of $1,736 applies per benefit period (not per year), so if you are hospitalized, recover, and then return to the hospital more than 60 days later, the deductible resets. Days 1 through 60 have no daily coinsurance beyond the deductible. Days 61 through 90 cost $434 per day in coinsurance. Beyond 90 days, you draw on 60 lifetime reserve days at $868 per day. Skilled nursing facility (SNF) care is covered at $0 for days 1 through 20, then $217.50 per day for days 21 through 100, after a qualifying hospital stay of at least 3 days. Part A does not cover long-term custodial care (help with bathing, dressing, or eating). Our detailed guide on what Medicare Part A and B cover walks through every benefit category. For end-of-life care, see our guide on Medicare hospice care rules and costs.

What does Part B specifically cover and exclude?

Part B covers two categories: medically necessary services (services or supplies that are needed to diagnose or treat your medical condition) and preventive services (screenings, vaccines, and annual wellness visits). After you meet the $283 annual deductible, Part B pays 80% of the Medicare-approved amount for covered services and you pay 20% — with no annual cap on your out-of-pocket liability. This 20% coinsurance with no cap is a significant financial exposure. Preventive services covered at no cost to you include the annual wellness visit, cardiovascular disease screenings, colorectal cancer screenings, mammograms, and influenza and pneumococcal vaccines. Original Medicare does not cover routine dental, routine vision exams, hearing aids, or custodial care. For more on coverage gaps, read our full guide on whether Medicare covers dental, vision, and hearing and our detailed article on Medicare dental coverage rules.

How does Part D work and what is the $2,100 cap?

Part D, the prescription drug benefit, was created by the Medicare Prescription Drug, Improvement, and Modernization Act of 2003. Plans operate with a formulary — a list of covered drugs divided into tiers, with generic drugs at the lowest cost tier and specialty drugs at the highest. The Inflation Reduction Act of 2022 made a transformative change: beginning in 2025 and continuing in 2026, there is a hard $2,100 annual cap on your out-of-pocket drug costs for covered drugs. This eliminates the previous coverage gap (colloquially known as the "donut hole") for most beneficiaries. Once you spend $2,100 out of pocket in a plan year, your plan pays 100% of covered drug costs for the rest of the year. For a full breakdown, see what Medicare Part D covers or use our Medicare Donut Hole & Coverage Gap Calculator to model your drug costs. You can also evaluate standalone drug plans alongside Advantage plans using our Medicare Part C vs. Part D decision guide.

Now that you understand what each part covers, the most urgent question is timing: when do you need to enroll, and what happens if you do not?

When Do I Need to Enroll in Medicare and What Are the Deadlines?

According to the SSA Publication 10043 — Medicare, Medicare enrollment is governed by specific time-limited windows. Missing the right window without qualifying coverage triggers permanent, lifetime penalty surcharges. There are five enrollment periods you need to know: the Initial Enrollment Period, the Special Enrollment Period, the General Enrollment Period, the Annual Enrollment Period, and the Medicare Advantage Open Enrollment Period.

What is the Initial Enrollment Period (IEP)?

Your Initial Enrollment Period (IEP) is your primary, personal Medicare signup window. It is exactly 7 months long — it begins 3 months before the month you turn 65, includes your birthday month, and ends 3 months after. The timing of when you enroll within this window determines when your coverage starts. If you enroll during the first 3 months (before your birthday month), coverage begins on the first day of your birthday month. If you enroll during your birthday month or the following 3 months, coverage is delayed by 1 to 3 months. For the complete breakdown of every enrollment period with dates and calculations, see our full Medicare enrollment periods guide.

What is the Special Enrollment Period (SEP) and who qualifies?

The Special Enrollment Period is an 8-month window that begins the month after your active employment or group health coverage ends — whichever comes first. You qualify for an SEP only if you or your spouse were actively employed at a company with 20 or more employees, and your health insurance was based on that active employment. The critical details most people miss: COBRA continuation coverage does not qualify as active employer coverage. Retiree health insurance does not qualify. A marketplace (ACA) plan does not qualify. Only current employer-sponsored group coverage from an employer with 20 or more employees protects you. To use the SEP, you submit Form CMS-40B (Medicare enrollment application) along with Form CMS-L564 (Request for Employment Information, completed by your employer). For step-by-step application instructions, read our how to enroll in Medicare guide and our overview of the Medicare and You 2026 handbook.

What is the late enrollment penalty?

If you miss your IEP or let your SEP expire without enrolling, you face permanent, lifetime premium penalties. For Part B: the penalty is 10% of the standard monthly premium for every full 12-month period you went without Part B and without qualifying employer coverage. In 2026, a 24-month delay (2 full penalty periods) adds $40.58 to your monthly Part B premium — permanently. You pay this surcharge for as long as you have Medicare. Read our full guide on the Medicare Part B late enrollment penalty to learn how to appeal or avoid it. For Part D: the penalty is calculated at 1% of the national base beneficiary premium ($36.78 in 2026) multiplied by the number of full uncovered months. A 24-month delay adds $8.83 to your monthly Part D premium — permanently. Use our Medicare Part B Late Enrollment Penalty Calculator and our Medicare Part D Late Enrollment Penalty Calculator to see your exact penalty amounts.

Enrollment sets the foundation. Your next decision — and one that affects your healthcare costs for the rest of your retirement — is which coverage path to choose: Original Medicare or Medicare Advantage.

What Is the Difference Between Original Medicare and Medicare Advantage?

Original Medicare (Parts A and B) is a fee-for-service program run directly by the federal government through CMS. You can see any provider in the United States that accepts Medicare with no network restrictions, no referrals required, and no prior authorization for most services. Medicare Advantage (Part C) is an alternative delivery system — private health plans (typically HMOs or PPOs) approved and paid by CMS to deliver Medicare benefits. According to the CMS Medicare Advantage program statistics, over 33 million people — roughly half of all Medicare beneficiaries — were enrolled in Advantage plans as of 2026. Read our full guide on what Medicare Part C is to learn how HMO and PPO networks operate.

Where does Original Medicare leave you exposed?

Original Medicare has no annual out-of-pocket limit. If you have a serious illness requiring multiple hospitalizations and extensive outpatient treatment, your cumulative costs can reach tens of thousands of dollars in a single year. The 20% Part B coinsurance applies without a cap. To protect against this, most Original Medicare enrollees also purchase a Medicare Supplement Insurance plan (Medigap) and a stand-alone Part D drug plan. Medigap Plan G is the most popular in 2026 — it covers the $1,736 Part A deductible, the 20% Part B coinsurance, and Part B excess charges, leaving only the $283 Part B annual deductible as your exposure. Our Medicare supplement plans guide compares all lettered Medigap plans. Use our Medigap Plan Comparison Tool to see which plan fits your situation.

What are the trade-offs of Medicare Advantage?

Medicare Advantage plans often feature low or $0 monthly premiums, bundled drug coverage, and extra benefits like dental, vision, and gym memberships. However, they come with important restrictions. You must use the plan's network of doctors and hospitals — out-of-network care is either not covered or covered at higher cost. Most HMO plans require a referral from a primary care doctor to see a specialist. In 2026, the maximum in-network out-of-pocket limit is $9,350. Many plans are structured as HMOs or PPOs with step therapy requirements and prior authorization requirements for expensive procedures. If you travel frequently, have complex health needs, or prefer provider choice over managed care, Original Medicare may serve you better. Our Medicare vs. Medicare Advantage guide, the Medicare Advantage Comparison Tool, and the Medicare Advantage vs. Original Medicare Cost Checker give you the complete side-by-side comparison.

What is Medigap and when should I buy it?

Medigap (Medicare Supplement Insurance) is standardized private insurance that pays after Medicare — covering the Part A deductible, Part B coinsurance, and similar gaps. Plans are lettered A through N and must offer identical benefits within the same letter regardless of the insurer. The golden window for buying Medigap is your 6-month Medigap Open Enrollment Period, which begins the month you turn 65 and enroll in Part B. During this window, federal law (42 U.S.C. § 1395ss) guarantees your right to buy any Medigap plan in your state without medical underwriting — meaning insurers cannot deny you coverage or charge more because of health conditions. After this window closes, most states allow insurers to reject applicants or charge higher premiums based on health history. For a plan-by-plan comparison, use our Medigap Plan Comparison Tool. For a deeper look at the Advantage vs. Medigap decision, read our Medigap vs. Medicare Advantage guide.

Whether you choose Original Medicare plus Medigap or Medicare Advantage, the next thing you need to understand are the actual dollar figures — premiums, deductibles, and the income-based surcharges that affect higher-income retirees.

What Does Medicare Cost in 2026?

Per the CMS 2026 Medicare Parts A and B Premiums and Deductibles Fact Sheet, the standard monthly Medicare costs in 2026 are as follows. Part A has no premium for most enrollees who worked 40+ quarters and a $1,736 deductible per benefit period. Part B has a standard premium of $202.90 per month with a $283 annual deductible and 20% coinsurance. Part D plan premiums vary widely, with an annual out-of-pocket cap of $2,100. Higher-income beneficiaries pay the Income-Related Monthly Adjustment Amount (IRMAA) surcharge on top of Part B and Part D premiums.

What is the IRMAA surcharge?

The Income-Related Monthly Adjustment Amount (IRMAA) is an additional premium surcharge applied to higher-income Medicare beneficiaries under 42 U.S.C. § 1395r. SSA uses your Modified Adjusted Gross Income (MAGI) from two years prior. In 2026, IRMAA is triggered for individuals with 2024 MAGI above $106,000 and for married couples filing jointly with 2024 MAGI above $212,000. At the highest income tier — above $500,000 individual/$750,000 couple — the total Part B premium reaches $628.90 per month per person. IRMAA also applies to Part D, adding up to $84.70 per month at the highest tier. If your income has dropped significantly due to retirement, divorce, death of a spouse, or another qualifying life-changing event, you can request a reduction using Form SSA-44. Read our detailed guide on the Medicare IRMAA surcharge explained, use our Medicare IRMAA Calculator and MAGI for Medicare Calculator to see your exact surcharge, generate an appeal letter with our IRMAA Appeal Letter Generator, and check your appeal eligibility with our Should I Appeal My IRMAA? decision tool.

Can I get help paying my Medicare premiums?

Yes. Medicare Savings Programs (MSPs) help low-income Medicare beneficiaries pay their Part A and Part B premiums, deductibles, and cost-sharing. These are state-administered programs funded jointly by state and federal Medicaid budgets. The four levels of assistance are QMB (Qualified Medicare Beneficiary — pays Part A and Part B premiums, deductibles, and cost-sharing), SLMB (Specified Low-Income Medicare Beneficiary — pays Part B premium only), QI (Qualifying Individual — pays Part B premium, limited enrollment), and QDWI (Qualified Disabled and Working Individuals — pays Part A premium). Eligibility is based on monthly income and resource limits that vary by state. You apply through your state Medicaid agency. Our Medicare Savings Programs Estimator lets you check your eligibility. For the full eligibility guide, read our Medicare Savings Programs guide and check low-income drug subsidies with our Extra Help Eligibility Calculator.

Understanding costs also means understanding what Medicare does not cover — and how your situation changes if you are still working at 65.

What Do I Do About Medicare If I Am Still Working at 65?

If you are still employed at 65 and covered by an active employer group health plan, you have real choices — and real risks. According to CMS Coordination of Benefits rules, whether your employer plan or Medicare pays first depends on the size of your employer.

What if my employer has 20 or more employees?

If your employer has 20 or more employees, your group health plan is the primary payer and Medicare is secondary when you turn 65. This means you can delay enrolling in Part B without penalty as long as you remain employed and covered. You must enroll in Part B within 8 months of the month your active employment or group coverage ends — this is your Special Enrollment Period. You must obtain Form CMS-L564 signed by your employer as proof of coverage. Do not wait for the General Enrollment Period after your employment ends — that would result in a permanent penalty. Even while delaying Part B, many people still enroll in Part A (which is free for most people) as secondary coverage for hospital stays. We walk through every scenario in detail in our article on how to enroll in Medicare and our guide to having Medicare and private insurance at the same time.

What if my employer has fewer than 20 employees?

If your employer has fewer than 20 employees, Medicare becomes the primary payer at age 65 even if you are still working. Your employer plan becomes secondary. In this case, you must enroll in Medicare Parts A and B during your Initial Enrollment Period. Failure to do so means your employer plan may refuse to pay for services that Medicare would have covered as primary — leaving you with large unexpected bills. If you work for a small employer, review your group plan's coordination of benefits rules carefully and enroll in Medicare during your IEP regardless of whether you plan to continue working.

What about COBRA and retiree health insurance?

This is where we see the most expensive mistakes. COBRA continuation coverage is not active employer coverage and does not protect you from Medicare late enrollment penalties. If you leave your job at 65, elect COBRA, and delay Medicare Part B under the assumption that COBRA qualifies, you will accumulate a permanent penalty every 12 months you wait. Retiree health insurance from a former employer also does not count as qualifying coverage for avoiding Part B penalties. If you are on COBRA or retiree insurance when you turn 65, treat your Initial Enrollment Period as your hard deadline for Medicare enrollment. Your Medicare coverage will become primary and COBRA can serve as secondary supplemental coverage — or you can drop it. The same coordination rules apply when comparing Medicare and marketplace coverage through the Medicare vs. Obamacare guide.

With the core Medicare structure and enrollment rules in place, we will explore dual eligibility for lower-income beneficiaries who qualify for both Medicare and Medicaid.

Can I Have Both Medicare and Medicaid at the Same Time?

Yes. People who qualify for both Medicare and Medicaid are called dual eligible beneficiaries. According to the Kaiser Family Foundation Medicare and Medicaid Issue Brief, approximately 12.5 million Americans — roughly 18% of all Medicare beneficiaries — qualify for both programs as of 2026. If you are dual eligible, Medicaid helps pay for your Medicare costs, dramatically reducing your out-of-pocket spending.

How does dual eligibility work in practice?

When you have both Medicare and Medicaid, Medicare pays first as primary insurance for any service it covers. Medicaid then acts as a payer of last resort, covering cost-sharing that Medicare leaves behind — including your Part B deductible, 20% coinsurance, and in some cases your monthly premiums. Which costs Medicaid covers depends on which Medicare Savings Program tier you qualify for. Medicaid also covers services that Medicare does not, such as long-term nursing home care (after spending down assets), personal care services, and transportation to medical appointments. The rules for dual eligibility differ significantly between Medicare and Medicaid. Our guide to having Medicare and Medicaid at the same time and our deeper article on dual eligible Medicare and Medicaid beneficiaries walk through every scenario.

What is the difference between Medicare and Medicaid?

Medicare is a federal program with uniform national eligibility rules — you qualify at 65 (or with disability) regardless of your income or assets. Medicaid is a joint federal-state program with eligibility based on income and assets, and each state sets its own additional rules within federal minimum standards. Medicare covers acute care (hospital stays, doctor visits, surgery) while Medicaid covers long-term care (nursing homes, home-based personal care). For a full side-by-side comparison, read our Medicare vs. Medicaid guide or our state-specific Medicare vs. Medi-Cal in California guide.

Below you will find answers to the questions seniors ask most often about Medicare — each one complete and self-contained.

Official Sources We Used in This Guide

Every factual claim in this guide links directly to its primary government source. We do not use news articles, secondary content websites, or insurance company materials as sources.

Seniors Audit is an independent educational platform. We are not affiliated with, endorsed by, or connected to any government agency, insurance company, or financial services firm. Every statistic and regulation cited in this guide links directly to its official government source above. We have no financial interest in any coverage or enrollment decision you make.

Everything We Cover About Medicare — Full Guide Directory

Every Medicare guide, calculator, and tool on Seniors Audit is listed below, organized by topic. This is the complete map of the Medicare resource library.

Medicare Basics and Eligibility

• Medicare and You 2026 — The Official Handbook Explained — A plain-English breakdown of the entire 2026 CMS Medicare and You handbook, organized by chapter, for seniors who want the full picture in one place.
• What Does Medicare Part A and B Cover? — A line-by-line breakdown of every service covered and excluded under Part A hospital insurance and Part B medical insurance, with 2026 cost-sharing figures.
• What Is Medicare Part C (Medicare Advantage)? — Complete explanation of Medicare Advantage HMO and PPO plans, network rules, extra benefits, and the 2026 out-of-pocket maximum of $9,350.
• What Is Medicare Part D Prescription Drug Coverage? — Plain-English guide to Part D plans, formularies, the Inflation Reduction Act $2,100 out-of-pocket cap, and the late enrollment penalty for going without drug coverage.
• What Is CMS (Centers for Medicare and Medicaid Services)? — For seniors who want to understand the federal agency behind Medicare, how CMS differs from SSA, and who to contact for different types of help.

Medicare Enrollment and Deadlines

• How to Enroll in Medicare: Step-by-Step Guide — Complete walkthrough of the ssa.gov online application, documents required, automatic enrollment rules, and the automatic enrollment trap that causes surprise premium deductions.
• Medicare Enrollment Periods: IEP, SEP, GEP, AEP Explained — Official dates and rules for all five enrollment windows, with penalty calculations for each and the 2024 GEP rule change that ended the 6-month coverage gap.
• Medicare Part B Late Enrollment Penalty — How the permanent 10% per 12-month penalty is calculated, who is exempt, and the four ways to reduce or eliminate your penalty exposure.

Medicare Plan Comparison and Supplement Coverage

• Medicare vs. Medicare Advantage: Which Is Better? — Head-to-head cost and coverage comparison of Original Medicare plus Medigap versus Medicare Advantage, including 2026 out-of-pocket projections for different health scenarios.
• Medicare Supplement Plans (Medigap) Explained — Side-by-side comparison of all standardized Medigap plans A through N, what each covers, 2026 average premiums, and when to buy to guarantee acceptance.
• Medigap vs. Medicare Advantage: Which Fills Your Gaps Better? — A practical decision guide comparing Medigap and Medicare Advantage out-of-pocket costs, provider flexibility, and the key trade-offs for different retirement situations.
• Medicare Part C vs. Part D: What Is the Difference? — Clear explanation of how Part C (Medicare Advantage) and Part D (prescription drugs) relate to each other and how they work together or separately.

Medicare Costs, Premiums, and IRMAA

• Medicare IRMAA Surcharge Explained — How the Income-Related Monthly Adjustment Amount is calculated, which 2026 income brackets trigger it, and the exact process for appealing using Form SSA-44.
• Medicare Savings Programs: Complete Eligibility Guide — Full guide to the four Medicare Savings Programs (QMB, SLMB, QI, QDWI) that help low-income seniors pay Medicare premiums and cost-sharing, including how to apply in your state.

Medicare Coverage — What Is and Is Not Covered

• Does Medicare Cover Dental, Vision, and Hearing? — Exactly what Original Medicare covers and does not cover for routine dental, vision exams, eyeglasses, hearing aids, and your alternatives for filling these gaps.
• Does Medicare Cover Dental Care? — Detailed breakdown of dental coverage under Part A, Part B, and Medicare Advantage, with specific CPT codes for covered versus excluded dental procedures.
• Medicare and Hospice Care — How Medicare Part A covers hospice care, the election criteria, what is included, and what out-of-pocket costs remain for hospice patients and families.
• Can I Have Medicare and Private Insurance at the Same Time? — How coordination of benefits works when you have Medicare plus employer coverage, retiree insurance, marketplace plans, or a Veterans Affairs plan.

Medicare and Medicaid — Dual Eligibility

• Medicare vs. Medicaid: Key Differences Explained — Side-by-side breakdown of eligibility rules, coverage scope, income and asset rules, administration, and how the two programs interact.
• Can You Have Medicare and Medicaid at the Same Time? — How dual eligibility works in practice, which program pays first, and how Medicaid fills gaps in Medicare coverage for low-income beneficiaries.
• Dual Eligible Medicare and Medicaid Beneficiaries — In-depth guide to the special benefits and plan options available specifically to people who qualify for both Medicare and Medicaid.
• Medicare vs. Medicaid in California — State-specific comparison of how Medicare and Medi-Cal (California's Medicaid program) work together, including California's expanded income limits and benefits.

Related Programs — Medicare and ACA

• Medicare vs. Obamacare (ACA Marketplace) — Who should use Medicare versus a marketplace plan, coordination rules when you turn 65, and what happens to your ACA subsidies when Medicare kicks in.

Free Medicare Calculators and Tools

• Medicare Enrollment Deadline Calculator — Calculate your exact 7-month Initial Enrollment Period window and upcoming Medicare signup deadlines. The fastest way to know when you need to act.
• Medicare Effective Date Calculator — Find the exact date your Part A and Part B coverage begins based on when you sign up during your enrollment window.
• Medicare Part B Late Enrollment Penalty Calculator — Calculate your permanent Part B penalty using the official CMS formula. Essential for anyone who delayed Medicare enrollment.
• Medicare Part D Late Enrollment Penalty Calculator — Calculate your permanent prescription drug plan late enrollment penalty based on months without creditable coverage.
• Medicare IRMAA Calculator — Estimate your Part B and Part D IRMAA surcharges based on your 2024 modified adjusted gross income. Uses the official 2026 CMS income brackets.
• MAGI for Medicare Calculator — Calculate your Modified Adjusted Gross Income specifically for Medicare IRMAA and savings program thresholds.
• Medicare Premium Calculator — Calculate your total combined monthly Medicare cost including Part A, Part B, Part D, Medigap, and IRMAA surcharges.
• Medicare Savings Programs Estimator — Check whether your income qualifies you for a Medicare Savings Program that can pay your Part B premium and reduce your cost-sharing.
• Medicare Donut Hole & Coverage Gap Calculator — Model your out-of-pocket prescription drug costs under the 2026 Part D $2,100 cap and see when you cross the threshold.
• Medicare Advantage Comparison Tool — Compare Medicare Advantage plan features, drug coverage, network types, and out-of-pocket maximums side by side.
• Medicare Advantage vs. Original Medicare Cost Checker — Compare expected total annual out-of-pocket costs between Original Medicare plus Medigap versus Medicare Advantage based on your health needs.
• Medigap Plan Comparison Tool — Side-by-side comparison of standardized Medigap plans to identify which plan covers the most for your expected healthcare use.
• IRMAA Appeal Letter Generator (Form SSA-44) — Generate a customized IRMAA appeal letter and pre-filled Form SSA-44 guidance after a qualifying life-changing income event.
• Should I Appeal My IRMAA? Decision Tool — Answer five questions to see if your income drop qualifies as a Life-Changing Event under Social Security rules and whether an appeal is worth pursuing.
• Extra Help (Low Income Subsidy) Eligibility Calculator — Check whether you qualify for the federal Extra Help program that pays Part D premiums, deductibles, and copayments for low-income beneficiaries.

Related Topic Guides — Social Security, Taxes, and Retirement

• Social Security Hub — Complete Benefits Guide — Medicare and Social Security are administered together at age 65. Understand how your benefit amount is calculated, when to claim, and how Social Security affects your Medicare premiums.
• Retirement Planning Hub — Medicare is one piece of your retirement financial picture. Our retirement hub covers RMDs, IRA withdrawals, Roth conversions, and retirement tax planning alongside Medicare costs.
• Medicaid Hub — Eligibility, Benefits, and Long-Term Care — For Medicare beneficiaries who may also qualify for Medicaid due to income or long-term care needs, our Medicaid hub covers every eligibility rule and benefit category.
• Universal Senior Benefits Screener — A single tool that checks your eligibility for Medicare savings programs, Extra Help, SNAP, LIHEAP, and other federal assistance programs simultaneously.
• Hospital Bill Line-Item Checker — Use this tool after a hospital stay to verify your itemized bill against what Medicare should have covered, identifying potential billing errors before you pay.

Your Medicare Action Checklist — What to Do Next

These six steps are ordered by urgency. Complete them in sequence to protect your Medicare enrollment and avoid costly penalties.

1. Calculate your Initial Enrollment Period (IEP) window right now. Use the Medicare Enrollment Deadline Calculator to find your exact 7-month window based on your date of birth. Mark the start date, end date, and the 3-month-before-birthday threshold (the date you must enroll by to get Day 1 coverage) on your calendar. Do this today — regardless of how far away you are from turning 65.
2. Check your automatic enrollment status at ssa.gov. Log into your my Social Security account at ssa.gov/myaccount or call 1-800-772-1213. If you already receive Social Security retirement or disability benefits, you will be automatically enrolled in Parts A and B at 65 — no action needed unless you plan to decline Part B because of active employer coverage. If you are not receiving Social Security, you must actively apply for Medicare.
3. Verify your employer coverage status in writing. If you are still working and covered by an employer health plan at 65, ask your HR department two questions: Does your employer have 20 or more employees? Is your coverage based on your active current employment? If both answers are yes, get a signed copy of Form CMS-L564 from your employer. Keep this document — you will need it to open your Special Enrollment Period without penalty when employment ends.
4. Apply online at ssa.gov during the first 3 months of your IEP. If you need to actively enroll, go to ssa.gov/medicare and select Apply for Medicare Benefits. Apply during the first 3 months of your IEP to guarantee that coverage begins on the first day of your birthday month. Apply for Part A and Part B simultaneously unless you have confirmed qualifying employer coverage and are intentionally delaying Part B.
5. Choose your coverage path within your Medigap Open Enrollment Period. After enrolling in Part B, you have a 6-month Medigap Open Enrollment Period during which you have guaranteed issue rights — meaning no insurer can deny you a Medigap policy or charge more because of your health. This window does not repeat. Use this window to evaluate Original Medicare plus Medigap versus Medicare Advantage using the Medicare Advantage vs. Original Medicare Cost Checker.
6. Check your IRMAA exposure and Savings Program eligibility. If your 2024 MAGI exceeded $106,000 (individual) or $212,000 (married filing jointly), use the Medicare IRMAA Calculator to understand your surcharge and whether an appeal using Form SSA-44 makes sense. If your income is below those thresholds, use the Medicare Savings Programs Estimator to check whether you qualify for a program that pays your Part B premium entirely.

Save this page and return to it before any enrollment deadline, coverage change, or benefit decision. Every figure in this guide is reviewed and updated when official CMS regulations change.