What Is Original Medicare?
Health insurance in retirement can be one of the most confusing parts of turning 65. There’s a good chance you’ve heard the term “Medicare” tossed around – maybe from a TV commercial, a letter in the mail, or a well-meaning friend or family member offering advice.
But figuring out exactly what it covers, how to sign up, what it costs, and whether you need anything else can feel overwhelming.
The good news? You’re not alone – and this guide is here to help.
This post focuses on Original Medicare, the core of the Medicare program that millions of Americans rely on for their health coverage. Whether you’re approaching eligibility, helping a parent or spouse through the process, or simply want to better understand your options, we’ll break everything down into manageable pieces.
You’ll learn:
- What Original Medicare includes
- How much it costs
- What it doesn’t cover
- How you can fill the coverage gap
We’ll also walk through enrollment timelines, eligibility rules, and some common questions that trip people up along the way.
Our goal is to make Medicare clear, so you can make confident decisions about your healthcare without needing a dictionary or a degree in insurance.
Let’s start with the basics: what exactly is Original Medicare, and how does it work?
Medicare Basics: Original Medicare Explained
Original Medicare is the traditional health insurance program provided by the U.S. government. It’s been around since 1965 and was created to help older Americans afford necessary medical care.
Today, it serves over 66 million people, including seniors and certain younger individuals with disabilities or serious health conditions.
It includes two main parts: Part A (hospital insurance) and Part B (medical insurance). These work together to cover a wide range of healthcare services, though not everything is included.
Original Medicare’s flexibility is especially appealing. You can see any doctor or use any hospital nationwide that accepts Medicare, and there are no provider networks or required referrals.
Let’s break down Part A and Part B.
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Medicare Part A - Hospital Insurance
Medicare Part A helps cover care when you’re admitted to a medical facility, such as a hospital or skilled nursing center.
It also includes some hospice care and limited home health services.
What’s covered under Part A:
- Inpatient hospital stays, including semi-private rooms, meals, nursing care, and medications
- Skilled nursing facility care (after a hospital stay of at least 3 days)
- Hospice care for terminally ill patients
- Limited home health services, like physical therapy or wound care
Most people pay $0 premium if they or their spouse paid Medicare taxes for at least 10 years (40 quarters).
If you haven’t met that work requirement, premiums can range up to $518 per month (2025 figure).
Deductible and coinsurance:
- In 2025, there’s a $1,676 deductible for each hospital stay (per benefit period).
- After the deductible, you pay: $0 for days 1–60 in the hospital | $419 per day for days 61–90 | $838 per day after day 90 (unless you use “lifetime reserve days”)
Eligibility – You’re eligible for Part A at age 65 if you’re a U.S. citizen or permanent legal resident and either:
- You or your spouse worked and paid Medicare taxes for at least 10 years, or
- You qualify through a disability (after 24 months of Social Security Disability Insurance), or
- You have end-stage renal disease or ALS
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Medicare Part B - Medical Insurance
Part B focuses on care you receive outside the hospital – basically, the everyday services and treatments that help you stay healthy and manage chronic conditions.
What Part B covers:
- Doctor visits (primary care and specialists)
- Outpatient care (including surgeries, ER visits, and urgent care)
- Preventive services (like screenings, flu shots, and annual wellness exams)
- Durable medical equipment (DME) such as walkers, oxygen tanks, and wheelchairs
- Mental health services, lab work, and diagnostic tests
The standard monthly premium in 2025 is $185, though it may be higher depending on your income (via Income-Related Monthly Adjustment Amounts, or IRMAA).
If your modified adjusted gross income (MAGI) is above certain thresholds, you may pay an additional surcharge.
Deductible and coinsurance:
- In 2025, the annual deductible is $257.
- After that, Medicare typically pays 80% of approved services, and you pay the remaining 20%, with no cap on out-of-pocket costs unless you have supplemental coverage.
Eligibility – You qualify for Part B if:
- You’re 65 or older and eligible for Part A (you can enroll in both at the same time)
- You’re under 65 and eligible for Medicare through disability
- You pay a monthly premium to enroll, even if Part A is free
What Original Medicare Doesn’t Cover
While Original Medicare (Parts A and B) offers broad protection, it’s far from comprehensive. Many people are surprised to learn how much they’ll still need to pay out of pocket, and which services aren’t covered at all.
Let’s break it down into two categories: non-covered services and cost-sharing requirements.
Services Not Covered by Original Medicare
Here’s a look at some of the most commonly needed services that Original Medicare does not cover:
- Prescription drugs you take at home (you’ll need a separate Part D plan for this)
- Routine dental care, including exams, cleanings, fillings, dentures, and extractions
- Eye exams and eyeglasses for vision correction
- Hearing aids and related exams
- Long-term care or custodial care, such as assistance with bathing, dressing, or eating in a nursing home or assisted living facility
- Overseas medical care, except in very limited emergency situations
- Acupuncture, with limited exceptions (such as for chronic low back pain)
- Cosmetic surgery, except when medically necessary
These exclusions can become especially problematic for older adults. For example, about 70% of people over age 65 will need some form of long-term care at some point, yet Medicare will not pay for most of it.
What You Still Pay With Original Medicare
Even for the services Medicare does cover, you are still responsible for a share of the cost. These expenses are often called “cost-sharing” and can include deductibles, copayments, and coinsurance.
Here’s a breakdown of what you’ll typically owe:
Part A (Hospital Insurance)
- Deductible: $1,676 per benefit period in 2025
- Coinsurance: $0 for days 1–60 of inpatient hospitalization | $419 per day for days 61–90 | $838 per day for days 91–150 (lifetime reserve days) | All costs after 150 days
Part B (Medical Insurance)
- Deductible: $257 per year in 2025
- Coinsurance: 20% of the Medicare-approved amount for most outpatient services after meeting your deductible
- No out-of-pocket maximum: Original Medicare does not cap how much you could pay in a given year
According to the Kaiser Family Foundation, Medicare beneficiaries spend an average of $7,000 per year on total healthcare costs, even with Original Medicare.
And about 1 in 5 spend more than 20% of their annual income on medical expenses.
Why These Gaps Matter
Without supplemental insurance (like a Medigap plan or a Medicare Advantage plan), beneficiaries are on the hook for all these costs. This can lead to significant financial strain, especially for those living on a fixed income.
The unpredictability of out-of-pocket costs is one of the main reasons nearly 14 million people have chosen to purchase Medigap plans, which help cover the deductibles and coinsurance that Medicare leaves behind.
If you’re planning your retirement health strategy, understanding these gaps is essential. Whether you choose to cover them with additional plans or budget for them out of pocket, the key is knowing what to expect before the bills arrive.
Later on, we’ll discuss some options to help fill the coverage gaps left by Original Medicare.
Enrolling in Original Medicare
Enrolling in Medicare is a big milestone – one that marks an important step toward protecting your health in retirement. But as with many government programs, the rules and timelines can feel a bit tangled.
Should you sign up right away? Will it happen automatically? What if you’re still working?
Let’s walk through the process together so you know exactly what to expect, whether you’re nearing 65, working past retirement, or helping a loved one through the journey.
When Enrollment Happens Automatically
For many people, Medicare enrollment is surprisingly easy. If you’ve already started collecting Social Security or Railroad Retirement Board benefits at least four months before your 65th birthday, then you’ll be enrolled in Medicare automatically.
You won’t need to fill out a single form.
A few months before your birthday, you’ll get a red, white, and blue Medicare card in the mail. It will list your coverage start date and show that you’re enrolled in both Part A (hospital insurance) and Part B (medical insurance).
Your coverage begins on the first day of your birthday month – unless your birthday is on the first, in which case it starts the month before. That’s it. You’re covered.
When You Need to Sign Up Yourself
Not everyone is automatically enrolled, though. If you haven’t started collecting Social Security benefits by the time you turn 65 – for example, if you’ve decided to delay retirement – you’ll need to take action. Medicare won’t enroll you unless you ask.
Luckily, signing up is pretty straightforward. You can do it online at ssa.gov, by calling Social Security directly, or by visiting your local Social Security office in person (just be sure to make an appointment ahead of time).
This situation is more common than you might think, especially among people still working and receiving health insurance through an employer. If that’s you, keep reading, because your timing matters.
Your First Enrollment Window: The IEP
Medicare gives you a seven-month window around your 65th birthday to enroll. It’s called the Initial Enrollment Period (IEP), and it begins three months before your birthday, includes your birthday month, and ends three months after.
For example, if your birthday is in July, your IEP runs from April 1 to October 31. Enroll early in that window, and your coverage will begin right as you turn 65. Enroll later, and your coverage could be delayed.
It’s best to mark your calendar and aim for those early months if possible. That way, your Medicare coverage kicks in with no interruptions or last-minute surprises.
Here’s a quick look at when your Medicare coverage begins, depending on when you enroll during your IEP:
| When You Enroll | Coverage Start Date |
|---|---|
| 3 months before turning 65 | 1st day of birthday month |
| During birthday month | 1st day of following month |
| 1 month after birthday | 2nd month after enrollment |
| 2–3 months after birthday | 3rd month after enrollment |
What If You Miss the Window?
If your IEP comes and goes without enrolling, and you don’t have other qualifying coverage, you could face permanent late enrollment penalties. That’s right: your monthly premium for Part B could be higher for the rest of your life.
For Part B, the penalty adds 10% to your monthly premium for each 12-month period you delayed enrollment. It might not sound like much, but it adds up over time, especially if you’re on a fixed income.
You’ll also have to wait for the General Enrollment Period, which only happens once a year, from January 1 to March 31. If you sign up then, your coverage won’t begin until July. That’s a long time to go without protection.
Special Rules for Those Still Working
Still working at 65 and covered through your employer? You may be able to delay Medicare enrollment without a penalty, as long as your employer coverage qualifies as creditable coverage under Medicare rules.
Once you stop working or lose that coverage, you’ll get a Special Enrollment Period. It lasts eight months and lets you sign up for Medicare without a penalty.
But here’s the catch: COBRA and retiree health coverage don’t count. If you rely on those alone, you may be penalized for delaying Medicare enrollment.
So, if you’re planning to retire soon, talk with your employer’s HR team or benefits administrator. Clarify whether your coverage lets you safely delay Medicare, and make sure your paperwork lines up with Medicare’s timing.
Enrolling Under Age 65 (Disability or Serious Illness)
You don’t have to be 65 to qualify for Medicare. If you’ve been receiving Social Security Disability Insurance (SSDI) for 24 months, you’ll automatically be enrolled in Medicare – no action needed.
And if you’ve been diagnosed with ALS (Lou Gehrig’s disease) or end-stage renal disease (ESRD), your enrollment may happen even sooner, often without the 24-month wait.
The rules for these situations can be more complex, but the bottom line is: Medicare isn’t just for retirees. It’s also a critical lifeline for millions of people managing serious or chronic health conditions.
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Enrollment Tips:
- Mark your calendar a few months before turning 65 to research and prepare
- Sign up early in your IEP to avoid delays and lock in your start date
- If you’re still working at 65, talk to your employer’s HR department to confirm whether your current insurance allows you to delay Medicare without penalty
- If in doubt, contact Medicare or Social Security for personalized guidance
Options for Filling the Original Medicare Gaps
If you decide to stay with Original Medicare, you’ll want to consider how to manage the out-of-pocket costs for the services it doesn’t cover.
Here are the main options:
#1. Medigap (Medicare Supplement insurance) – Helps pay for deductibles, copays, and coinsurance left over from Original Medicare. In fact, about 14 million people are enrolled in Medigap plans as of 2024, highlighting how popular they are for managing costs and avoiding surprises.
#2. Medicare Advantage – An all-in-one plan that replaces Original Medicare and may include extra benefits, but with restrictions.
#3. Part D drug plan – Adds prescription drug coverage through a private insurer.
#4. Out-of-pocket – Some people choose to go without supplemental coverage and pay costs as they arise. This works best for those with few medical needs and high financial flexibility.
A Word of Caution About Medicare Advantage Plans
While Medicare Advantage (also known as Part C) is a popular alternative to Original Medicare, it’s not always the best fit for everyone.
These plans are offered by private insurance companies and often include additional benefits like dental, vision, and prescription drug coverage. They can sound like a great deal, but there are some important limitations to consider.
Most Medicare Advantage plans:
- Use provider networks, meaning you may be restricted to certain doctors or hospitals in your area.
- Often require prior authorization for procedures or specialist visits, which can lead to delays or denials of care.
- May change their benefits or networks each year, which can make it harder to plan long-term.
In fact, a 2023 report from the Office of Inspector General found that Medicare Advantage plans denied approximately 13% of prior authorization requests that would have been approved under Original Medicare.
That’s a significant number, especially for people managing chronic or serious illnesses.
These plans can work well for some people, particularly those who prefer a lower monthly premium and are comfortable with provider networks.
But for others – especially frequent travelers, snowbirds, or those with complex health needs – Original Medicare combined with a Medigap policy offers more flexibility and fewer administrative hurdles.
Why Many People Choose Medigap Over Medicare Advantage
If you’ve decided (hopefully) against Medicare Advantage, you’ll need to decide how to help with those costs that Medicare doesn’t pay, like deductibles, copays, and coinsurance.
While Medicare Advantage plans offer some extra benefits, many people find that Medigap provides more predictable costs, better flexibility, and fewer barriers to care.
Medigap by the Numbers
- According to the National Association of Insurance Commissioners (NAIC), as of 2024, fourteen million beneficiaries were enrolled in Medigap plans.
- Among Medigap enrollees, about 58% choose Plan F or Plan G, which offer the most comprehensive benefits.
- Nearly 90% of Medigap users report being satisfied with their plan, particularly noting peace of mind and reduced billing surprises.
- While Medigap premiums are higher than Medicare Advantage premiums (averaging $150–$250/month, depending on age, location, and plan), they help protect against high, unexpected costs later in the year.
Let’s take a closer look at why so many beneficiaries prefer Medigap – and whether it might be the right fit for you.
What Is Medigap?
Medigap is supplemental insurance that works alongside Original Medicare (Parts A and B). It helps pay for your out-of-pocket costs, like:
- Part A deductibles and coinsurance
- Part B coinsurance (the 20% you normally pay)
- Emergency care when traveling outside the U.S.
- Skilled nursing facility coinsurance (for some plans)
In most states, there are 10 standardized Medigap plans available (Plans A, B, C, D, F, G, K, L, M, and N), each offering a different level of coverage. Plan G and Plan N are among the most comprehensive and popular for new enrollees.
Private insurance companies offer Medigap policies, but the benefits of each plan letter are the same regardless of insurer; only the extra perks and premium prices differ.
Key Reasons to Consider Medigap
#1. Nationwide Provider Access: Unlike Medicare Advantage, which typically limits you to a provider network, Medigap lets you see any doctor or specialist in the U.S. who accepts Medicare – no referrals needed.
#2. Predictable Out-of-Pocket Costs: With Medigap, many of your copays and coinsurance amounts are either reduced or eliminated entirely. Some plans, like Plan G, cover everything except the Part B deductible, making costs easy to budget for.
#3. No Prior Authorization Hassles: Medigap plans follow Original Medicare’s rules, so you won’t need approval for most services. In contrast, many Medicare Advantage plans require prior authorization for services like MRIs, surgeries, or home health, potentially causing delays or denials.
#4. Travel Flexibility: Many Medigap plans cover emergency care abroad, while most Medicare Advantage plans only cover you within your regional network. For retirees who travel often or live in multiple states, Medigap provides unmatched freedom.
While Medicare Advantage may seem attractive for its low premiums and bundled benefits, many people find that Medigap offers a smoother, more reliable experience. With fewer restrictions and broad access to care, Medigap puts control back in your hands, especially if you value freedom, predictability, and comprehensive coverage.
Here’s a side-by-side comparison chart clearly outlining the key differences between Medigap and Medicare Advantage.
| Feature | Medigap (Supplement) | Medicare Advantage (Part C) |
|---|---|---|
| Works With | Original Medicare (Parts A & B) | Replaces Original Medicare |
| Provider Access | Any provider in the U.S. who accepts Medicare | Must use plan's network (often regional) |
| Referrals Required? | No | Often yes (especially for specialists) |
| Prior Authorization? | Rarely required | Frequently required for tests/procedures |
| Prescription Drug Coverage | Not included (buy Part D separately) | Usually included in the plan |
| Monthly Premiums | Typically $150–$250 | Often $0–$100 (plus Part B premium) |
| Out-of-Pocket Costs | Minimal if using Plan G or F | Can be substantial depending on plan use |
| Annual Out-of-Pocket Limit | No limit (but costs are low with Medigap) | Yes – usually $4,000–$8,000+ |
| Coverage Stability | Benefits are standardized, rarely change | Plan benefits and costs can change yearly |
| Travel Flexibility | Nationwide access + some foreign emergency | Limited to service area (usually U.S. only) |
| Best For | Frequent healthcare users, travelers, those who want cost predictability | Budget-conscious users comfortable with networks |
Bottom Line: Medigap is likely your best bet if you can afford the higher monthly premium and want the peace of mind of knowing your costs and coverage won’t change year to year.
Bottom Line
Original Medicare is the foundation of health coverage for over 66 million Americans. It’s simple, flexible, and widely accepted, offering nationwide access to doctors and hospitals without the limitations of networks or referrals.
At its core, it includes Part A (hospital insurance) and Part B (medical insurance), working together to cover everything from hospital stays to doctor visits, preventive services, lab tests, and outpatient care.
But while Original Medicare covers a lot, it doesn’t cover everything. Prescription drugs, dental, vision, hearing, and long-term care are all excluded. You’re also responsible for deductibles, coinsurance, and other out-of-pocket costs, with no cap on how much you might spend in a given year.
That’s where Medigap comes in.
Medigap pairs seamlessly with Original Medicare, helping you cover costs like the Part A deductible, the 20% coinsurance under Part B, and even emergency care when traveling abroad.
Unlike Medicare Advantage plans, Medigap gives you full freedom to see any provider in the U.S. who accepts Medicare, without worrying about networks, referrals, or prior authorizations. For many people, this peace of mind is worth the slightly higher monthly premium.
In fact, nearly 14 million Americans have chosen Medigap for these reasons, and surveys show that nearly 9 in 10 are satisfied with their decision, especially when it comes to avoiding surprise bills and navigating care easily.
So, if you’re looking for nationwide flexibility, predictable costs, and confidence in your coverage, Original Medicare with a Medigap plan may be your best option.
And if you’re unsure where to begin, we’re happy to help walk you through your Medigap options, step by step.
Sources: What Is Original Medicare? | Medicare Part A | Medicare Part B | What Is Not Covered by Original Medicare?
FAQs
- Can I have employer coverage and Original Medicare at the same time?
- Does Original Medicare cover telehealth visits?
- Can I use Original Medicare in U.S. territories like Puerto Rico or Guam?
- Is there a way to track what Medicare has paid for?
- Does Original Medicare cover chiropractic care?
- What happens if my doctor stops accepting Medicare?
