Once you sign up for Medicare Parts A and B, you face the biggest Medicare choice of all. You can stay with Original Medicare and add a Medigap supplement and a drug plan, or you can pick a Medicare Advantage plan that bundles everything together. Roughly half of people on Medicare now choose each way. Neither is right for everyone, and the trade-offs are easier to see side by side.
The two paths
Path one: Original Medicare plus Medigap. You keep Parts A and B from the government. Medicare pays about 80% of most bills, and a Medigap policy from a private insurer pays most or all of the rest. You add a separate Part D plan for prescriptions. You can see any doctor or hospital in the country that accepts Medicare, which is nearly all of them, with no referrals.
Path two: Medicare Advantage (Part C). A private insurer takes over your Medicare coverage. Plans usually include drug coverage and often add dental, vision and hearing benefits. Most use networks, such as an HMO or PPO, and many require approval before certain tests or procedures. You still pay your Part B premium.
Side by side
| Original Medicare + Medigap | Medicare Advantage | |
|---|---|---|
| Monthly premium | Higher: Part B + Medigap + Part D | Lower: Part B, often $0 extra |
| Cost when you get care | Little or nothing with most Medigap plans | Copays for visits, stays and tests |
| Yearly limit on what you pay | No limit in Original Medicare, but Medigap covers most gaps | Every plan has an out-of-pocket maximum |
| Doctors and hospitals | Any provider that takes Medicare, nationwide | Usually a network |
| Prior approval | Rarely | Common for hospital stays, scans and some drugs |
| Extras like dental and vision | Not included | Often included |
| Travel within the US | Covered anywhere | Often limited to emergencies outside the area |
What it costs in practice
Take two neighbors who both turned 65 this year, in good health.
Diane picks Original Medicare with a Medigap Plan G and a Part D plan. She pays $202.90 for Part B, about $150 for Medigap and about $40 for Part D. That is roughly $393 a month, or about $4,700 a year. When she needs care, she pays the $283 Part B deductible once, and then almost nothing else for the year, even after a hip replacement.
Frank picks a Medicare Advantage plan with no extra premium. He pays only the $202.90 Part B premium, about $2,435 a year. In a healthy year, he saves more than $2,000 compared with Diane. In a year with a hospital stay and surgery, his copays could reach the plan’s out-of-pocket maximum, which can run several thousand dollars. In that year, he could pay more than she does.
The pattern holds broadly. Medicare Advantage costs less when you are healthy. Medigap costs more every month but makes your spending predictable when you are not.
Medigap prices vary widely by state, age and insurer, so compare quotes. Our Medicare cost calculator adds up the premiums, including any income surcharge.
The deadline that matters most
Here is the part many people learn too late. Your Medigap open enrollment period lasts six months, starting the month you are both 65 or older and enrolled in Part B. During those six months, any insurer must sell you any Medigap policy it offers, at its standard price, no matter your health.
After that window closes, insurers in most states can ask health questions and turn you down or charge more. So if you pick Medicare Advantage first and want to switch to Medigap at 72 after a cancer diagnosis, you may not be able to buy a policy at all. A few states, including New York and Connecticut, let people buy Medigap at any time. A handful of others offer a yearly switching window.
There is one safety valve. If you join a Medicare Advantage plan when you first get Medicare and leave it within 12 months, you can usually buy a Medigap policy without health questions.
Who tends to choose which
Original Medicare with Medigap often fits people who:
- Have ongoing health conditions or see specialists often
- Spend part of the year in another state, or travel a lot within the US
- Want to keep doctors who may not be in an Advantage network
- Prefer paying a steady premium to facing bills when they get sick
Medicare Advantage often fits people who:
- Are healthy and want the lowest monthly cost
- Like having dental, vision and hearing in one plan
- Are comfortable with a network, especially if their doctors are in it
- Live where good Advantage plans are available
If you have retiree health coverage
Many retired teachers, state workers and company retirees get health coverage from their former employer. Some of these plans are themselves Medicare Advantage plans, and some work as a supplement to Original Medicare. Dropping a retiree plan to buy your own coverage can mean you can never get it back. Check with your pension system or benefits office before you change anything. Our guide to retiree health insurance covers how public plans work with Medicare.
Common questions
What is Medigap Plan G? It is the most popular Medigap plan for new enrollees. It covers everything Original Medicare leaves behind except the yearly Part B deductible. Plan N costs less but has small copays for doctor and emergency room visits.
Can I switch every year? You can switch Medicare Advantage plans, or move from Advantage back to Original Medicare, during open enrollment from October 15 to December 7, and Advantage members get another chance from January 1 to March 31. Getting a Medigap policy after you switch back is the hard part, because of the health questions.
Do I need Part D with Medigap? Medigap does not cover prescriptions, so yes, unless you have other creditable drug coverage. Skipping it can lead to a lifelong late penalty.
Is Medicare Advantage “free”? A $0 premium plan still requires your Part B premium, and you pay copays when you use care. It is lower cost, not no cost.