Most decisions about Medicare can be changed every year. One cannot, at least not easily. If you choose Medicare Advantage at 65 and later want to switch to Original Medicare with a Medigap supplement, insurers in most states can turn you down or charge more because of your health. So the question is not only which option is cheaper now, but which one you will be glad you picked at 75 or 80.
SmartCoverage Editorial Team, reviewed October 2026. How we research. Not legal or financial advice; for free one-on-one help, contact your State Health Insurance Assistance Program (SHIP).
The two paths in one paragraph each
Original Medicare is the government program: Part A for hospitals and Part B for doctors and outpatient care. You can see any doctor or hospital in the country that accepts Medicare, with no referrals and few prior approvals. But it pays only about 80% of most outpatient costs, has no yearly limit on what you owe and does not include drug coverage. Most people on it add a Medigap policy to cover the gaps and a Part D plan for prescriptions.
Medicare Advantage, or Part C, replaces all of that with a single private plan, usually an HMO or PPO, that must cover everything Original Medicare does and almost always includes drug coverage. Many plans charge no premium beyond Part B, add extras such as dental or vision, and cap your yearly costs. In return, you use the plan’s network and follow its rules, including prior authorization for many services. KFF counted 35.2 million people, 55% of those eligible, in Medicare Advantage in 2026.
Four kinds of retiree, four answers
You are healthy and your budget is tight
Advantage usually wins on cost in a good year. A plan with no extra premium leaves you paying only the Part B premium, $202.90 a month in 2026, plus copays. Medigap Plan G, the most popular option for new enrollees, adds a monthly premium that often runs from about $150 to well over $250 depending on your age, state and insurer. The question is whether you are comfortable with an out-of-pocket limit that could reach $9,250 in-network in a bad year, the 2026 federal maximum, though KFF found the average limit among enrollees was about $5,400.
You spend winters somewhere else, or travel a lot
Original Medicare with Medigap is built for this. Any provider that accepts Medicare, anywhere in the United States, is in your network. Most Advantage plans are local HMOs that cover only emergencies and urgent care outside the service area. Some PPOs pay out of network at higher cost, and a few insurers offer travel programs, so ask before you assume.
You have a serious or chronic condition
This is where the trade-off sharpens. Medigap Plan G means your costs for covered care stop at the Part B deductible, $283 in 2026, however much treatment you need, and you can see any specialist or cancer center that takes Medicare. Advantage caps your costs too, but at a higher level, and you may need referrals and prior approval for scans, procedures or drugs. Some people with chronic conditions do well in Advantage special needs plans, which coordinate care closely. Check that your specialists and hospital are in the network, and look at the plan’s star rating.
You want extras like dental and hearing
Many Advantage plans include some dental, vision and hearing coverage, which Original Medicare does not. Look at the details: dental benefits are often capped at a modest yearly amount and may cover cleanings but little major work. A standalone dental policy can be added to Original Medicare if that is what matters most to you.
Run the numbers on a real year
Pick a year below. The tool adds premiums and what you would pay for care under each option. Open the assumptions to enter real figures from plans in your area.
Price a year of care three ways
Choose a year. Each column adds premiums and what you would pay for care. The Part B premium is included in all three; drug coverage is left out because you need it with every option.
Change the plan assumptions
Care costs are illustrative Medicare-allowed amounts, not quotes. Uses the 2026 Part B premium ($202.90 a month), Part B deductible ($283) and Part A deductible ($1,736). Advantage plans vary widely; check the plan’s Evidence of Coverage. Original Medicare alone has no yearly cap. For guidance only.
Two things stand out when you try every scenario. Advantage is usually cheapest when little happens. And the cost of Medigap barely moves whatever happens, which is exactly what you are paying for.
The one-way door: Medigap and your health
You get a six-month Medigap open enrollment period that starts the month you are 65 or older and enrolled in Part B. During it, insurers must sell you any Medigap policy they offer at their standard price, whatever your health. After it ends, in most states they can ask health questions, charge more or refuse you.
That makes the first choice more important than it looks. If you start with Advantage and want to switch years later, you can always return to Original Medicare during open enrollment, but you may not be able to buy a Medigap policy to go with it. There are exceptions: a trial right lets you switch back within the first year of trying Advantage, and a few states, including New York, Connecticut, Massachusetts and Maine, give broader rights. Several others, such as California and Oregon, have annual windows. Your SHIP counselor can tell you the rules where you live.
Drugs: changes in 2027
Whichever path you choose, you need drug coverage, either a standalone Part D plan with Original Medicare or the drug coverage built into most Advantage plans. The yearly cap on what you pay for covered drugs rises from $2,100 in 2026 to $2,400 in 2027, according to Kiplinger’s summary of the 2027 changes, and the maximum Part D deductible rises to $700. A federal program that held down standalone Part D premiums in 2026 will not continue, and the number of standalone plans has been falling, so compare carefully. Newly negotiated prices for 15 drugs, including semaglutide brands such as Ozempic, take effect in 2027.
Dates that matter
Your initial enrollment period runs seven months around your 65th birthday. After that, Medicare’s annual open enrollment runs from October 15 to December 7, when you can switch between Original Medicare and Advantage or change plans for the following year. From January 1 to March 31, people already in an Advantage plan can switch plans once or return to Original Medicare. If you are still working at 65, the rules on delaying Part B are different; check before you skip it.
If you are arriving at Medicare after retiring early, our guide to health insurance for early retirees explains how income at 63 can raise your Medicare premiums at 65, and our HSA guide covers using an HSA to pay Medicare premiums tax-free. For coverage outside Medicare, see the best health insurance companies.
The cheapest answer at 65 is often Advantage. The safest answer for the long run is often Original Medicare with Medigap. Which one is right depends less on the brochure than on your health, where you spend your time and how much uncertainty you can live with.
Sources
- KFF: Medicare Advantage in 2026, enrollment update and key trends (June 2026)
- KFF: Medicare Advantage out-of-pocket limits (May 2026)
- 2026 Medicare Parts A and B premiums and deductibles
- Kiplinger: Changes coming to Medicare in 2027 (September 2026)
- Medicare.gov: Medigap (Medicare Supplement Insurance)