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Key takeaways
- Original Medicare has many parts. Medicare Advantage is all-in-one.
- Any doctor who accepts Medicare can be used in original Medicare.
- Medicare Advantage coverage varies by plan for in-network, out-of-network providers.
- Both must cover the same services, but costs differ between the two.
- Original Medicare goes anywhere in U.S. Medicare Advantage has geographic limits.
- Many states’ Medigap rules make it hard to leave Medicare Advantage.
Once you’re signed up for Medicare Parts A and B, you get to choose the type of coverage that best meets your needs — original Medicare or a Medicare Advantage plan.
If you decide on federally run original Medicare, you’ll have several separate pieces that work together:
- Part A helps pay for inpatient hospital and skilled nursing care, some home care and end-of-life hospice care.
- Part B covers doctors’ services, diagnostic screenings, durable medical equipment, lab tests, outpatient care and preventive services.
- A separate Part D plan is available to purchase because original Medicare doesn’t cover prescription drugs that you pick up from pharmacies.
- A Medicare supplement policy, better known as Medigap, also can be bought to help with Medicare’s deductibles and copayments.
If you choose a Medicare Advantage (MA) plan issued by commercial insurers, you may have Part A, Part B and Part D all in one plan. Nearly 90 percent of MA plans for individual enrollment include prescription drug coverage in 2026, according to KFF, a nonprofit, nonpartisan health care research organization.
As of June 2026, MA plans enrolled 51 percent — 36.1 million — of Medicare's 70.6 million beneficiaries.
If you select an MA plan, you’re not allowed to purchase a Medigap policy. MA plans have different copayments and deductibles, compared with original Medicare.
On average, Medicare beneficiaries can choose from 28 MA plans with prescription drug coverage in 2027, down from 32 options in 2026, KFF says.
Among all MA plans, including those with and without prescription drug coverage, the average beneficiary can choose from 35 plans in 2027, down from 39 in 2026, KFF says.
“There are trade-offs in choosing one kind of coverage over the other,” says Meredith Freed, a senior policy manager with KFF’s Program on Medicare Policy.
“A Medicare Advantage plan may have zero-dollar premiums, availability of extra benefits, reduced cost sharing for many services and an out-of-pocket spending limit,” Freed says. “Those things are attractive to people, but it also comes with provider networks and prior authorization.”
You’ll use Medicare differently depending on whether you pick original coverage or MA. Here’s a comparison of how each works.
The way you pay for your doctors could change
Original Medicare. You can choose any primary care doctor or specialist who accepts Medicare. You don’t need referrals to see any provider, and you don’t have to worry about your doctor leaving a plan’s network.
Only 2 percent of doctors who treat adults don’t participate in Medicare, according to KFF. So chances are good that your current doctor accepts Medicare and you won’t have to change providers.
But be aware: If you’re looking for a new doctor, about 1 in 7 primary care physicians won’t take new patients in general. That’s something to note if you plan to move or your doctor is retiring.
Medicare Advantage. Similar to employer coverage, with provider networks that limit you to their doctors, these plans may not pay for out-of-network services. So your costs will increase if you use a doctor not in the network.
Often, you’ll have a primary care physician coordinating your care, but many MA enrollees need a referral to see a specialist. Make sure the doctors you want to see are in the plan’s network.
Next in Series
Understanding Medicare Part A Hospital Costs
Learn about benefit periods, deductibles and copayments