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Does Medigap cover the 20 percent Medicare does not pay?

Yes. Every Medigap plan pays the Part B coinsurance, the 20 percent Medicare leaves you. Here is what else each plan letter covers.

Updated September 3, 2026 · 3 min read · by Gerino Alejos

Yes. Every Medigap plan pays the Part B coinsurance, which is the 20 percent of the approved cost Medicare does not pay for doctor visits and outpatient care. Outpatient means care without an overnight admission. Paying that share is the core job of a supplement. See what Medigap is and how it works.

The gaps a supplement can fill

Coinsurance is the share of a bill you owe after Medicare pays its part. On a $50,000 bill, 20 percent is $10,000. Original Medicare sets no yearly limit on that 20 percent. A supplement can pick up these gaps.

• Part B coinsurance, the 20 percent. Every plan letter covers it.
• Part A hospital coinsurance, your share of an inpatient stay, plus 365 extra hospital days after Medicare's run out. Every plan letter covers it.
• The Part A hospital deductible, the amount you pay before Medicare starts paying for a stay. It applies per benefit period, not once a year. Most plans cover it.
• Skilled nursing coinsurance, your share of a stay in a nursing facility, which starts after the first stretch of days.
• The first three pints of blood.
• Hospice coinsurance, your share of comfort care at the end of life.
• Part B excess charges, the extra a doctor who does not accept Medicare's approved amount as full payment can bill above it.
• Emergency care while traveling outside the country, usually up to a lifetime limit.

Which of these your policy pays depends on the plan letter you pick.

The extra 365 hospital days

People overlook this one, and it matters. Medicare pays for a set number of hospital days in a benefit period, plus a bank of lifetime reserve days. After those, Medicare stops paying for the stay.

Every Medigap plan adds 365 more days of hospital coverage after Medicare's days are gone. On a long hospitalization, that is a very large bill you do not have to pay.

What is not covered

The Part B deductible, the amount you pay yourself each year before Part B starts paying, is no longer covered. Plans sold to people who became eligible for Medicare on or after January 1, 2020 cannot pay it.

Plans C and F did pay it, and both are closed to anyone newly eligible after that date. If you became eligible before then and already hold one, you keep it. See Plan F next to Plan G.

What this looks like in practice

With a comprehensive plan such as Plan G, you pay the Part B deductible once at the start of the year. After that, most covered care costs you nothing out of pocket.

At the office you hand over two cards, your Medicare card and your supplement card. Medicare pays its part and passes the balance along. The supplement pays that balance, and no bill reaches your mailbox.

You are trading a steady premium, the monthly bill for the coverage, for far fewer surprise medical bills.

What it still will not do

A supplement pays your share of what Medicare covers. It cannot pay for prescriptions, routine dental, vision, hearing or long term custodial care, the daily help with bathing, dressing and eating. Medicare does not cover those at all.

See the full list of what a supplement leaves out and what Medicare itself leaves out. If you want to know which plan letter fits the care you use, we can walk through it with you. Call our McAllen office at (956) 687 3334, or enter your ZIP code in the plan pricing box on this page.

Gerino Alejos

Licensed insurance agent · License 3128710 · NPN 18243381

Owner of McAllen Insurance Group, an independent agency on North 10th Street in McAllen. Works with clients across Hidalgo, Cameron and Starr counties on Medicare, Marketplace health, life and auto coverage. Se habla español.