Medicare Supplement Plan G pays for costs that Original Medicare leaves you responsible for
Medicare Supplement Plan G (also called Medigap Plan G) is insurance you buy from a private company to cover the gaps in Original Medicare. Original Medicare — Part A and Part B — pays for a large share of your hospital and doctor bills, but leaves you with deductibles, copayments, and coinsurance. Plan G picks up most of those out-of-pocket costs.
Plan G is one of ten standardized Medigap plans. "Standardized" means that Plan G from one insurance company covers exactly the same benefits as Plan G from another company — the price differs, but the coverage does not. This makes it easier to compare plans side by side.
You buy Plan G directly from a private insurance company, not from Medicare. It works alongside Original Medicare, not instead of it. You keep your Medicare card and use it the same way; Plan G straightforward pays bills that Medicare does not.
Key Takeaways
- Plan G covers the Part A deductible, Part B deductible, Part B coinsurance, hospital coinsurance, and skilled nursing facility coinsurance that Original Medicare does not pay.
- Plan G does not cover the Part B excess charge (the amount some doctors charge above Medicare's approved rate), which is why Plan N or other plans may cost less.
- You must be enrolled in Original Medicare Part A and Part B to buy Plan G; you cannot use it with Medicare Advantage.
- You pay a monthly premium to the insurance company selling Plan G, in addition to your Medicare Part B premium.
- The best time to buy Plan G is during your Medigap Open Enrollment Period, when you cannot be denied or charged more based on health history.
What Plan G actually covers
Plan G covers these specific costs that Original Medicare leaves you to pay:
- The Part A deductible (the amount you pay before Medicare hospital coverage begins)
- The Part B deductible (the amount you pay before Medicare doctor and outpatient coverage begins)
- Part B coinsurance (usually 20% of the cost of doctor visits, outpatient surgery, and other services after you meet the deductible)
- Hospital coinsurance for days 61–90 of a hospital stay, and for 60 lifetime reserve days
- Skilled nursing facility coinsurance (usually 20% of the cost) for days 21–100 of a stay
- Blood transfusions (the first three pints per year)
- Part A hospice care coinsurance
Plan G does not cover the Part B excess charge — the amount some doctors charge above what Medicare says the service is worth. If a doctor charges $150 and Medicare approves $100, you owe the $50 difference even with Plan G. This is why some people choose Plan N instead, which costs less but leaves you responsible for the excess charge and a small copayment at doctor visits.
Plan G also does not cover dental, vision, hearing aids, or long-term care — no Medigap plan does. It does not cover prescription drugs; you need Part D for that.
How Plan G works with your Medicare bills
When you see a doctor or go to the hospital, you show both your Medicare card and your Plan G card. The provider bills Medicare first. Medicare pays its share and sends you an explanation of benefits showing what you owe. Then the provider (or you) sends that bill to your Plan G insurance company, which pays the amount Plan G covers.
In most cases, you do not handle the paperwork yourself. Providers who work with Medicare know how to bill Medigap plans directly. You may pay nothing out of pocket, or you may pay a small amount if the bill includes something Plan G does not cover.
If you see an out-of-network provider or a provider who does not accept Medicare, Plan G does not help — you would be responsible for the full bill. This is rare with Medicare providers, but it can happen with some specialists or facilities outside the United States.
Plan G costs and how to compare prices
Plan G has two costs: your monthly premium to the insurance company, and your monthly Part B premium to Medicare (which you pay whether or not you buy Plan G). The Plan G premium varies by insurance company, your age, your location, and the company's pricing method.
Insurance companies use one of three pricing methods: community-rated (everyone in your area pays the same), age-rated (younger people pay less), or issue-age-rated (your premium is based on your age when you first buy the plan and stays the same as you age). A plan that looks cheap at 65 may become expensive by 75 if it uses age-rating.
To compare Plan G prices, call insurance companies directly or use Medicare's Plan Finder tool at Medicare.gov. Get quotes from at least three companies. Ask each one whether the premium will increase with your age and by how much. The lowest price today is not always the lowest price in five years.
When you can buy Plan G and what happens if you miss the window
The best time to buy Plan G is during your Medigap Open Enrollment Period, which lasts six months starting the month you turn 65 and enroll in Medicare Part B. During this period, insurance companies cannot deny you coverage, charge you more based on your health, or exclude any condition you already have.
If you miss this window, you can still buy Plan G, but the company can refuse to sell it to you, charge you more, or exclude your existing health conditions. Some states have additional protections that extend the open enrollment period or allow you to switch plans under certain circumstances, but these vary. Once you are past the open enrollment period, your options narrow.
If you are currently on Medicare Advantage and want to switch to Original Medicare and Plan G, you have a limited window to do so. You can switch during the Medicare Annual Enrollment Period (October 15 to December 7 each year), but you will not have Medigap protections — the insurance company can deny you or charge more based on health history.
Plan G compared to other Medigap plans
Plan G is popular because it covers most of your out-of-pocket costs, but it is not the only option. Here is how it compares to two other common plans:
| Coverage | Plan G | Plan N | Plan F |
|---|---|---|---|
| Part A deductible | Covered | Covered | Covered |
| Part B deductible | Covered | Not covered | Covered |
| Part B excess charge | Not covered | Not covered | Covered |
| Doctor visit copayment | Covered | $20 copay | Covered |
| Typical monthly premium | $120–$180 | $80–$130 | $180–$250 |
Plan N costs less than Plan G but leaves you responsible for the Part B deductible (currently $240) and a small copayment at each doctor visit. Plan F covers everything Plan G does plus the Part B excess charge, but insurance companies can no longer sell Plan F to people new to Medicare after 2020 — only people who had it before that date can keep it.
Which plan makes sense depends on how often you see doctors, whether you see doctors who charge the excess, and how much the premium difference is in your area. If you rarely see doctors, Plan N might save you money. If you see many doctors, Plan G or F might be worth the higher premium.
Questions to ask your doctor or insurance company
Before you buy Plan G, ask your current doctors whether they accept Medicare and whether they ever charge the Part B excess charge. If several of your doctors charge the excess, Plan G may not be the best fit — you might want Plan F (if you can get it) or accept the excess charge with Plan G or Plan N.
Ask your Plan G insurance company whether the premium will increase with your age and by how much. Ask whether the company has a history of large rate increases. Ask what happens if you move to a different state — some companies charge different premiums in different states.
Ask Medicare or your insurance company whether you have a Medigap Open Enrollment Period coming up and how long it lasts. If you are past the window, ask what protections your state offers.
Frequently Asked Questions
Can I use Plan G with Medicare Advantage instead of Original Medicare?
No. Medigap plans, including Plan G, only work with Original Medicare (Part A and Part B). If you have Medicare Advantage, you cannot buy Plan G. If you want to switch from Medicare Advantage to Plan G, you must first switch back to Original Medicare, which you can do during the Medicare Annual Enrollment Period.
Does Plan G cover prescription drugs?
No. Medigap plans do not cover prescription drugs. You need Medicare Part D (a separate prescription drug plan) for that. You can buy Part D at the same time you buy Plan G, or at any time, though waiting past your initial enrollment period may result in a penalty.
What if I move to a different state after I buy Plan G?
Your Plan G coverage continues, but the premium may change. Contact your insurance company to find out what your new premium will be. You may also want to shop for plans in your new state, since different companies operate in different states and prices vary.
Can an insurance company refuse to sell me Plan G if I have a pre-existing condition?
Only during your Medigap Open Enrollment Period can they not refuse you or charge more based on health history. If you are outside that window, the company can deny you or exclude your existing conditions. Some states have additional protections — contact your state insurance commissioner's office to learn what applies to you.
Is Plan G the same from every insurance company?
Yes, the coverage is identical — Plan G from one company covers exactly what Plan G from another covers. The price is different, which is why shopping around matters. The customer service, claims process, and reputation may also differ, so read reviews and ask about the company's track record before you buy.