Plan G is a standardized Medicare supplement that covers most of the costs Medicare Part A and Part B don't pay

Plan G fills the gaps in Original Medicare by paying your share of doctor visits, hospital stays, and other covered services. When you see a doctor or go to the hospital, Medicare pays its portion first, then Plan G pays most or all of what you owe — depending on what the service is and which gap you're looking at.

Plan G is one of ten standardized supplement plans (labeled A through N). The word "standardized" means that every insurance company selling Plan G must cover exactly the same benefits. The price varies by company and by where you live, but the coverage is identical no matter which insurer you choose.

This is different from Medicare Advantage (Part C), which replaces Original Medicare entirely. With Plan G, you keep your Original Medicare coverage and add the supplement on top of it.

Key Takeaways

  • Plan G pays Medicare's coinsurance and copayments for Part A and Part B services, but you still pay the Part B deductible yourself.
  • Every Plan G policy covers the same benefits regardless of which insurance company sells it, though premiums vary by company and location.
  • You must have Original Medicare (Part A and Part B) to buy Plan G; it does not work with Medicare Advantage.
  • Plan G does not cover prescription drugs, dental, vision, or hearing — you need a separate Part D plan for prescriptions.
  • The best time to buy Plan G is during your Initial Enrollment Period, when insurers cannot deny you or charge more based on health history.

What Plan G actually covers

Plan G covers the coinsurance (your percentage of the cost) and copayments (fixed dollar amounts per visit) that Medicare Part A and Part B require you to pay. For example, if Medicare covers a doctor visit but you owe a $25 copay, Plan G pays that $25. If you spend three days in the hospital and Medicare requires you to pay 20 percent of the cost, Plan G pays that 20 percent.

Plan G also covers the full cost of a second opinion before surgery and covers emergency care outside the United States (up to the plan limits). It pays for blood transfusions and the first three pints of blood you need in a hospital or skilled nursing facility.

One important gap: Plan G does not pay the Part B deductible, which is the amount you must pay out of your own pocket before Medicare starts paying for Part B services. You pay this deductible yourself each year. Plan G covers everything after that deductible is met.

What Plan G does not cover

Plan G is designed to work with Original Medicare, so it covers only what Original Medicare covers. It does not cover prescription drugs, dental work, vision care, hearing aids, or long-term care. These services fall outside Medicare's scope entirely.

If you need prescription drug coverage, you must sign up for a separate Part D plan through Medicare. Dental, vision, and hearing are available through standalone plans or through some Medicare Advantage plans, but not through Plan G.

Plan G also does not cover services that Medicare itself does not cover — such as cosmetic surgery, routine foot care (unless you have diabetes), or most acupuncture. If Medicare says no, Plan G says no.

How Plan G premiums and costs work

You pay three separate costs when you have Plan G: your Medicare Part B premium (paid to Medicare), your Plan G premium (paid to the insurance company), and any out-of-pocket costs for services Plan G does not cover.

Plan G premiums vary widely by insurance company and by state. In some states, a Plan G premium might be $100 per month; in others, it might be $200 or more. The same plan from different companies can cost very differently, so comparing quotes is worth your time. AARP, United Healthcare, Humana, and Cigna are among the larger sellers, but dozens of regional insurers also offer Plan G.

Insurance companies use different pricing methods. Some charge the same premium to everyone the same age, regardless of health history. Others charge based on your age when you enroll (and that rate stays with you). Still others increase premiums as you age. Ask each company how they price their Plan G before you enroll.

When you can buy Plan G and what happens if you miss the window

The best time to buy Plan G is during your Initial Enrollment Period, which runs for six months starting the month you turn 65 and enroll in Medicare Part B. During this window, insurance companies cannot deny you coverage or charge you more because of health problems you have.

If you miss this window, you enter what Medicare calls Open Enrollment. During Open Enrollment (January 1 through March 31 each year), you can still buy Plan G, but insurance companies may ask health questions and can legally deny you or charge you a higher premium based on your health history. Some states have protections that limit this, but not all.

If you are already on a different Medicare supplement plan and want to switch to Plan G, you can do so during Open Enrollment without health questions, as long as you are switching from another supplement plan. Switching from Medicare Advantage to Plan G is more complicated and may involve health underwriting.

Plan G versus other Medicare supplement plans

Plan G is one of the most popular supplements because it covers nearly all the gaps in Original Medicare. The main difference between Plan G and Plan N is that Plan N requires you to pay a copay for some doctor visits and emergency room visits, while Plan G does not. Plan N premiums are usually lower, so the choice depends on whether you want lower monthly costs or lower costs when you use care.

Plan F is older and more generous than Plan G — it covers the Part B deductible, which Plan G does not. However, Plan F is no longer sold to people new to Medicare. If you enrolled in Medicare before January 1, 2020, you may still be able to buy Plan F, but new enrollees cannot.

Plans A, B, C, and D cover fewer gaps and have lower premiums but higher out-of-pocket costs when you use services. Plans H, I, J, K, and L are rarely sold today. Plan N is the main alternative to Plan G for people who want to balance premium cost against coverage.

How to compare Plan G quotes and choose an insurer

Start by contacting three to five insurance companies that sell Plan G in your state. You can find a list on Medicare.gov or by calling Medicare at 1-800-MEDICARE. Ask each company for a quote based on your age and state of residence. Write down the monthly premium, any waiting periods for pre-existing conditions, and how the company adjusts premiums as you age.

Check the company's customer service ratings through the National Association of Insurance Commissioners (NAIC) or through your state's insurance commissioner's office. Read recent customer reviews on independent sites, but remember that people are more likely to leave reviews when they are angry than when they are satisfied.

Once you choose a company, you can enroll through their website, by phone, or by mail. Enrollment takes about two weeks to process. Your coverage typically starts on the first day of the month after the insurance company receives your process.

Frequently Asked Questions

Can I use Plan G with any doctor or hospital?

Yes. Because Plan G works with Original Medicare, you can see any doctor or hospital that accepts Medicare. You are not limited to a network. This is one of the main advantages of Plan G over Medicare Advantage, which often requires you to use doctors in a specific network.

What happens to my Plan G if I move to a different state?

Your Plan G coverage continues, but your premium may change because rates vary by state. Contact your insurance company to find out your new rate. You can also shop for a new Plan G from a different company in your new state during Open Enrollment (January 1 through March 31) without health questions.

Do I still need Part D prescription drug coverage if I have Plan G?

Yes. Plan G does not cover prescriptions at all. You must sign up for a Part D plan separately through Medicare. If you do not enroll in Part D when you first become may be able to access, you may pay a penalty for late enrollment when you do sign up.

What is the Part B deductible, and why doesn't Plan G cover it?

The Part B deductible is the amount you must pay out of pocket before Medicare starts paying for Part B services like doctor visits and outpatient care. It changes each year — in recent years it has been around $200 to $240. Plan G covers costs after this deductible is met, but you pay the deductible itself. Plan F (available only to those who enrolled in Medicare before 2020) does cover it.

Can I switch from Plan G to a different supplement plan later?

Yes, during Open Enrollment (January 1 through March 31) each year, you can switch to any other supplement plan without health questions. Outside of Open Enrollment, switching may require health underwriting and the new company can deny you or charge more based on your health history.