The Medigap Birthday Rule: How It Works and Which States Have It

By Austin Tyler  ·  Tyler Insurance Group  ·  Updated July 2026

Most people who buy a Medicare Supplement assume the decision is permanent. You pick a plan at 65, the premium slowly climbs every year, and you figure you are stuck with it unless you are willing to answer a stack of health questions and hope an insurer says yes. In a growing number of states, that assumption is simply wrong. A quiet consumer protection called the birthday rule can let you shop your coverage for a lower price once a year, with no health review at all.

THE QUICK ANSWER In the states that have a Medigap birthday rule, if you already have a Medicare Supplement policy, you get a window each year around your birthday to switch to another insurer's plan without answering health questions. The exact terms (how many days, and whether you can change plan letters) vary by state, so the rule is worth understanding before your birthday arrives.

 

What the birthday rule actually is

A Medigap birthday rule is a state-level protection, not a federal one. In the states that have adopted it, the law creates a recurring, guaranteed-issue window tied to each policyholder's birthday. During that window, an insurer cannot use your health history to deny you or raise your rate on a comparable plan. It exists for one practical reason: to let people shop the price of coverage they already own.

That matters because Medigap plans are standardized. A Plan G sold by one company covers exactly the same benefits as a Plan G sold by another, because the federal government defines what each lettered plan includes. The only meaningful difference between two same-letter plans is the monthly premium. The birthday rule lets you move to the cheaper one without the medical underwriting that would normally stand in the way.

How it generally works

Although the details differ by state, the birthday rule tends to share the same shape wherever it exists:

• It repeats every year, timed to your birthday, rather than being a one-time event.
• You move to another insurance company offering the same (or, in some states, an equal or lesser) plan.
• No medical underwriting. The new carrier cannot ask about your health, medications, or tobacco use, and cannot decline you or charge more for a condition.
• You must already hold a Medigap policy. It is a tool for existing policyholders, not a way to buy your first supplement.
  
  

THE MOST COMMON MISUNDERSTANDING The birthday rule does not let someone on a Medicare Advantage plan move into a Medigap policy without underwriting. It applies only to people who already have a Medicare Supplement. Leaving Advantage for a supplement is a separate process with its own rules, and outside a few guaranteed-issue situations it usually still involves health questions.

The limits worth knowing

The birthday rule is generous, but it is narrow on purpose. Three limits catch people off guard:

• You usually cannot upgrade benefits. Most birthday-rule states let you move to the same plan letter you already have, and some allow an equal or lesser plan. Jumping to a richer plan generally still requires underwriting.
• The window is short. Depending on the state, it often runs somewhere in the range of a few weeks to a couple of months around your birthday. Miss it and you wait a year, or face health questions.
• It is state-specific. If your state has not adopted a birthday rule, this protection does not apply to you, though other guaranteed-issue rights still might.
  
  

Which states have a birthday rule

The list has been growing as more states adopt consumer protections for Medigap. States with a birthday rule include California, Oregon, Idaho, Illinois, Louisiana, Nevada, and Kentucky, among others, and additional states have added similar rules in recent years. The specifics vary quite a bit from state to state. Kentucky, for one, has a particularly consumer-friendly version, which our local Kentucky team breaks down in their guide to the Kentucky Medigap birthday rule. Because the terms are not uniform (the window length and whether you can change plan letters differ from state to state), the reliable move is to confirm the current rule with your own state's Department of Insurance or a licensed agent who works in your state.

Window	Guaranteed-issue, no health questions, for a set number of days each year around your birthday
What you can switch to	The same plan letter with another insurer (some states allow an equal or lesser plan)
Who qualifies	People who already hold a Medigap policy (not Medicare Advantage enrollees, not first-time buyers)
How often	Every year, as long as your state has the rule

How it differs from the federal Medigap window

It is easy to confuse the birthday rule with the one federal window that applies everywhere. They are not the same:

• Your Medigap Open Enrollment Period is federal and happens once in your life: a six-month window that begins when you are 65 and enrolled in Part B, during which any Medigap plan must accept you regardless of health.
• The birthday rule is a state protection that repeats every year, but is narrower, since it is generally limited to your existing plan letter and requires that you already have a supplement.

There are also federal guaranteed-issue and trial rights triggered by specific events, such as losing other coverage or trying Medicare Advantage for the first time. Those are separate from both windows above.

A related protection: Medigap for people under 65

While we are on the subject of state-level Medigap protections, it is worth knowing that federal law does not require insurers to sell Medigap to people who qualify for Medicare before 65 through a disability or end-stage renal disease. A number of states have stepped in to require it anyway, often with a guaranteed-issue window in the first six months of Part B and a cap that keeps under-65 premiums from exceeding what older enrollees pay for the same plan. If you or a family member is on Medicare before 65, ask whether your state offers this protection, because the rules vary widely.

How to use the birthday rule the smart way

• Treat your birthday as an annual coverage checkup. Put a reminder on the calendar to review your same-letter rate against the market.
• Gather quotes before the window opens so you are ready to act the moment it does.
• Switch cleanly. Get the new policy approved and effective before canceling the old one, so there is never a gap in coverage.
• Leave your drug plan out of it. The birthday rule is about your supplement only. Your separate Part D drug plan is reviewed in the fall during the Annual Enrollment Period.
• Confirm your state's exact terms with a licensed agent, since the window and the switch rules are not the same everywhere.

QUICK RECAP The birthday rule is a state-level protection that lets existing Medigap policyholders switch insurers around their birthday each year with no health questions. Same-letter plans are identical by law, so the rule mainly helps you shop for a lower premium on the coverage you already have. It does not let you upgrade benefits in most states, buy your first policy, or move from Medicare Advantage to Medigap without underwriting. States with a birthday rule include California, Oregon, Idaho, Illinois, Louisiana, and Nevada, among others, and the terms vary by state. It is different from the one-time federal Medigap Open Enrollment Period, which happens once at 65.

Frequently asked questions

What is the Medigap birthday rule?

It is a state law, in the states that have adopted it, that gives people who already own a Medicare Supplement a yearly window around their birthday to switch to another insurer's plan without answering health questions. It exists so you can shop for a lower premium on coverage you already have.

Who can use it?

Only people who already hold a Medigap policy, and only in states that have the rule. It is not a way to buy a first supplement, and people on Medicare Advantage cannot use it to move into Medigap without underwriting.

Can I switch to a better plan during the window?

Usually not. Most birthday-rule states limit you to the same plan letter you already have, and some allow an equal or lesser plan. Moving up to richer benefits generally still requires medical underwriting.

How long is the window?

It varies by state, commonly ranging from a few weeks to a couple of months around your birthday. Because the exact timing differs, treat your birthday as the start and act early rather than waiting until the end.

How do I find out if my state has it?

Check with your state's Department of Insurance or a licensed agent who works in your state. The list of birthday-rule states has grown in recent years, and the terms are not identical from one state to the next.

Not sure if your state has a birthday rule?

Our licensed agents can check your plan letter, compare your rate against the market, and tell you honestly whether a switch makes sense this year. No cost, no pressure.

Written by Austin Tyler, a licensed insurance agent with Tyler Insurance Group.