What Is the Medigap (Medicare Supplement) Birthday Rule?

Will My Birthday Let Me Switch Medigap Plans Without Health Questions?

If you already have a Medicare Supplement (Medigap) plan, you may have heard about something called the “Birthday Rule.” In short, it gives some people a once-a-year chance to switch Medigap plans without going through medical underwriting.

Sounds great, right? The catch is — not everyone qualifies. This rule only applies if you live in California, Oregon, Illinois, Nevada, or Idaho. And even then, each state has slightly different rules.

Let’s break down how it works and whether your birthday can actually help you save money or improve your coverage.

What Is the Medigap Birthday Rule?

The Medigap Birthday Rule allows people who already have a Medigap plan to switch to another plan of equal or lesser benefits — usually around their birthday each year — without answering health questions.

This is important because, in most states, you can only switch Medigap plans later in life if you’re healthy enough to pass medical underwriting. That’s where insurers can deny you or charge more based on your health history.

With a birthday rule, you can skip that entire process — but only for a limited time and only under certain conditions.

Note: Not all states use the term “Birthday Rule.” Some have similar policies but call them by other names. Medicare rules can vary at the state level — especially for Medigap — because these plans are regulated differently than Medicare Advantage or Part D.

If you want to dive deeper into how Medicare rules differ across states, check out our guide on Medicare changes and Medicare mistakes to avoid.

For federal resources, you can review details directly at Medicare.gov or see official policy guidance at CMS.gov.

Why Doesn’t Everyone Have This Option?

Here’s where it gets confusing — Medigap is not run by the federal government. While the Centers for Medicare & Medicaid Services (CMS) set the standards for Original Medicare (Parts A & B), each state regulates Medigap plans and insurance companies.

That means your rights to switch can depend entirely on where you live.

When you first sign up for Medicare Part B, you get a one-time Medigap Open Enrollment Period — a six-month window where you can buy any Medigap plan without health questions. After that, you’re usually locked in unless you move, lose coverage, or qualify under state-specific rules like this one.

If you’re nearing your 65th birthday, read our guide on turning 65 and Medicare enrollment — it explains how to time your decisions and avoid missing your guaranteed-issue window.

States That Offer a Medigap Birthday Rule

Here’s a quick breakdown of how the Birthday Rule works in each state that offers it:

California

• When: 30 days before and 60 days after your birthday
• What you can do: Switch to a plan of equal or lesser benefits
• Medical underwriting: Not required
• Tip: You can switch carriers, but you can’t “upgrade” (for example, from Plan N to Plan G)

Oregon

• When: 30 days before and 30 days after your birthday
• What you can do: Switch to a plan of equal or lesser benefits
• Medical underwriting: Not required
• Tip: Like California, you can switch companies but not move up to a higher-benefit plan

Illinois

• Who qualifies: Ages 65–75 only
• When: Up to 45 days after your birthday
• What you can do: Switch plans within your current company only
• Medical underwriting: Not required
• Tip: You can downgrade coverage but can’t move carriers

Nevada

• When: Starting the first day of your birthday month, for 60 days
• What you can do: Switch to a plan of equal or lesser benefits with any carrier
• Medical underwriting: Not required

Idaho

• When: Beginning on your birthday, for 63 days
• What you can do: Switch to a plan of equal or lesser benefits with any carrier
• Medical underwriting: Not required

Pro tip: Your birthday might be more than just cake and candles — it could be your best chance all year to get a better Medigap plan without worrying about your health history.

What About Other States?

Even if your state doesn’t have a “Birthday Rule,” some offer other guaranteed-issue rights — for example, letting you switch Medigap plans when your insurer exits the market or when you move.

If your Medicare Advantage plan is ending, read our article on Medicare Advantage ending or Medicare service area reductions to understand your options.

Final Thoughts

If you live in a state with a Medigap Birthday Rule, your birthday might be more than just a celebration — it could be your best chance to switch Medigap plans without health questions. But remember, every state’s rule is different. Don’t assume what works for California applies to Illinois or Idaho.

Before making a change:

• Double-check your state’s eligibility window
• Compare plan options early
• Confirm your new policy approval before dropping your current coverage

Staying informed and planning ahead can help you avoid costly mistakes — and make sure you’re always in a plan that fits your needs and your budget.

If you want to stay proactive with your coverage, learn how to spot issues early using your Medicare ANOC.