Tool · Free · Browser-only

Federal Medigap OEP decoder

Enter your date of birth, the date your Medicare Part B is (or will be) effective, and your state. We’ll compute the exact dates of your federal 6-month Medigap Open Enrollment Period and surface any state-specific protections.

Privacy: The calculation runs entirely in your browser. Your DOB, Part B date, state, and Medicaid status never leave your device. No account. No email. No retargeting.

When does my federal 6-month Medigap window close?

Enter your date of birth, the date your Medicare Part B is (or will be) effective, and your state. We’ll show you the exact dates of your federal 6-month Medigap Open Enrollment Period, plus any state-specific protections that apply. Your inputs stay in your browser— the calculation runs entirely on your device.

Date of birth

Used only on your device. Not transmitted.

Medicare Part B effective date

From your Medicare card or your “Welcome to Medicare” letter. If your Part B starts later (e.g., still on employer coverage), use that future date.

State of residence

Currently enrolled in Medicaid?

YesNo

If “yes,” we’ll explain why Medigap is generally not the right product for active-Medicaid beneficiaries.

No account, no email, no signup.

How the decoder calculates your window

The federal Medigap Open Enrollment Period is anchored to the first calendar month in which you are both 65 or older AND enrolled in Medicare Part B. The window runs six full calendar months from that anchor month (anchor month + the next five). During the window, federal law (per 42 U.S.C. § 1395ss) requires every insurer that sells Medigap in your state to issue you a policy regardless of your health status.

If you delay your Part B enrollment (because you’re still working with employer coverage, on TRICARE, or have other qualifying coverage), your federal Medigap OEP doesn’t expire at age 65 — it begins later, anchored to the first month you actually have Part B at age 65+. Read the federal OEP rule in detail.

If your federal OEP has already closed, federal qualifying-event guaranteed-issue protections may re-open a Medigap window. See federal 30-day-look-back qualifying events. Your state may also have continuous or annual GI rules beyond the federal floor — see your state page.

Federal Medigap statute (42 U.S.C. § 1395ss / Section 1882 SSA)

Last verified:2026-05-11Source:medicare.gov — When can I buy a Medigap policy?