What is the federal Medigap Open Enrollment Period?

The federal Medigap Open Enrollment Period is a one-time, 6-month window during which federal law (42 U.S.C. § 1395ss) requires every Medigap insurer to issue you a policy regardless of your health status. It automatically begins the first calendar month in which you are both 65 or older and enrolled in Medicare Part B.

How do I find the exact dates of my Medigap window?

Enter your date of birth and Medicare Part B effective date into the MedigapWindow.com OEP decoder. The calculation runs entirely in your browser — your inputs never leave your device. The decoder returns the exact start date, exact end date, and days remaining for your federal 6-month Medigap Open Enrollment Period.

Are there 10 different Medigap plans?

Yes. The federal Medigap system has 10 standardized plan letters: A, B, C, D, F, G, K, L, M, and N. Plans C and F are closed to people newly Medicare-eligible on or after 2020-01-01 per MACRA 2015. Massachusetts, Minnesota, and Wisconsin do not use the federal letter system — those states operate distinct Medigap plan structures.

Do all states have the same Medigap rules?

The federal 6-month Medigap Open Enrollment Period applies in every state. Beyond that federal floor: Connecticut, Maine, Massachusetts, and New York have continuous or annual guaranteed-issue rules; California and Oregon have annual birthday-rule switching windows; Massachusetts, Minnesota, and Wisconsin operate distinct plan structures that don't use the federal 10-letter system.

Is MedigapWindow.com a broker?

No. MedigapWindow.com is an informational website — it is not a Medicare broker, not a government agency, and not affiliated with the federal Medicare program. The site does not currently route users to compensated broker referrals. For free benefits counseling, the site surfaces each state's SHIP (State Health Insurance Assistance Program) counselor.

Federal 6-month window · Statute-cited

Find your federal 6‑month Medigap window — and the rules in your state.

Enter your date of birth and Medicare Part B effective date. We’ll compute the exact dates of your federal Medigap Open Enrollment Period plus your state-specific protections. Statute-cited. Free. Your inputs stay in your browser.

Calculate my OEP window Compare 10 plan letters

Plan A–N benefits, verbatim from medicare.gov
50 states + DC, with structural exceptions (MA / MN / WI)
Federal 30-day-look-back qualifying events surfaced
Free SHIP counselor referral above any broker option

The federal Medigap OEP is six consecutive calendar months, anchored to the first month the beneficiary is both age 65 and enrolled in Part B.

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Open the full decoder page →

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.

Your state may protect you beyond the federal floor

The federal 6-month window applies in every state, but four states (CT, ME, MA, NY) have continuous or annual guaranteed-issue, two states (CA, OR) have an annual birthday-rule switching window, and three states (MA, MN, WI) operate Medigap plan structures that don’t use the federal 10-letter system at all.

See all 50 states + DC →

Continuous or annual GI (CT, ME, MA, NY)
Birthday rule (CA, OR)
Structural exception — non-letter system (MA, MN, WI)
Federal-floor (default)

Ten federal Medigap plans, one frozen benefits matrix

Since the 1990 NAIC Medicare Supplement Standardization, every federal Medigap plan letter (A–N) covers a federally-frozen set of benefits. The matrix below is verbatim from medicare.gov. Plans C and F are closed to people newly Medicare-eligible on or after 2020-01-01 per MACRA 2015.

All 10 plan letters →

Federal Medigap plan-letter benefits matrix (Plans A–N, CMS-standardized).
Benefit	K	L	M	N
Part A coinsurance and hospital costs (up to an additional 365 days after Medicare benefits are used up)
Part B coinsurance or copayment	50%	75%		See note
Blood (first 3 pints)	50%	75%
Part A hospice care coinsurance or copayment	50%	75%
Skilled nursing facility care coinsurance	50%	75%
Part A deductible	50%	75%	50%
Part B deductible
Part B excess charges
Foreign travel emergency (up to plan limits)
Out-of-pocket limit (applies to Plans K and L only)

Reading the matrix: ✓ = the plan covers 100% of the federally-defined benefit; 50%/75% = the plan pays that share of the benefit; ✗ = the plan does not cover the benefit. Plans C and F are closed to people newly eligible for Medicare on or after 2020-01-01 per MACRA 2015 grandfathering. Massachusetts, Minnesota, and Wisconsin do not use the federal 10-letter system; see your state page for the state-specific Medigap structure.

2026-05-11medicare.gov — Compare Medigap Plan Benefits

Plan footnotes

1. Plan N · Part B coinsurance or copayment: Plan N pays 100% of the Part B coinsurance, except for a copayment of up to $20 for some office visits and up to a $50 copayment for emergency room visits that don't result in inpatient admission. (Verify CMS dollar amounts at annual review cron.)
2. Plan C · Part B deductible: Plans C and F are closed to new Medicare-eligible beneficiaries on or after 2020-01-01 per MACRA 2015. Beneficiaries first eligible for Medicare BEFORE 2020-01-01 may still purchase Plans C and F.
3. Plan F · Part B deductible: Plans C and F are closed to new Medicare-eligible beneficiaries on or after 2020-01-01 per MACRA 2015. Beneficiaries first eligible for Medicare BEFORE 2020-01-01 may still purchase Plans C and F.
4. Plan K · Out-of-pocket limit (applies to Plans K and L only): Plans K and L include an annual out-of-pocket limit. After the limit is met for the calendar year, Plan K (or L) pays 100% of covered services for the remainder of the year. For 2026, the Plan K limit is $8,000 and the Plan L limit is $4,000 (per CMS K & L Out-of-Pocket Limits Announcement, October 2025; statutory basis 42 U.S.C. § 1395ss(w)(2)).
5. Plan L · Out-of-pocket limit (applies to Plans K and L only): Plans K and L include an annual out-of-pocket limit. After the limit is met for the calendar year, Plan K (or L) pays 100% of covered services for the remainder of the year. For 2026, the Plan K limit is $8,000 and the Plan L limit is $4,000 (per CMS K & L Out-of-Pocket Limits Announcement, October 2025; statutory basis 42 U.S.C. § 1395ss(w)(2)).

Why MedigapWindow

Built like a public-health tool, not a broker funnel

Medicare.gov has the basics page but doesn’t compute your specific 6-month window from your DOB and Part B date. Broker funnels do compute it — but they bury your free SHIP counselor option and quote you only plans in their portfolio. We do the calculation in your browser, surface SHIP first, and cite the statute.

Calm precision, not panic copy

The federal 6-month OEP is real. It’s a calendar window, not a ticking bomb. We surface dates with statute pins and show next-step paths even after the window closes.

SHIP first, broker last

State SHIP counselors are free, federally-funded, and earn no commission. We surface them on every page, more prominently than any compensated broker referral. Why this matters.

Inputs stay in your browser

Your DOB, Part B date, state, and Medicaid status never leave your device. The OEP-decoder runs entirely client-side. No account, no email signup, no retargeting. Privacy details.

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

Free help · No cost · No commission · Federally funded

Talk to your state SHIP counselor

SHIP (State Health Insurance Assistance Program) is the federal Medicare benefits-counseling program. Every state has one. SHIP counselors are trained, federally funded volunteers. They are notbrokers. They earn no commission. They cannot sell you a plan. They’re available to help you understand your specific situation — your federal 6-month OEP timing, your state’s Medigap rules, your Plan F MACRA grandfathering status, and your federal guaranteed-issue protections.

National SHIP locator

1-877-839-2675

shiphelp.org — find your state’s SHIP program.