Medigap Plans Explained: Supplementing Original Medicare Coverage

Medigap (Medicare Supplement Insurance) fills cost-sharing gaps in Original Medicare (Parts A & B). Standardized plans (A–N) offer predictable benefits across insurers—only premiums differ.

What Original Medicare Doesn't Cover (The "Gaps")

• Part A deductible ($1,632 per benefit period in 2024)
• Part A coinsurance (days 61–90: $408/day; days 91–150: $816/day "lifetime reserve")
• Part B deductible ($240/year in 2024)
• Part B coinsurance (20% of Medicare-approved amount)
• Part B excess charges (up to 15% above Medicare rate from non-participating providers)
• Foreign travel emergency care (80% after $250 deductible, lifetime $50,000 limit)
• First 3 pints of blood

Standardized Medigap Plans (A, B, C, D, F, G, K, L, M, N)

Key: All plans with the same letter offer identical benefits regardless of insurer. Only premiums differ.

Benefit	A	B	C	D	F	G	K	L	M	N
Part A coinsurance + hospital reserve	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
Part B coinsurance/copay	✓	✓	✓	✓	✓	✓	50%	75%	✓	✓*
Blood (first 3 pints)	✓	✓	✓	✓	✓	✓	50%	75%	✓	✓
Part A hospice coinsurance	✓	✓	✓	✓	✓	✓	50%	75%	✓	✓
Skilled nursing facility coinsurance			✓	✓	✓	✓	50%	75%	✓	✓
Part A deductible		✓	✓	✓	✓	✓	50%	75%	50%	✓
Part B deductible			✓		✓
Part B excess charges					✓	✓
Foreign travel emergency			80%	80%	80%	80%			80%	80%
Out-of-pocket limit (2024)	None	None	None	None	None	None	$7,060	$3,530	None	None

*Plan N: Copays up to $20 for office visits, $50 for ER (waived if admitted)

Important Plan Notes

• Plans C & F: Not available to new Medicare beneficiaries (enrolled after 1/1/2020) due to MACRA law eliminating Part B deductible coverage.
• Plan G: Most popular comprehensive alternative to F (covers everything except Part B deductible).
• High-Deductible G/F: Lower premiums, pay $2,800 deductible (2024) before coverage starts.
• Plans K & L: Cost-sharing plans (50%/75%) with out-of-pocket limits.

Enrollment Rules

• Medigap Open Enrollment: 6 months starting the month you're 65+ AND enrolled in Part B. Guaranteed issue, no medical underwriting, best prices.
• After Open Enrollment: Medical underwriting applies (except guaranteed issue rights: losing other coverage, moving, plan termination, etc.)
• No annual enrollment period—can apply anytime, but may be denied or charged more based on health.
• Must have Parts A & B to purchase.

Cost Considerations

• Premiums vary widely: Same Plan G ranges $100–$300+/month by company, region, age, gender, tobacco.
• Pricing methods: Community-rated (same for all), Issue-age-rated (based on age at purchase), Attained-age-rated (increases with age).
• No network restrictions: Any Medicare provider nationwide.
• Does NOT include Part D (drugs)—separate enrollment needed.

Medigap vs. Medicare Advantage (Part C)

Feature	Medigap + Original Medicare	Medicare Advantage
Provider choice	Any Medicare provider (96%+)	Network restricted (HMO/PPO)
Referrals	Not needed	Often required (HMO)
Out-of-pocket predictability	High (low/no cost-sharing)	Variable (copays, coinsurance, MOOP)
Drug coverage	Separate Part D plan	Usually included (MAPD)
Extra benefits	None	Dental, vision, hearing, fitness
Travel coverage	Nationwide + foreign emergency	Usually limited to network/emergency

Decision Framework

1. Assess health needs & budget.
2. Compare Plan G vs. High-Deductible G vs. N premiums.
3. Check insurer financial ratings (A.M. Best, Weiss).
4. Consider future health changes (guaranteed renewability).
5. Enroll during Open Enrollment for best access/pricing.

Resource: Medicare.gov Plan Finder for local premium comparisons.