Do I Really Need Supplemental Insurance With Medicare?

Why Original Medicare Leaves a Gap

Original Medicare — Part A (hospital) and Part B (medical) — pays a large share of your covered care, but it was never designed to pay everything. The single most important fact to understand is this: Original Medicare has no annual out-of-pocket maximum. Once you have used your benefits, there is no dollar ceiling that stops your cost-sharing for the year, the way there is with most employer or marketplace plans.

In practice, that means even routine years carry real costs, and a serious illness can be open-ended. Supplemental coverage exists to close those gaps. The main paths are a Medigap (Medicare Supplement) policy, a Medicare Advantage plan that replaces how you get your benefits, or other secondary coverage such as retiree, employer, VA, or Medicaid benefits.

• Part A 2026 inpatient hospital deductible: $1,736 per benefit period — and it can apply more than once a year if a new benefit period begins.
• Part B 2026: a $283 annual deductible, then you generally pay 20% coinsurance of the Medicare-approved amount, with no annual limit.
• Original Medicare does not include routine prescription drug coverage — that requires a separate Part D plan.

What You'd Owe in 2026 Without Supplemental Coverage

These are the verified 2026 cost-sharing amounts under Original Medicare. They show why a single hospital stay or an expensive chronic condition can add up quickly when you carry no secondary coverage.

• Part B standard premium: $202.90/month; annual deductible $283; then typically 20% coinsurance on covered services with no cap.
• Part A inpatient hospital: $1,736 deductible per benefit period (days 1–60); $434/day for days 61–90; $868/day for each lifetime reserve day (60 total over your lifetime).
• Skilled nursing facility: $0 for days 1–20, then $217/day for days 21–100 in a benefit period.
• Part A is premium-free if you have 40+ work quarters; otherwise it costs $311/month (30–39 quarters) or $565/month (fewer than 30 quarters).
• Prescription drugs: only covered if you add Part D, which in 2026 caps your out-of-pocket spending on covered drugs at $2,100 for the year.

Three Ways People Fill the Gap

There is no one-size-fits-all answer. Most beneficiaries choose one of these routes, and the right choice depends on your health, budget, travel habits, and whether you value predictable bills or lower premiums.

• Medigap (Medicare Supplement): private policies, standardized by letter (e.g., Plan G, Plan N), that pay some or all of Original Medicare's deductibles and coinsurance. Coverage is consistent across insurers for a given letter, but premiums and availability vary by company and state. Medigap does not include drug coverage, so you typically add a separate Part D plan.
• Medicare Advantage (Part C): private plans that bundle Parts A and B, usually include Part D, and by law must have an annual out-of-pocket maximum. In exchange you generally use the plan's provider network and rules. You cannot have both Medigap and Medicare Advantage at the same time.
• Other secondary coverage: employer or union retiree plans, COBRA, VA benefits, TRICARE, or Medicaid may already fill the gaps. If you have this, you may not need to buy additional supplemental coverage — confirm how your plan coordinates with Medicare before deciding.

When You Might Not Need to Buy More

Supplemental insurance is valuable for most people, but not everyone needs to buy a separate Medigap or Advantage plan. You may already be covered, or your situation may make a different path the better fit.

Review your existing benefits first. If you have qualifying employer, retiree, VA, or Medicaid coverage, adding a Medigap policy on top can mean paying for protection you already have. If you choose Medicare Advantage instead of Medigap, the plan's built-in out-of-pocket maximum already provides the catastrophic protection that Original Medicare lacks.

• You have retiree or employer coverage that coordinates with Medicare and limits your costs.
• You qualify for Medicaid or a Medicare Savings Program that helps pay your cost-sharing.
• You choose a Medicare Advantage plan, which includes a yearly out-of-pocket cap — though benefits, networks, and costs vary by plan.
• You're a veteran whose VA benefits meet your needs (though many still take Part B for care outside the VA).

Why Timing Matters for Medigap

If you think a Medigap policy is right for you, when you buy matters as much as whether you buy. Your best opportunity is the one-time, 6-month Medigap Open Enrollment Period that starts the first month you are both 65 or older and enrolled in Part B.

During that window you have guaranteed issue rights: insurers cannot use medical underwriting to deny you, delay coverage, or charge you more because of pre-existing conditions. After it ends, in most states insurers can use medical underwriting — meaning they may refuse you or raise your price based on your health, unless you have a separate guaranteed issue right. This is why some healthy people who skip Medigap early find it harder or costlier to add later.

• Medigap Open Enrollment is a one-time 6-month period — it does not repeat each year like the fall Open Enrollment Period.
• Delaying Part B without other creditable coverage can trigger a permanent Part B late-enrollment penalty of 10% for each full 12-month period you could have had it.
• Delaying Part D without creditable drug coverage can trigger a lifelong penalty of 1% of the $38.99 national base premium for each full month you went without it.

If You're a Higher Earner: IRMAA

Your income can change the math. The Income-Related Monthly Adjustment Amount (IRMAA) adds a surcharge to your Part B and Part D premiums if your modified adjusted gross income (MAGI) is above the threshold. For 2026, IRMAA generally applies when MAGI from your 2024 tax return exceeds $109,000 if single or $218,000 if married filing jointly.

These surcharges raise your baseline Medicare costs regardless of which supplemental route you pick, so factor them into your budget when weighing a Medigap premium against a Medicare Advantage plan.

• Part B with IRMAA in 2026 ranges from $284.10 up to $689.90/month depending on income.
• Part D IRMAA adds a surcharge of $14.50 to $91.00/month on top of your drug plan's premium.
• IRMAA is based on income from two years prior; if your income dropped due to a life-changing event, you can ask Social Security to reconsider.