Compare your real Medigap costs: Plan G, Plan N & High-Deductible Plan G

How each plan pays a claim. All three plans sit on top of Original Medicare, which pays 80% of the Medicare-approved amount for Part B services once the Part B deductible is met, and covers Part A hospital costs after the Part A deductible — that doesn't change based on which Medigap plan you own.

• Plan G: you pay the Part B deductible only. Once that's met, Plan G picks up the rest — your 20% Part B coinsurance, the Part A deductible, and Part B excess charges — 100%, for the rest of the year.
• Plan N: you pay the Part B deductible, plus a small copay (default $20) on office and urgent care visits. Everything else — including the Part A deductible and your 20% Part B coinsurance outside those copay visits — is covered. Plan N does not cover Part B excess charges, which this tool doesn't model since they're provider-dependent.
• High-Deductible Plan G: behaves exactly like traditional Medicare cost-sharing until the HDG deductible is satisfied. You pay the Part B deductible, then 20% coinsurance on Part B claims (Medicare is still paying the other 80% the entire time — you're never billed the full charge), plus the Part A deductible if hospitalized — all of it accumulating toward the annual HDG cap. Once your accumulated cost-sharing hits that cap, HDG converts to acting exactly like standard Plan G for the rest of the year: 100% coverage, $0 more out of pocket.

Why the numbers change year to year. Six separate figures compound annually, each at its own rate (all editable above):

• Plan G & Plan N premiums — default 10%/yr
• High-Deductible Plan G premium — default 10%/yr (lower this to model HDG premiums rising more slowly)
• Part B premium / IRMAA — default 0%/yr (recent actual increases: 6% in 2025, ~10% in 2026)
• High-Deductible Plan G annual cap — default 3%/yr, tied to CPI-U by law (history: $2,370 in 2021 → $2,950 in 2026)
• Part B deductible — default 7%/yr (history: $203 in 2021 → $283 in 2026, though it fell slightly in 2023)
• Part A deductible — default 3%/yr (history: $1,600 in 2023 → $1,736 in 2026)
• Medicare-approved service costs (office visit, urgent care, surgery, PT) — default 4%/yr, a general medical-cost-trend estimate

The Plan N copay ($20 default) is held flat since it's a standardized policy term, not a figure CMS adjusts annually.

The "Realistic Mix" timeline. Rather than assuming every year looks identical, this models years 1, 2, 4, 5, 6, 8, 9, and 10 as typical care years, year 3 as a frequent-care year, and year 7 as a major medical event — one heavier stretch and one genuine catastrophic year over a decade, which is closer to how care actually falls for most people than assuming either constant good health or constant crisis.

Sources: CMS 2026 Medicare Parts A & B Premiums, Deductibles, and IRMAA fact sheets (cms.gov); CMS High-Deductible Plan F/G/J Deductible Announcements 2021–2026. Medicare-approved service cost estimates are general planning figures, not published CMS fee schedule line items, and should be treated as illustrative.