Medicare 2026

High-Deductible Medigap Plan G: How It Works

Medigap, also called Medicare Supplement Insurance, helps pay the out-of-pocket costs Original Medicare leaves behind — things like coinsurance and copayments on Part A and Part B services. Standard Plan G is one of the more comprehensive Medigap options available to people newly eligible for Medicare today. High-deductible Plan G (often shortened to HDG) is a lower-premium version of the same plan: you agree to pay a set amount out of pocket each year before the policy starts filling in those gaps.

This explainer walks through how HDG works at the federal level, what the deductible looks like for 2026 and 2027, and where it fits alongside Part D and your other Medicare decisions.

What HDG actually covers

Once you've met the annual deductible, high-deductible Plan G pays the same cost-sharing that standard Plan G pays. That includes the Part A hospital coinsurance and most Part A costs, the Part B coinsurance or copayment, the first three pints of blood, hospice care coinsurance, skilled nursing facility coinsurance, and foreign travel emergency care up to plan limits. The one notable gap, as with standard Plan G sold to people newly eligible today, is the Part B deductible — that's something you pay yourself before Medicare starts paying its share of outpatient costs.

The federal deductible amount for high-deductible Plans F and G is set each year by CMS. For 2026 it is $2,950. For 2027 it is $3,050 (CMS announced the 2027 figure in October 2026). Spending that counts toward the HDG deductible generally includes the Medicare-covered cost-sharing the policy would otherwise pay for you. Once you reach that amount in a calendar year, the plan takes over the covered cost-sharing for the rest of the year.

How HDG differs from standard Plan G

The benefit design is identical after the deductible — the trade-off is purely about timing and premium.

• Standard Plan G: higher monthly premium, lower out-of-pocket exposure during the year (just the Part B deductible before Medicare and the plan start sharing costs).
• High-deductible Plan G: generally lower monthly premium, but you pay cost-sharing until you reach the annual HDG deductible.

Premiums for either version vary by insurance company, your age, where you live, tobacco use, and how the carrier rates its policies, so there is no single national figure. What stays the same nationally is the standardized benefit structure and the HDG deductible amount.

Who can buy it, and when

High-deductible Plan G has been offered since January 1, 2020. It was created after high-deductible Plan F was closed to people newly eligible for Medicare on or after that date. If you became eligible for Medicare before January 1, 2020, you may still be able to buy high-deductible Plan F; if you became eligible on or after that date, HDG is the high-deductible Medigap option available to you.

The strongest consumer protections for buying any Medigap policy, including HDG, apply during your Medigap Open Enrollment Period — the six-month window that starts the month you're 65 or older and enrolled in Part B. During that window, insurers generally can't deny you coverage or charge more because of health conditions. Outside it, in most of the country, medical underwriting may apply. The rules on guaranteed-issue rights are set at the federal level, with some state variations; Medicare.gov has the current details.

Don't forget Part D

Medigap plans — including HDG — do not cover outpatient prescription drugs. If you want drug coverage, you enroll in a stand-alone Part D plan.

A few 2027 Part D numbers worth knowing as you plan:

• The annual out-of-pocket cap on covered drugs is $2,400 in 2027 (it is $2,100 in 2026).
• The most any Part D plan may charge as a plan deductible in 2027 is $700.
• The base beneficiary premium used in the late-enrollment penalty calculation is $41.33 in 2027; actual plan premiums are set plan by plan.

Annual Enrollment runs October 15 – December 7, 2026 for coverage that starts January 1, 2027. This is the main window for changing Part D plans.

People with Medicaid or Extra Help have additional flexibility: since 2025, there is a monthly Special Enrollment Period to move from Medicare Advantage to Original Medicare with a stand-alone Part D plan, or to switch stand-alone Part D plans. Full-benefit dual-eligible individuals can also join an integrated Dual Eligible Special Needs Plan (D-SNP) in any month.

HDG vs. Medicare Advantage: a neutral note

Some readers weigh Original Medicare plus a Medigap policy (like HDG) and a Part D plan against a Medicare Advantage plan. These are different structures with different trade-offs. Original Medicare plus Medigap generally gives nationwide access to any provider who accepts Medicare and predictable cost-sharing after the deductible, but you pay separate premiums for Medigap and Part D. Medicare Advantage typically bundles medical and drug coverage, often with networks and prior authorization, and may include extras not found in Original Medicare. Neither is "better" in the abstract — it depends on your providers, prescriptions, travel patterns, budget, and how you feel about predictability versus bundled extras.

A few other 2027 context items

The Social Security Administration announced a 3.6 percent cost-of-living adjustment (COLA) for benefits payable beginning January 2027. The 2027 Part B standard premium, Part B deductible, and IRMAA income brackets had not yet been announced at the time of writing — CMS announces those in the fall, typically November. Check Medicare.gov once they're posted.

Where to go next

For the official rules on Medigap, including how standardized plans like HDG work and the enrollment protections in your situation, visit Medicare.gov or call 1-800-MEDICARE (1-800-633-4227), available 24/7. This article is educational and does not rank or recommend any specific plan.