What is Medigap?
A Medigap policy is supplemental insurance sold by private companies that helps pay for costs not covered by Original Medicare (Parts A and B). These costs include:
- Part A hospital deductible ($1,736 per benefit period in 2026)
- Part B coinsurance (the 20% you pay after your deductible)
- Part A coinsurance for extended hospital stays
- Skilled nursing facility coinsurance
- Part B excess charges (if a doctor charges more than the Medicare-approved amount)
- Foreign travel emergency care (up to plan limits)
Important: Medigap only works with Original Medicare. If you have a Medicare Advantage plan (Part C), you cannot use a Medigap policy. Medicare Advantage plans have their own built-in cost protections, including an annual out-of-pocket maximum.
Medigap plan letters
Medigap policies are standardized by the federal government and identified by letters. Each letter covers a specific set of benefits. Plans you can buy in Colorado include:
| Plan | Coverage highlights | Good to know |
|---|---|---|
| Plan G | Covers everything except the Part B deductible ($283 in 2026). The most comprehensive plan available to new enrollees. | Most comprehensive for people new to Medicare since 2020 |
| Plan N | Similar to Plan G but with small copays for some office visits (up to $20) and ER visits (up to $50). Lower premiums than Plan G. | Copays in exchange for lower premiums |
| High-deductible G | Same as Plan G but you pay a $2,950 deductible (2026) before the plan pays. Much lower premiums. | Pays only after the deductible |
| Plan A | Basic benefits — covers Part A coinsurance, Part B coinsurance, and first 3 pints of blood. No extras. | Basic benefits only |
Note: Plan F is no longer available to people who became newly eligible for Medicare on or after January 1, 2020. If you had Plan F before that date, you can keep it.
Medigap costs in Colorado
Medigap premiums vary significantly by insurance company, your age, your ZIP code, and your gender. In the Colorado Division of Insurance's Spring 2026 survey of companies, here are the monthly ranges for a 65-year-old non-smoker in Denver (ZIP 80202):
| Plan | Monthly range (age 65, ZIP 80202) |
|---|---|
| Plan G | $128 – $393/month |
| Plan N | $93 – $315/month |
| High-deductible Plan G | $46 – $85/month |
Source: Colorado Division of Insurance, Medigap Premium Charts, companies' answers to the Spring 2026 survey; rates may change at any time. Actual premiums depend on the carrier, your specific location in Colorado, and how the company prices its policies (issue-age, attained-age, or community-rated).
Pricing method matters: Issue-age policies base your premium on the age you were when you bought the policy — they don't increase as you age (though they may increase for inflation). Attained-age policies start lower but increase as you get older. Ask about the pricing method before you buy.
When to enroll
Your Medigap open enrollment period is the single most important window for purchasing a supplement policy. It starts the month you turn 65 and are enrolled in Part B, and lasts 6 months.
During this window:
- Insurance companies must sell you any Medigap policy they offer in Colorado
- They cannot charge more or deny coverage based on health conditions
- They cannot impose waiting periods for pre-existing conditions
After this window closes, Colorado insurers can use medical underwriting. This means they can deny you coverage or charge higher premiums based on your health history.
Colorado Medigap rules
Colorado follows federal Medigap standardization rules, meaning Plan G from one company covers exactly the same benefits as Plan G from another. The only differences are price and customer service.
- Under 65 with a disability — In Colorado, companies selling Medigap must also sell to people on Medicare under age 65 because of a disability. Premiums may be higher than at 65, and at 65 you get guaranteed issue rights again, so it pays to compare then. (Source: Colorado Division of Insurance Medigap guide, September 2026.)
- Guaranteed issue rights — Colorado provides guaranteed issue rights in certain situations, such as losing employer coverage or if your Medicare Advantage plan leaves your area.
- Free-look period — You have 30 days to review your new Medigap policy. If you're not satisfied, you can return it for a full refund.
- Rate increases — Insurers must file rate increases with the Colorado Division of Insurance. You can check filed rates at doi.colorado.gov.
Medigap vs. Medicare Advantage
This is one of the biggest decisions in Medicare. Here's a quick comparison:
| Medigap + Original Medicare | Medicare Advantage | |
|---|---|---|
| Monthly cost | Part B premium + Medigap premium + Part D premium | Part B premium + the plan's premium, if any |
| Out-of-pocket costs | Very low — Medigap covers most cost-sharing | Copays and coinsurance per service, up to annual max |
| Doctor choice | Any doctor that accepts Medicare, nationwide | Must use plan network (HMO) or pay more out-of-network (PPO) |
| Extra benefits | None — add dental, vision separately | Some plans offer dental, vision or hearing; extras vary by plan and county, may have limits and costs, and not every plan offers them |
| Best for | People who want predictable costs and broad provider choice | People who want lower premiums and extra benefits |
Frequently asked questions
What is Medigap Plan G?
Plan G covers everything except the Part B deductible ($283 in 2026), and it is the most comprehensive plan sold to people new to Medicare since 2020. Plan N has small copays for some visits in exchange for lower premiums.
How much does Medigap cost in Colorado?
In the Colorado Division of Insurance's Spring 2026 survey, Plan G for a 65-year-old non-smoker in Denver (ZIP 80202) ranged from $128 to $393 per month, and Plan N from $93 to $315. Rates vary by company, ZIP code, age, sex, and tobacco use.
When should I buy Medigap?
Your best window is the 6-month Medigap open enrollment period starting the month you turn 65 and enroll in Part B. During this period, insurers cannot deny you or charge more for health conditions.
