What Percent of Americans Over 65 Are on Medicare?

According to recent U.S. Census Bureau data, nearly 99% of Americans aged 65 and older are covered by Medicare. This overwhelmingly high enrollment rate reflects Medicare's fundamental role as the cornerstone of healthcare for the vast majority of the senior population, addressing the question, what percent of Americans over 65 are on Medicare.

Quick Summary

Approximately 99% of Americans aged 65 and older are enrolled in Medicare, with slight variations due to eligibility requirements, work history, and legal residency status.

Key Points

• Near-Universal Enrollment: Approximately 99% of Americans aged 65 and older are enrolled in Medicare, according to U.S. Census data.

• Not a Perfect 100%: The small portion not enrolled is often due to insufficient work history for premium-free Part A, legal residency issues, or continued employer coverage.

• Plan Options: Seniors can choose between Original Medicare (Parts A & B) and Medicare Advantage (Part C), which is offered by private companies.

• Supplemental Coverage: Many with Original Medicare purchase supplemental plans like Medigap or rely on Medicaid to cover gaps in coverage.

• Medicare Advantage Growth: Enrollment in private Medicare Advantage plans has surpassed 50% of the eligible population, with continued growth expected.

• Eligibility Requirements: Core eligibility depends on age, U.S. residency, and a sufficient work history with Medicare tax contributions.

The Near-Universal Coverage of Seniors

Medicare, established in 1965, serves as the primary health insurance for most Americans aged 65 and over. Its high enrollment rate underscores its vital role in the U.S. healthcare system.

Why Isn't the Coverage Exactly 100%?

While most seniors are covered, a small percentage are not due to several factors:

• Work History: To qualify for premium-free Medicare Part A, individuals typically need at least 10 years of work history where Medicare taxes were paid. Those without sufficient history can buy Part A, but not all do.
• Residency: Eligibility requires U.S. citizenship or at least five years of legal residency.
• Employment Coverage: Some seniors remain on employer-sponsored health plans, though many still enroll in premium-free Part A.
• Personal Preference: A small number of eligible individuals may opt out for other reasons.

Understanding the Components of Medicare

Medicare coverage is provided through either Original Medicare or a Medicare Advantage plan.

Original Medicare vs. Medicare Advantage

Choosing a plan involves considering how benefits are received. Here's a comparison:

Feature	Original Medicare (Part A & B)	Medicare Advantage (Part C)
Administration	Government-run	Private insurance companies approved by Medicare
Provider Network	Generally allows for any doctor or hospital that accepts Medicare	Typically has a network of providers, like an HMO or PPO
Referrals	No referrals needed for specialists	May require referrals to see a specialist, especially with HMO plans
Prescription Drugs	Not included; requires a separate Part D plan	Usually includes prescription drug coverage (MA-PD)
Additional Benefits	No routine vision, dental, or hearing coverage	Often includes extra benefits like vision, dental, hearing aids, and gym memberships
Out-of-Pocket Costs	No annual out-of-pocket maximum; supplemental insurance (Medigap) often needed	Includes an annual out-of-pocket maximum to protect against high costs

Supplemental Coverage Options

Original Medicare beneficiaries often seek additional coverage through:

• Medigap Policies: Private plans that help cover costs not paid by Original Medicare.
• Medicaid: A state and federal program assisting low-income individuals, which can cover Medicare costs for dual-eligible individuals.
• Employer/Union Plans: Some retirees have health benefits from former employers or unions that supplement Medicare.

Enrollment Trends and the Future

The percentage of seniors on Medicare is stable, but plan choices are evolving. Medicare Advantage enrollment now covers over 50% of eligible individuals and is growing. This shift is influenced by bundled benefits and out-of-pocket spending limits. As the senior population increases, total Medicare enrollment will rise, maintaining its high coverage rate among older Americans. For more detailed information, consult research from the Kaiser Family Foundation (KFF). Understanding these dynamics is crucial for senior care and retirement planning.

Frequently Asked Questions

Does everyone automatically get Medicare at 65?

No, enrollment is not automatic for everyone. While those already receiving Social Security benefits are automatically enrolled in Parts A and B, others must actively sign up during their Initial Enrollment Period to avoid penalties.

What is the primary reason some seniors aren't on Medicare?

One of the most common reasons is not having paid Medicare taxes for enough quarters (usually 40) to qualify for premium-free Part A. Others may have different healthcare coverage through employment or are not eligible due to legal residency requirements.

Are older Americans with disabilities also covered by Medicare?

Yes, Medicare is also available to younger people with disabilities, End-Stage Renal Disease, or ALS. In fact, as of August 2025, a small percentage of total Medicare enrollees are under 65.

How do seniors choose between Original Medicare and Medicare Advantage?

The choice depends on several factors, including cost, provider networks, extra benefits, and prescription drug coverage. Original Medicare offers more flexibility in choosing providers, while Medicare Advantage plans often include additional benefits and an out-of-pocket maximum.

What happens if a senior is still working after age 65?

Seniors who continue to work often have employer-sponsored health insurance. They can typically delay enrolling in Medicare Part B to avoid paying premiums while still enrolling in premium-free Part A. A Special Enrollment Period allows them to sign up later without penalty.

Do all Medicare plans cover prescription drugs?

No. Original Medicare (Part A and B) does not include prescription drug coverage. Beneficiaries must enroll in a separate Part D plan. However, most Medicare Advantage (Part C) plans, known as MA-PDs, include this coverage as a bundled benefit.

Where can seniors get help with Medicare costs?

Low-income seniors who meet specific criteria may be eligible for assistance from Medicaid, which can help pay for Medicare premiums and other costs. There are also Medicare Savings Programs available through state and federal programs.