Medicare Part B (Medical Insurance)

Medicare Part B is the medical insurance component of Original Medicare that covers outpatient care, doctor visits, preventive services, and medically necessary equipment. While Part A handles hospital stays, Part B covers the services you receive outside of a hospital setting.

Unlike Part A, Part B requires a monthly premium that most enrollees pay. The standard premium is income-based, with higher earners paying more through the Income-Related Monthly Adjustment Amount (IRMAA). Part B is optional but highly recommended, as late enrollment penalties apply if you delay without qualifying coverage.

Part B works alongside Part A to form Original Medicare. Many beneficiaries also purchase a Medicare Supplement (Medigap) policy to help cover Part B cost-sharing, including the annual deductible and 20% coinsurance.

What Part B Covers

• Doctor and specialist office visits
• Outpatient surgery and procedures
• Preventive services: annual wellness visits, flu shots, mammograms, colonoscopies, cardiovascular screenings
• Lab tests, X-rays, MRIs, CT scans, and diagnostic imaging
• Durable medical equipment (DME): wheelchairs, walkers, oxygen equipment, hospital beds
• Mental health services: outpatient therapy, psychiatry, partial hospitalization
• Ambulance services when medically necessary
• Outpatient physical, occupational, and speech-language therapy
• Some home health care services not covered by Part A
• Certain vaccines including COVID-19 and hepatitis B

What Part B Does NOT Cover

• Most dental care (cleanings, fillings, extractions, dentures)
• Routine eye exams and eyeglasses (except after cataract surgery)
• Hearing aids and exams for fitting hearing aids
• Cosmetic surgery
• Long-term care and custodial care
• Acupuncture (except for chronic low back pain)
• Most chiropractic services beyond spinal manipulation

Who Qualifies for Medicare Part B

Eligibility for Part B mirrors Part A eligibility:

• Adults aged 65 or older who are U.S. citizens or permanent legal residents for at least 5 continuous years
• Individuals under 65 receiving SSDI benefits for 24 months
• People with End-Stage Renal Disease (ESRD) or ALS

Unlike Part A, Part B is not automatic for everyone. If you are not yet receiving Social Security benefits at age 65, you must actively enroll. Part B enrollment is optional, but failing to enroll when first eligible can result in a permanent late enrollment penalty of 10% for each 12-month period you could have had Part B but did not.

2025/2026 Part B Costs

• Standard Monthly Premium: $185.00/month in 2025 (most enrollees)
• IRMAA Surcharge: Higher-income individuals pay $259.40 to $628.90/month based on modified adjusted gross income
• Annual Deductible: $257 per year in 2025
• Coinsurance: Typically 20% of Medicare-approved amounts after deductible
• No out-of-pocket maximum: Original Medicare has no annual cap on spending (Medigap or Advantage plans can help)

Premiums are usually deducted from Social Security benefits. Income thresholds for IRMAA are based on your tax return from two years prior. For example, 2025 premiums are based on 2023 income.

How to Enroll

If you are already receiving Social Security benefits, you are automatically enrolled in Part B when you turn 65. You can decline Part B if you choose.

• Initial Enrollment Period (IEP): 7-month window around your 65th birthday month
• General Enrollment Period (GEP): January 1 through March 31 each year, with coverage starting July 1. A late enrollment penalty may apply.
• Special Enrollment Period (SEP): If you have employer coverage through your or your spouse's current employment, you can enroll anytime while covered or within 8 months after coverage or employment ends (whichever comes first).

Enroll online at Medicare.gov, at ssa.gov, or by calling 1-800-MEDICARE (1-800-633-4227).

Pros

• Comprehensive outpatient and preventive care coverage
• Covers medically necessary doctor visits and specialist consultations nationwide
• Many preventive services covered at 100% with no cost-sharing
• Covers durable medical equipment and outpatient therapies
• Widely accepted by healthcare providers across the country

Cons

• Monthly premium required ($185/month in 2025, more for higher incomes)
• 20% coinsurance with no annual out-of-pocket maximum can lead to high costs
• Does not cover dental, vision, or hearing in most cases
• Late enrollment penalty is permanent and compounds over time
• IRMAA surcharges significantly increase costs for higher-income beneficiaries