Medicare is frequently discussed as one big system, but in reality, most people only ever deal with specific segments of the program depending on their needs and preferences.
Medicare is broken down into four major “Parts,” each of which has a specific coverage universe, rules, and costs. Depending on your choices, you might go your entire life without really interacting with one or more of these Parts.
But I’ll try to help you understand each aspect of Medicare with my Medicare “Parts” series.
Today, I’m going to talk specifically about Medicare Part B, which is often discussed in tandem with Medicare Part A. I’ll explain what it covers, its costs, when you should sign up, and how it’s related to Part A.
The information and analysis contained within this article appears for your consideration, but it does not constitute individualized financial advice. Always act at your own discretion.
What Does Medicare Part B Cover?
Medicare Part B is generally considered to be “medical insurance,” which has two blanket-coverage areas: medically necessary services and preventative services. This includes things like:
- Ambulance services
- Chemotherapy
- Doctor visits (included check-ups)
- Durable medical equipment (DME)
- Mental health and substance-use disorder treatment
- Physical therapy
- Preventative vaccines
- Tests such as X-rays, CT scans, MRIs, and more
What Is Original Medicare?
Consider a set of twins named Ashley and Bonnie. Sometimes, a person may talk just about Ashley. Other times, just Bonnie. When discussing the pair, people may simply say “the twins.” In this analogy, “the twins” would be Original Medicare.
Original Medicare is composed of Parts A and B:
- Part A is broadly known as “hospital insurance,” covering people’s most critical healthcare needs.
- Part B tends to cover almost everything else, which is why people typically enroll in both Parts A and B together.
Parts A and B don’t cover most prescription drugs, which is what Part D is for. So Original Medicare is frequently paired with Part D. And the remaining segment, Part C? Well, it’s more of a private-market substitute for Parts A and B (and sometimes Part D, too).
You can learn about how all the different Parts interact in my primer on Medicare coverage.
Related: 10 Things Original Medicare Doesn’t Cover
How Much Do Medicare Part B Premiums Cost?
Medicare Part B premiums are determined annually in accordance with provisions in the Social Security Act. For the majority of people, the government covers 75% of the Part B premium and the other 25% is paid by the beneficiary.
For 2026, the standard monthly Part B premium that plan holders pay was set to $202.90 if their modified adjusted gross income (MAGI) listed from two years prior was as follows:
- Individuals or married people filing separately: $109,000 or less
- Married filing jointly: $218,000 or less
What happens if your MAGI is higher? In that situation, an income-related monthly adjustment amount (IRMAA) applies. This is uncommon, though. Right now, only about 8% of Plan B enrollees pay an increased premium.
But, with a high enough IRMAA, a person could be responsible for as much as 85% of their Part B premium. For 2026, the monthly premium that a plan holder could pay maxes out at $689.90. That maximum premium applies to the following groups:
- Individuals with MAGI of at least $500,000
- Married people filing jointly with MAGI of at least $750,000
- Married people filing separately with MAGI of at least $391,000
Premiums are different for beneficiaries with immunosuppressive drug coverage (Medicare Part B-ID). Currently, Part B-ID premiums begin at $121.60 for the following:
- Individuals or married people filing separately with MAGI of $109,000 or less
- Married people filing jointly with MAGI of $218,000 or less
This number maxes out at $608.10 if any of the following apply:
- Individuals with MAGI of at least $500,000
- Married people filing jointly with MAGI of at least $750,000
- Married people filing separately with MAGI of at least $391,000
Related: Health Care Costs in Retirement [Amounts & Types to Expect]
What If I Can’t Afford My Part B Premiums?
During periods of financial hardship, lower Part B premiums could offer some-much needed relief. A few ways to get there?
Qualified Medicare Beneficiary (QMB) Program
One possible pathway to reduced premiums is the Qualified Medicare Beneficiary (QMB) Program.
If you’re eligible for QMB, you get assistance for your Part A and Part B premiums. Additionally, Medicare providers cannot bill for Parts A and B copayments, coinsurance, and deductibles for Medicare-covered items and services.
Any Medicaid copayments could still apply, though. To qualify, your monthly income must be at or below the annual federal poverty level.
Note: Individual states can set their own thresholds.
Specified Low-Income Medicare Beneficiary (SLMB) Program
Another option to look into is the Specified Low-Income Medicare Beneficiary (SLMB) Program, which specifically helps people pay for Part B premiums.
Similar to the QMB program, there are federal income limits, but the limits are a bit higher in Alaska and Hawaii, and other states may allow you to qualify with a higher income or resource limit. Contact your state to find out your program’s details.
Qualifying Individual (QI) Program
The Qualifying Individual (QI) Program can also help beneficiaries with Part B premiums.
To qualify for the program, you need to have both Parts A and B. You also need to meet income and resource limits, which like the aforementioned programs can vary depending on your state of residence. You also must reapply every year.
People can only have QI if they don’t qualify for any other Medicaid coverage or benefits, but they can still be eligible for other Medicare Savings Programs (MSPs).
Related: Medicare FAQs: Your Questions Answered
What About Deductibles and Coinsurance?
Like Part B premiums, the deductibles and coinsurance rates are also determined every year according to provisions in the Social Security Act.
For 2026, the annual deductible for all Medicare Part B beneficiaries was set to $283. This is the same for all income levels.
Related: 7 Advantages of Medicare Advantage
Typically, coinsurance is 20% of the total cost for every Medicare-covered service or item after meeting the deductible.
Let’s say you hadn’t touched your deductible yet, then had a medical expense of $1,200. You would owe the $283 deductible, then 20% of the remaining $917 ($183.40) for a total of $466.40. If your deductible was already depleted, you would simply owe 20% of $1,200 ($240).
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When Do I Sign Up for Medicare Part B?
If you want to apply for age-based Medicare Part B, the three types of enrollment periods are the Initial Enrollment Period (IEP), Special Enrollment Period (SEP), and General Enrollment Period (GEP):
- IEP: Your Initial Enrollment Period depends on your birthday. It begins three months before you turn 65 and ends three months after the month you turn 65. For instance, if your birthday is July 12, your IEP starts April 1 and ends on Oct. 31 in the year you turn 65. However, there’s an exception for people whose birthday falls on the first of the month: Your IEP starts four months before you turn 65 and ends two months after the month you turn 65. Either way, you still get a seven-month period in which to enroll.
- SEP: If you miss your IEP, you may still be eligible for a Special Enrollment Period. This is a one-time enrollment period that can be triggered by certain events, such as losing Medicaid coverage, dropping out of an employer plan, or being released from incarceration. There are no penalties for eligible people who sign up during a SEP.
- GEP: People who miss their IEP and don’t qualify for a SEP can still sign up for Part B during the General Enrollment Period. This runs every year from Jan. 1 through March 31. Unfortunately, if you sign up during a GEP, you often have a late enrollment penalty, which typically permanently increases your Part B monthly premiums.
Related: Don’t Overpay for Medicare: How to Avoid the Late Enrollment Penalty
