To cancel Medicare Part B, you file form CMS-1763 with the Social Security Administration, either in person at a local office or by mail, and complete a required interview confirming you understand what you’re giving up. Learning how to cancel Medicare Part B is the easy part. The hard part is timing: cancel while you have the wrong kind of other coverage, and you’ll owe a 10% premium surcharge for every full year you went without Part B, every month, for the rest of your life. The standard Part B premium is $202.90 per month in 2026, so that penalty compounds into real money.1Centers for Medicare & Medicaid Services. 2026 Medicare Parts A and B Premiums and Deductibles
Filing Form CMS-1763
The cancellation form is CMS-1763, “Request for Termination of Premium Part A, Part B, or Part B Immunosuppressive Drug Coverage.” Download it from the CMS website or pick up a copy at a Social Security office. It asks for your name, Medicare number, address, phone number, and the date you want coverage to end.2Centers for Medicare & Medicaid Services. Form CMS-1763 – Request for Termination of Premium Part A, Part B, or Part B Immunosuppressive Drug Coverage
Sign the form and submit it to your local Social Security office by mail or in person.2Centers for Medicare & Medicaid Services. Form CMS-1763 – Request for Termination of Premium Part A, Part B, or Part B Immunosuppressive Drug Coverage Social Security will usually require a personal interview, typically by phone, to confirm you understand the consequences of dropping coverage.3Social Security Administration. How Do I Terminate My Medicare Part B (Medical Insurance) The interviewer walks through the penalty rules and asks about the coverage you’ll have in place instead. Treat that conversation as your last check on the decision.
When Coverage Actually Ends
Your Part B doesn’t stop the day you file. Federal law sets the termination date at the last day of the month after the month Social Security receives your request.4Office of the Law Revision Counsel. 42 USC 1395q – Coverage Period File on June 15, and your coverage runs through July 31.5Medicare. How to Drop Part A and Part B You owe the premium for every month you’re covered, including that last one.
If your premium comes out of your Social Security check, deductions stop once the termination processes and the final month is paid. Expect a short lag. One extra deduction after filing is normal and should correct itself in a payment cycle or two.
When It’s Safe to Cancel
There is essentially one scenario where dropping Part B carries no financial risk: you or your spouse are actively working, and that employer provides group health insurance through a company with 20 or more employees.6Centers for Medicare & Medicaid Services. Small Employer Exception In that setup, the employer plan pays first, and you don’t need Part B while you’re on the job. When the employment or the coverage ends, an eight-month Special Enrollment Period lets you pick Part B back up without penalty.7Medicare. Working Past 65
The word “active” carries the whole rule. The coverage has to come from current employment.
The Small Employer Trap
If your employer has fewer than 20 full-time and part-time employees combined, Medicare is your primary insurer, not the employer plan.6Centers for Medicare & Medicaid Services. Small Employer Exception Cancel Part B in that situation and you’re left with a group plan built to pay second, which may cover far less than you assume. The gap still counts toward the late enrollment penalty, because Medicare was supposed to be primary the whole time.
One exception: if that small employer participates in a multi-employer plan where at least one participating employer has 20 or more employees, the standard Medicare Secondary Payer rules apply and the group plan pays first.6Centers for Medicare & Medicaid Services. Small Employer Exception Before you file CMS-1763, confirm employer size with your benefits administrator.
If you’re under 65 and on Medicare through disability, the threshold is 100 or more employees before the group plan is primary.8Centers for Medicare & Medicaid Services. Medicare Secondary Payer Disability Below that, Medicare is primary and Part B should stay.
What Doesn’t Qualify
These common types of coverage do not protect you from the late enrollment penalty, and dropping Part B while relying on them creates a gap you’ll pay for later:7Medicare. Working Past 65
- Retiree health benefits from a former employer
- COBRA continuation coverage
- Individual marketplace plans
- Veterans Administration benefits
If your only coverage is on that list, keep Part B.
What You Lose Along With Part B
Canceling Part B has knock-on effects beyond outpatient coverage.
Medicare Advantage plans (Part C) require enrollment in both Part A and Part B. Cancel Part B and you lose your Advantage plan automatically. Medigap supplemental policies work the same way; they sit on top of Original Medicare and cannot exist without both parts underneath them.
The Medigap issue that catches people off guard is guaranteed issue. Federal law gives you a one-time, six-month open enrollment window when you first sign up for Part B at 65, and during that window Medigap insurers must sell you a policy regardless of your health history. Cancel Part B and re-enroll later, and you generally don’t get a new open enrollment period. In most states, insurers can reject your application or charge more based on pre-existing conditions. For anyone with chronic health issues, that consequence can outlast the reason you canceled in the first place.
Part D prescription drug coverage requires enrollment in Part A or Part B.9Centers for Medicare & Medicaid Services. Medicare Prescription Drug Eligibility and Enrollment Since most people have premium-free Part A through their work history, dropping Part B alone won’t cost you Part D.
HSA Contributions After Cancellation
If you’re canceling because you’ve returned to work and want to fund a Health Savings Account, know the IRS rule: you cannot contribute to an HSA during any month you’re enrolled in Medicare.10Internal Revenue Service. Publication 969 – Health Savings Accounts and Other Tax-Favored Health Plans Contributions can resume the first full month after your Part B termination takes effect.
For 2026, HSA contribution limits are $4,400 for individual coverage and $8,750 for family coverage.11Internal Revenue Service. Revenue Procedure 2025-19 – HSA Contribution Limits If Part B ends midyear, you can only contribute the prorated amount for the months you weren’t on Medicare. Anything above that is an excess contribution subject to a 6% tax. Get the calendar right.
The Late Enrollment Penalty
If you cancel Part B without qualifying employer coverage and later want it back, you pay an extra 10% on top of the standard premium for every full 12-month period you went without.12Medicare. Avoid Late Enrollment Penalties The penalty is permanent. It applies every month you have Part B, which for most people means the rest of life.
An example. Cancel at 66, re-enroll at 69, and the gap is 36 months. Only full 12-month periods count, so that’s three years and a 30% penalty. On the 2026 premium of $202.90, that’s an extra $60.87 per month. Over 20 years, the penalty alone costs more than $14,600, before any future premium increases. The percentage stays fixed as the base premium rises, so the dollar cost grows each year.
Getting Part B Back
How you re-enroll depends on why you left.
If you canceled because you had qualifying employer coverage, you get an eight-month Special Enrollment Period starting when the employment ends or the coverage stops, whichever comes first.7Medicare. Working Past 65 Sign up in that window, no penalty. Miss it, and the penalty clock starts from the month after the SEP ends. Eight months goes fast during a job transition. Put the deadline on your calendar the day the job ends.
If you miss the SEP, or you canceled without qualifying coverage to begin with, your only path back is the General Enrollment Period, January 1 through March 31 each year. Coverage starts the month after you sign up, so you could wait months for protection.13Medicare. When Does Medicare Coverage Start During that stretch you’re uninsured for everything Part B would have covered: doctor visits, outpatient procedures, lab work, preventive screenings. The late enrollment penalty applies on top of the standard premium once coverage starts.
The General Enrollment Period is the worst-case path back into Part B. If you’re heading toward it, something went wrong in the cancellation planning. The whole point of understanding these rules before you file is to make sure you never need it.