Direct answer: Medicare.gov says Part B late enrollment adds an extra 10 percent for each full 12-month period you could have signed up but did not. For most people that amount continues for as long as you have Part B. Part D adds 1 percent of the national base beneficiary premium for each month you went without creditable drug coverage, generally after a gap of 63 days or more. Part A has a separate rule for people who must buy Part A.
Where are these percentages published?
Use Medicare.gov: Avoid late enrollment penalties. That page states the Part B 10 percent per year rule, the Part D 1 percent per month rule, the 63-day creditable-coverage test, and the Part A 10 percent premium increase for people who must buy Part A, paid for twice the number of years they waited. This article does not repeat year-specific dollar premiums from the examples on that page because those amounts change.
When is there no Part B penalty?
Medicare.gov says you generally will not pay a Part B penalty if you qualify for a Special Enrollment Period or you enroll in a Medicare Savings Program. Current-employment group coverage is the common Special Enrollment Period. See signing up while still working. Marketplace coverage is not the same test. If you missed the Initial Enrollment Period and have no Special Enrollment Period, the General Enrollment Period is January 1 through March 31, coverage starts the month after you sign up, and a penalty may apply.
How is Part D different?
Part D looks at creditable prescription drug coverage. Medicare.gov says you generally will not pay a Part D penalty if you have creditable drug coverage or you qualify for Extra Help. If you go 63 days or more without Medicare drug coverage or other creditable coverage after you were eligible, a lifetime monthly penalty can apply after you join a drug plan. Ask your employer or union plan for its creditable-coverage notice each year and keep it.
Does Medigap have the same penalty?
No. Medigap does not use the Part B late enrollment percentage. Medigap has a federal six-month Open Enrollment Period starting when you are 65 or older and enrolled in Part B, plus other issue rights in some situations. Those rules are separate from Medicare Annual Enrollment. See Medicare plan-change windows and Medicare Advantage versus Medicare Supplement.
What should I do if I already have a penalty on my bill?
The premium notice from Medicare or the drug plan should show the penalty line. If you believe you had creditable coverage or a Special Enrollment Period, follow the reconsideration process described by the plan or by Social Security. Keep employer letters. Do not ignore the bill while you wait.
Joining a different Advantage or Part D plan does not erase a Part D late enrollment penalty. Medicare.gov says the monthly penalty continues after you switch plans. Part B penalties likewise continue while you have Part B.
If you are helping a parent, check whether they had employer coverage after 65 that nobody documented. Paperwork from a former employer can still matter. David Huff can help you organize the coverage history; he cannot remove a federal penalty.
Does living abroad or having VA coverage change this?
Some situations have special rules. Medicare.gov describes exceptions and creditable coverage in more detail than this article. If you had VA, TRICARE, or coverage based on current employment, bring those documents to Social Security rather than assuming a penalty applies or does not apply.
This page does not invent extra categories. If your facts are uncommon, use the Medicare.gov penalty page and Social Security. A licensed Florida health agent can help you assemble the coverage history.
Lakeland retirees who delayed Part B because a retiree plan felt complete are a common local example of why current-employment status has to be documented, not assumed.
What to do next
If you have not enrolled and still have current-employer coverage, confirm the Special Enrollment Period before you wait. If you already have a penalty on your premium, Medicare.gov and Social Security explain how it was calculated. David Huff, a licensed Florida health agent, can review timing and plan options. He cannot remove a federal penalty. Call (863) 640-3102 or use Get Help.
Review enrollment timing before a penalty period accrues
Bring any employer creditable-coverage letters and your 65th birthday month. An agent review does not enroll you or change a Social Security penalty.
Request a Plan Review Call (863) 640-3102We do not offer every plan available in your area. Currently we represent 10 organizations which offer 73 products in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.
Sources
Penalty formulas are set by Medicare. Dollar premiums change by year and are not listed here. Confirm current figures on Medicare.gov. This page is not connected with or endorsed by the U.S. government or the federal Medicare program.
We do not offer every plan available in your area. Currently we represent 10 organizations which offer 73 products in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.
Company inventory note: The 10 organizations and 73 products referenced above reflect the plans available for the 2026 plan year in the Lakeland/Polk County service area as of August 17, 2026. They are not CMS counts or statewide Florida totals. Counts and available products vary by ZIP code, service area, plan year, and current company authorization. Confirm the ZIP code and current approved platform inventory before relying on these figures. Plan availability, benefits, networks, formularies, pharmacies, and costs are subject to the applicable plan documents and service area.