Skipping Medicare Part B when first eligible does not just delay a decision. For most people who wait too long, it sets a permanent price. Medicare’s rule is a flat 10% added to the Part B premium for every full year someone could have enrolled and didn’t, and that add-on typically sticks around for as long as the person keeps Part B. For someone who waits several years, the difference compounds into a real, recurring monthly cost.
The 10% Rule, Counted In Full Years
Medicare adds an extra 10% to the Part B premium “for each year you could have signed up for Part B, but didn’t,” according to Medicare’s official guidance on avoiding late enrollment penalties. The penalty stacks: someone who waits two full years past their enrollment window pays roughly 20% more than the standard premium, and someone who waits three pays roughly 30% more, calculated directly from that 10%-per-year rule. Against the 2026 standard Part B premium of $202.90 a month, a two-year delay works out to an extra $40.58 a month, a figure this article derives from Medicare’s stated rate and the current premium, not a number Medicare itself publishes as a dollar amount.
The clock that determines whether someone “could have signed up” starts with a specific 7-month window. The Initial Enrollment Period “begins 3 months before the month a person turns 65, their birthday month and ends 3 months after the person turns 65,” according to the Centers for Medicare & Medicaid Services. Anyone who lets that 7-month window close without a qualifying exception has begun accumulating the 10%-per-year penalty from that point forward, whether or not they realized the window had a deadline.
Inside the kit: The 51 state Medicare cost-help packs and the section covering Extra Help and the programs that pay part of the Part B premium give someone carrying a permanent surcharge a place to check whether assistance lowering that premium exists. Open The Medicare Cost & Coverage Protection Kit.
Why It Usually Never Goes Away
Unlike a one-time fee, the Part B penalty is “usually charged for as long as you have that type of coverage,” which Medicare’s own guidance describes as, for most people, a lifetime penalty, per the same Medicare avoid-penalties page. Because most people keep Part B for the rest of their lives once enrolled, the surcharge from a delay early in retirement can end up costing far more over time than the premium a person was trying to avoid by waiting in the first place.
The Base The Penalty Is Computed On For 2026
The 10% figure is a percentage, not a flat fee, and what it’s a percentage of matters. Medicare’s standard Part B premium for 2026 is $202.90 a month, according to the agency’s Medicare costs page, and Medicare calculates the late-enrollment penalty as a share of that standard premium, then adds the result on top of whatever premium a person actually owes: the standard amount, or a higher income-adjusted amount for beneficiaries who pay an income-related monthly adjustment. That means two people with very different total Part B bills can carry the exact same dollar penalty for the exact same number of years missed, because the penalty itself is pegged to the standard premium rather than to what either person individually pays.
The Special Enrollment Period That Avoids The Penalty Entirely
The penalty is not automatic for everyone who enrolls in Part B after 65. People with health coverage through their own current job or a spouse’s current job can qualify for a Special Enrollment Period, with 8 months to sign up for Part B, counted “after the group health plan coverage or the employment ends, whichever happens first,” without owing any late-enrollment penalty, according to Medicare’s enrollment timing guidance. That exception has a limit worth knowing before relying on it: Medicare’s guidance states plainly that “COBRA isn’t considered group health plan coverage,” so someone who leaves a job and switches to COBRA does not get extra time under this rule. The 8-month clock still starts when the actual employment or employer coverage ends, regardless of any COBRA coverage picked up afterward.
Where To Check For Help With The Part B Premium
Medicare’s guidance states the 10% per-year rate, the lifetime duration and the 8-month Special Enrollment Period, but it stops short of walking any one household through an annual check on what’s actually being paid, or how to document a dispute if the premium billed looks wrong.
The Medicare Cost & Coverage Protection Kit walks through an annual cost review alongside an appeal and call log for tracking correspondence about a premium question.
Review the annual cost check in The Medicare Cost & Coverage Protection Kit.
This article was produced with AI assistance and checked against the primary sources linked above.
David M. Keller is a finance writer based in Columbus, Ohio, covering personal finance and consumer-focused economic topics. He earned his degree in journalism from Ohio University and began his career reporting on local business and economic trends for a regional media outlet. Since then, he has contributed to a variety of online publications, focusing on clear, practical coverage of topics such as cost of living, debt, and everyday financial decision-making.
