How the Part B Penalty Works
For each full 12-month period you could have had Part B but didn't sign up — and didn't have qualifying coverage — 10% is added to your monthly premium. Unlike some penalties, this one is not temporary: it applies for as long as you have Part B.
Who Does NOT Owe a Penalty
Delaying Part B is penalty-free when you have coverage through current employment — yours or your spouse's — from an employer group health plan. When that employment or coverage ends, a Special Enrollment Period lets you sign up for Part B without penalty. Two traps inside that rule: COBRA does not count as current employer coverage, and retiree coverage doesn't either. Many lifetime penalties trace back to exactly those two misunderstandings.
What to Do If You're Approaching 65 and Still Working
Confirm — in writing, from the benefits administrator — whether your employer coverage lets you safely delay Part B. It's a five-minute question that can prevent a lifetime surcharge.