Turning 65 in New York: The Seven-Month Window and the Penalty That Never Goes Away

Medicare enrollment runs seven months around your 65th birthday. Skipping Part B safely depends on employer size; a mistake costs 10% more per year, for life.

Nathan Brody · Published September 14, 2026

The short version

Your initial enrollment period is seven months: the three months before your birthday month, the birthday month itself, and the three months after.
The Part B late penalty is 10% of the premium for every full 12 months you delayed, and you pay it for as long as you have Medicare. It does not expire.
You can delay Part B without penalty only while covered by a current employer’s plan — yours or a spouse’s — at an employer with 20 or more employees.
Below 20 employees, the rule flips: Medicare becomes the primary payer, and skipping Part B leaves a hole rather than saving money. In a city of small employers this is the trap.
When the job or the coverage ends, an 8-month special enrollment period opens with no penalty. It runs from the end of employment or coverage, whichever comes first.

The window

Seven months, centered on your birthday month: three before, the month itself, three after.

Signing up in the three months before is the version that works, because coverage can start the month you turn 65 with nothing in between. Signing up after the birthday pushes the start date later, and a gap in the middle is a month where you are paying for care yourself.

If you already receive Social Security benefits, enrollment in Part A and Part B is generally automatic and the card arrives without you asking. If you do not, nothing happens by itself — and that is the group that misses the window.

The one question that decides whether you can wait

How many people does the employer have?

You may delay Part B without a penalty if you are covered by the health plan of a current employer — your own or your spouse’s — and that employer has 20 or more employees.

At 20 or more: the employer plan pays first, Medicare second. Delaying Part B is a legitimate choice and costs nothing later, because an 8-month special enrollment period opens when the employment or the coverage ends.

Below 20: Medicare becomes the primary payer once you are eligible. The employer plan pays second — and it pays as if you had Part B whether or not you actually enrolled. Skipping Part B here does not save money; it creates a gap that shows up as denied claims.

Retiree coverage and COBRA are not current employer coverage. Neither protects you from the penalty. This is one of the most expensive misunderstandings in the whole subject.

The question to ask, in one sentence to HR: “Does this employer have 20 or more employees for Medicare coordination purposes, and does our plan pay primary or secondary once I turn 65?”

Get the answer in writing if you can. It is the document that justifies the delay if the penalty is ever assessed in error.

What the penalty actually is

10% of the standard Part B premium for each full 12-month period you could have had Part B and did not, added to your premium permanently.

Seven years late is not a one-time charge of seven years’ premiums. It is 70% more, every month, for the rest of your life. That is the shape of it, and it is why the arithmetic of “I’ll deal with it later” never works.

Part D has its own late penalty on a different formula, which is why people who delay drug coverage because they take no medication get a surprise later.

The order that works

Three months before the birthday month, find out about the employer plan. Twenty employees or more, and who pays primary. This single answer determines everything after it.
If there is no current employer coverage, enroll in Part A and Part B in the three months before your birthday month so coverage starts on time.
If you are delaying Part B, get the coverage confirmed in writing and diarize the date employment ends. The 8-month clock starts there, not when you feel ready.
Check the Medicare Savings Programs before paying a premium. New York’s thresholds are higher than most states’: QMB at 138% of the federal poverty level, QI at 186%. The state pays the Part B premium at those levels, which for most people arrives as a larger Social Security payment. Medicare Savings Programs in New York.
Only then choose between Original Medicare and Advantage. It is a real decision with real trade-offs, and it is a separate one. Advantage or Original.

If you are still working and the coverage is good

Nothing forces you to take Part B at 65 in that case, and at an employer with 20 or more people, nothing punishes you for waiting.

Part A is a different question. For most people it has no premium, and enrolling costs nothing — with one exception worth naming: contributions to a health savings account must stop once you have any part of Medicare. If you are funding an HSA, that changes the timing, and it is worth working out before the birthday rather than after.

When the job ends

The 8-month special enrollment period starts at the end of employment or of the employer coverage, whichever comes first. Enrolling inside it carries no penalty.

Two things go wrong here. People count from the end of COBRA rather than the end of the job — COBRA does not extend the window. And people wait until month seven, then discover Part B coverage does not start instantly. Start it in the first month.

Free, unbiased help with any of this in New York — the state’s health insurance assistance program counsels without selling anything.

Questions people ask

Seven months around your 65th birthday: the three months before your birthday month, that month, and the three months after. Enrolling before the birthday month avoids a gap.

Can I skip Part B if I am still working?

Only if you are covered by a current employer’s plan — yours or a spouse’s — and the employer has 20 or more employees. Retiree coverage and COBRA do not count.

What happens if my employer has fewer than 20 employees?

Medicare becomes the primary payer and the employer plan pays second. Not enrolling in Part B leaves claims unpaid rather than saving you a premium.

How bad is the Part B late penalty?

It is 10% of the premium for each full 12 months of delay, added permanently. Seven years late means paying 70% more every month for life.

How long do I have after I stop working?

Eight months, counted from the end of employment or of the employer coverage, whichever comes first. COBRA does not extend it.

Can New York help with the premium?

Yes. The Medicare Savings Programs pay the Part B premium at 186% of the federal poverty level and both premiums and cost sharing at 138%, which are higher thresholds than most states use.

Sources

Medicare.gov — working past 65 (checked 2026-09-14)
Medicare.gov — avoid late enrollment penalties (checked 2026-09-14)
Social Security Administration — when to sign up for Medicare (checked 2026-09-14)

More in Life Changes and Health Coverage in New York: Every Clock That Starts

Your Job Ended: COBRA or the Marketplace — COBRA keeps your doctors and costs what your employer was quietly paying. In New York the alternatives are strong, and both 60-day clocks run at once.
Your Hours Were Cut: Losing Coverage Without Losing the Job — Hours cut below the plan's eligibility line? That is a qualifying event: the same 60-day clock and COBRA rights as a layoff, and the Essential Plan may be free.
Starting a New Job: The 90-Day Rule and the Gap It Leaves — No group plan may make you wait more than 90 calendar days; 'the first of the month after 90 days' is lawful only inside that cap. How to cover the gap.

This page explains how the system works. It is not medical advice. More.