If You Delay Social Security to 70, Medicare Bills You $609 Every Quarter by Mail. Miss Three and Part B Ends

You turned 65, signed up for Medicare and left your Social Security claim alone so the benefit could keep growing until 70. Then an envelope from Medicare arrives asking for $609. Nobody warned you it was coming, and it looks enough like regular mail to end up in a pile on the counter.

That envelope deserves more attention than anything else Medicare sends you this year, as most retirees never see a Part B premium because Social Security takes it out before the deposit arrives. If you enroll in Medicare and wait to claim Social Security, that automatic deduction never starts, so paying the premium falls to you. Retirees who already collect Social Security or Railroad Retirement benefits have the premium taken from the check, while workers who stayed on an employer plan and put off Part B get no bill yet. The person most at risk is anyone between 65 and 70 holding a CMS-500. All figures below use 2026 Medicare rules.

Why a $609 Bill Lands Every Three Months

Form CMS-500 is the bill Medicare sends to people who pay their premiums directly instead of having them taken from a benefit check. Medicare notes that most people never get one because their premiums come out of Social Security automatically. When nothing can be withheld, Medicare bills Part B every quarter.

The 2026 standard Part B premium is $202.90 a month. Three months of that comes to $608.70, which appears on the notice as $609. Four of those bills add up to $2,436 over a year.

Each bill pays for coverage in advance and lists the months it covers. Your first bill can also include past months, as can any bill that follows a missed payment or a premium change. So the first envelope may ask for more than $609. If your income triggers IRMAA, that surcharge is added to the bill too.

How One Missed Envelope Becomes Lost Coverage

When a payment is late, the unpaid amount carries forward onto your next bill. If that balance remains unpaid, you get a bill marked “Delinquent Bill”. Medicare’s own warning is plain. if you don’t pay the full amount on a delinquent bill by the due date, you could lose your Medicare coverage. A termination notice follows, and Part B ends.

The quarterly schedule is what makes this risky. Four bills a year means four chances to pay, and a single missed envelope already covers three months of premium, so if you travel, move or sort mail in a rush, a full cycle can go by before you notice. By then, the delinquent notice may cover six months of premiums.

Three Fixes Worth Setting Up This Week

Medicare Easy Pay. This free service takes your premium from a checking or savings account each month and adjusts the amount automatically when the premium changes. That turns the quarterly lump into a monthly charge of $202.90. You can sign up under “My Premiums” in your secure Medicare account or by mailing form SF-5510. Deductions can take weeks to begin, and you have to pay by another method until they do. Keep paying the paper bills until your bank statement shows a charge from “CMS Medicare Premiums.”

Bank bill pay. Many banks offer online bill payment from checking or savings. Unlike Easy Pay, a recurring bank payment remains at the amount you entered, so you have to change it yourself every January when the premium resets.

Social Security at 70. When your benefit starts, Social Security begins taking the Part B premium from it and the paper bills stop. The transition is not always clean. A last CMS-500 can still show up for months before the deductions begin. Pay it, and make sure your first benefit statement shows the premium being withheld before you cancel any bank payment.

Lapse Costs Outlast the Missed Bill

Once Part B is ended, Medicare stops paying for doctor visits, outpatient care and lab work. Getting back in usually means waiting for the General Enrollment Period at the start of a year, and coverage does not resume right away. Medicare can restore you if you show good cause, such as a serious illness, and pay what you owe, but approval is up to Medicare.

Over time, a gap without Part B can trigger the late enrollment penalty. It is added to your premium permanently and grows with each full 12 months you go uncovered. A Medigap policy also requires Part B, so a lapse puts that supplement at risk too, and buying a new one later can mean medical underwriting.

Waiting until 70 to claim Social Security locks in a larger check for life, and a mailing should not undo that. Before the next quarterly bill arrives:

1. Log in to your Medicare account today and sign up for Easy Pay. Pay the next CMS-500 by hand while the enrollment processes.
2. Add a calendar reminder for each quarter. If an expected bill hasn’t arrived, call 1-800-MEDICARE rather than waiting for a delinquent notice.
3. When you file for Social Security at 70, check that Part B shows up as a deduction on your first payment, then shut off any bank payment so you don’t pay twice.

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