The Medicare Part B Bill That Can Catch You Off Guard If You Postpone Social Security

Many retirees never notice their Medicare Part B premium because Social Security usually withholds it before the monthly benefit is deposited. But if you sign up for Medicare at 65 and wait to claim Social Security later, there is no benefit check for Medicare to take the premium from. That can create an unexpected cash-flow issue, even for people who have planned carefully.

That matters even more after Medicare premiums increased. The Centers for Medicare & Medicaid Services (CMS) says the standard Part B premium is $202.90 a month, up from $185 the prior year. For people paying out of pocket, that amount does not disappear inside a smaller Social Security payment; it becomes a separate bill that has to be built into the household budget.

Here is why the surprise happens and how to avoid an expensive mistake.

Why Part B premiums still have to be paid if Social Security is delayed

Medicare enrollment and Social Security claiming are two different decisions, so it is possible to enroll in Part B at 65 and wait until 70 to collect retirement benefits. In most cases, Medicare takes the Part B premium out of Social Security, which reduces the deposit but eliminates the need to remember a separate bill.

If there is no monthly Social Security payment, Medicare sends a quarterly invoice instead. That bill, called the Medicare Premium Bill (CMS-500), usually arrives around the 10th of the month and lists the coverage periods being charged.

The monthly premium turns into a bill of about $609

At the standard 2026 rate, Part B costs $202.90 per month. Three months therefore total $608.70, which means one quarterly bill comes to roughly $609. Over a full year, that works out to about $2,436.

Unlike a smaller monthly charge, the CMS-500 bundles three months of premiums into one payment. Someone who can comfortably handle $202.90 each month may still be short when nearly $609 arrives at the same time as property taxes, insurance, or other regular expenses.

Your first invoice may be larger than expected

Do not assume every bill will equal exactly three times the standard premium, especially at the start. Medicare says the first CMS-500 can include charges for earlier months as well as premiums for upcoming coverage, so it is worth checking the dates before assuming there is a mistake.

Some higher-income retirees may also owe an income-related monthly adjustment amount, or IRMAA, which is based on income rather than on when Social Security is claimed. In 2026, Part B surcharges begin above $109,000 for individual filers or $218,000 for joint filers. The first surcharge tier raises the premium to $284.10 a month, or $852.30 for three months.

Missing a bill can put coverage at risk

This is not a notice to set aside and deal with later. Medicare generally expects payment by the 25th of the month, and any unpaid balance rolls over to the next bill. At the standard 2026 rate, two unpaid quarterly bills would total $1,217.40.

If Medicare issues a notice marked “Delinquent Bill,” failing to pay by the deadline can result in cancellation of coverage. Because one missed quarterly bill covers three months of premiums, ignoring the mail can quickly lead to a balance that is difficult to catch up on.

Ways to simplify payments before Social Security starts

You can pay through your Medicare account, use online bill pay through your bank, or enroll in Medicare Easy Pay, which automatically pulls the premium from a checking or savings account each month.

Easy Pay usually drafts payments on the 20th, but enrollment can take six to eight weeks, so do not overlook any bills due before it begins. Once Social Security starts, perhaps at 70, review the first benefit statement to make sure Part B is actually being withheld instead of assuming Medicare has already changed the payment method. After confirming the withholding is active, cancel any separate recurring bank payment and stop Easy Pay, which can take up to four weeks, while checking for overlapping charges.

The bottom line

Delaying Social Security can fit into a longer-term income plan, but it does not delay the cost of Medicare Part B. Could you handle a payment of about $609 if it landed during the same week as another major expense? Setting aside money each month and automating payments can make the shift easier.

It may also be worth looking into Medicare Savings Programs, which can help eligible people pay Part B premiums depending on income, resources, and state rules. That can matter both while waiting to claim benefits and later when living on Social Security alone, when every predictable expense needs a plan.

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