The Automatic Deduction That Catches Many Social Security Recipients Off Guard at 65

Many people who claim Social Security before 65 get used to seeing the same amount arrive in their bank account each month. After a while, it simply becomes part of the household budget.

Then Medicare starts, and the deposit suddenly looks a little different. For most retirees, the change comes from Medicare Part B premiums being deducted directly from their Social Security benefit.

Understanding what's happening, and what choices you have around it, is one of the simpler ways to avoid money mistakes in the first months of Medicare eligibility.

What's actually being deducted from your Social Security

For people who are already collecting Social Security at least 4 months before turning 65, Medicare enrollment is usually automatic. A Medicare card typically arrives a few months before coverage begins, and Part B coverage starts unless you choose to decline it.

While Medicare Part A is premium-free for most people, Part B comes with a monthly premium because it covers services such as doctor visits, outpatient care, and preventive care. Rather than sending a separate bill, Medicare usually deducts that premium directly from your Social Security benefit.

In 2026, the standard Part B premium is $202.90 a month, which is the amount many beneficiaries first notice missing from their deposit.

Higher-income beneficiaries pay more under IRMAA (the income-related monthly adjustment amount), which kicks in at modified adjusted gross income above $109,000 for individuals or $218,000 for couples.

The one situation where declining Part B can make sense

The Part B deduction is automatic for most people, but that does not mean everyone has to take Part B at 65. If you or your spouse still works and receives health coverage through a current employer, you may be able to delay Part B without facing a late-enrollment penalty.

In that situation, you can usually sign up later through a Special Enrollment Period while the coverage remains in place or during the eight months after the job or coverage ends.

The rules can be different when the employer has fewer than 20 employees. In those cases, delaying Part B may lead to penalties or gaps in coverage, even if you are still covered by an employer health plan.

Before declining coverage, check with your benefits department to confirm how the rules apply to your situation.

Coverage types that don't qualify for delaying Part B

While health coverage from a current employer may allow you to delay Part B without a penalty, the rules are different for COBRA and retiree health plans.

COBRA lets you keep your employer health insurance after leaving a job, but Medicare does not treat it as active employer coverage. If you decline Part B because you have COBRA, you may not qualify for a Special Enrollment Period later and could face a late-enrollment penalty.

Retiree health plans work much the same way. Medicare doesn't treat them as active employer coverage either, so declining Part B based on retiree coverage can also trigger a late-enrollment penalty.

The cost of declining Part B without qualifying coverage

Declining Part B without qualifying employer coverage can lead to a permanent premium increase. Medicare generally adds 10% to your premium for every full 12-month period you were eligible for Part B but did not enroll.

For example, someone who waits two years to enroll without qualifying for a Special Enrollment Period would face a 20% penalty.

Based on the standard 2026 Part B premium of $202.90, that would add $40.58 a month to the bill, bringing the total to $243.48 a month for as long as the person carries Part B.

Missing your enrollment window can also leave you without Part B coverage for a period of time if you have to wait for Medicare's General Enrollment Period to sign up. During that gap, you may be responsible for the full cost of doctor visits, outpatient care, preventive services, and other medical expenses that Part B would normally help cover.

How to decline Part B if you qualify

If you have confirmed that your health coverage qualifies you to delay Part B, the easiest approach is to decline it before the coverage start date listed on your Medicare card. Keeping the card and taking no action is generally treated as accepting Part B, which means the premium deduction will begin automatically.

If Part B is already active and you want to drop it, Social Security generally requires Form CMS-1763, and you may be asked to complete an interview before coverage can be canceled.

When your job-based coverage eventually ends, you can enroll in Part B through a Special Enrollment Period. Social Security typically requires:

• Form CMS-40B to enroll in Part B.
• Form CMS-L564 to verify employment or job-based coverage.

Enrolling within eight months of losing that coverage allows Medicare to begin the month after your paperwork is received.

Bottom line

Many retirement decisions leave room to change course later, but Medicare enrollment is one where timing can have lasting consequences.

Before your 65th birthday comes and goes, take a close look at how Medicare and Social Security fit together. Understanding that connection can help you protect your senior benefits and move into the next stage of retirement with a little more confidence.