Your Social Security Check Could Shrink When You Turn 65 - Here's Why

If you claim Social Security before age 65, you may be used to a certain amount hitting your checking account each month. So, when that amount drops once you turn 65, it may be an unwanted surprise.

This may feel like a benefit cut, but it's actually an automatic deduction for Medicare premiums. Learn what's actually being taken from your check, how this affects your retirement goals, and what you can do to avoid it.

Why your Social Security can shrink at 65

While you can claim Social Security benefits as early as 62, you generally don't become eligible for Medicare until age 65. That means your Social Security checks before 65 aren't reduced by Medicare Part B premiums.

Most people enroll in Part B of Medicare, the portion that covers doctor and outpatient visits, at age 65. If you're already receiving Social Security, the government takes this premium amount out of your benefit payment before depositing it into your bank account.

What this looks like in practice

Imagine you have a Social Security benefit of $2,071. Your standard Part B premium is $202.90 for 2026 (the amount can change over time and may vary based on your situation). The government would take that premium from your benefit deposit, leaving you with just $1,868.10 each month.

While it looks like your benefit has been reduced, it hasn't. Your take-home amount has just changed due to what you owe in premiums.

What determines deposit amounts

It's important to distinguish between your official Social Security benefit and the amount that actually lands in your bank account each month.

Your benefit is calculated using your earnings history and claiming age. That figure doesn't change just because you turn 65. However, your take-home pay can change based on Medicare premiums and any income‑related surcharges that are withheld. Knowing this difference can help alert you to errors and plan your retirement budget more accurately.

Why enrollment is automatic

If you've been receiving Social Security benefits for at least four months before you turn 65, you're typically enrolled automatically in Medicare Part A and Part B. You won't need to apply separately, and you'll get a Medicare card in the mail.

Part A is free for most people who have paid into the program through working in previous years. Part B isn't, and you'll be automatically enrolled unless you opt out. 

The system assumes most retirees want coverage and simplifies the process by deciding for you (unless you say otherwise). But that first automatic deduction can still surprise people when it shows up on their benefit statement.

Who can safely opt out of Part B (and the deduction)

Some people can delay Part B without penalties, but you should understand the rules and your specific situation before you try it. Specific groups of people this may apply to include:

• People still working at 65 and covered by a select employer plan
• Spouses covered under a select employer plan

What do we mean by a 'select' employer plan? In general, the workplace plan must cover at least 20 employees for it to be treated as your primary coverage instead of Medicare.

Who should not opt out

As mentioned above, if you don't have workplace insurance or your employer plan is too small to qualify, you won't want to put off Medicare Part B. Otherwise, you'll be hit with a 10% Part B premium penalty for each full 12‑month period you were eligible but didn't sign up, and that surcharge can last as long as you have Part B.

You'll also be uninsured during any gap between losing employer coverage and the date your Medicare plan begins. This gap leaves you open to costly health risks, and could push your Medicare premiums upward when you finally do get a plan.

How to opt out of Medicare Part B

If you've decided you can safely avoid Part B for now, here's how:

1. If you'll be automatically enrolled, you'll get a card and welcome packet in the mail. Use the instructions included, usually returning a card or form, to express your interest in declining coverage.
2. You may also contact Social Security directly online, via phone, or at a local office before you get the packet.

Timing matters, as you'll want to do this before coverage begins to avoid unwanted deductions. Document everything, including when you sent communication, in case you need to refer to it later. Confirm with SSA that your request was received and processed.

Bottom line

Social Security benefit amounts typically don't change at 65, but Medicare Part B premiums can reduce the net deposit you see in your bank account. And that can flip your retirement plan upside down.

Higher-income retirees may pay even more than the standard Part B premium due to Income-Related Monthly Adjustment Amounts (IRMAA), which can further reduce what's deposited each month. To avoid any costly surprises, do the math on premiums and decide if continuing with an employer plan may be a better option before you retire.