Do You Need Medicare If You're Still Working at 65?
No, you don't necessarily need to enroll in Medicare at 65 if you're still working.
If you have qualifying health insurance through your employer or your spouse's current employer, you may be able to delay Medicare Part B without a penalty.
The biggest factor is employer size. Companies with 20 or more employees generally have different Medicare enrollment rules than smaller employers.
Before delaying Medicare, you should also consider your prescription drug coverage, whether you contribute to an HSA, and when you plan to retire.
Quick Answer
20 or more employees: Your employer plan generally pays first. You can usually delay Part B (and Part D) without a penalty while you're covered through current employment.
Fewer than 20 employees: Medicare generally pays first. Most people should sign up for Parts A and B at 65, or their employer plan may leave large bills unpaid.
When the job or coverage ends: You get an 8-month window to sign up for Part B. COBRA and retiree coverage don't extend it.
In This Article
Does Your Employer's Size Affect When You Need Medicare?
Yes. Employer size decides whether Medicare or your job-based plan pays first.
That "who pays first" order is what makes delaying Medicare safe in one situation and risky in the other.
| Employer size | Who pays first | What most people do at 65 |
|---|---|---|
| 20 or more employees | Employer plan | Keep employer coverage. Often take premium-free Part A, delay Part B. |
| Fewer than 20 employees | Medicare | Enroll in Parts A and B. The employer plan, if kept, pays second. |
| Spouse's current employer | Same rule, based on the spouse's employer size | Follow the 20-employee test for the spouse's company. |
| Retiree plan or COBRA | Medicare | Enroll in Parts A and B. This coverage is not based on current employment. |
The table comes down to one question: is your coverage tied to someone actively working at a company with 20 or more employees?
If yes, delaying Part B is usually allowed. If no, Medicare is generally meant to be your main coverage starting at 65.
Medicare.gov's guidance on when to sign up walks through the same scenarios.
Working at a 150-employee company
Linda turns 65 and is covered by her employer's group plan. Her plan pays first.
She takes premium-free Part A, skips Part B for now, and signs up for Part B when she retires.
Working at a 12-employee company
Tom turns 65 at a small firm. Medicare is expected to pay first, and his employer plan pays second.
If he skips Part B, his plan may only pay what it would have paid as secondary, leaving him with most of the bill.
Exception worth checking: Some small employers belong to a multi-employer or multiple-employer plan.
If at least one participating employer has 20 or more employees, the group plan may still pay first for everyone in it, unless the small employer requested an exception.
Ask your benefits administrator, in writing, whether your plan pays primary or secondary to Medicare.
What We Recommend Checking Before Delaying Medicare
Being allowed to delay Part B doesn't automatically mean you should.
When we talk with people working past 65, the real question is often whether their employer coverage is worth keeping. We recommend comparing the full cost of coverage, not just the monthly premium.
Which Parts of Medicare Can You Delay While Working?
Each part of Medicare has its own rules, so it helps to look at them separately.
| Coverage | Can you delay it? | What to know |
|---|---|---|
| Part A | Yes, but many don't | Premium-free for most people. Taking it at 65 is usually fine unless you contribute to an HSA. |
| Part B | Yes, with 20+ employee coverage | Has a monthly premium. Delaying avoids paying for coverage you may not need yet. |
| Part D | Yes, if your drug coverage is creditable | Your employer sends an annual notice saying whether its drug coverage is creditable. |
| Medigap | Yes, and usually should wait | Your 6-month Medigap open enrollment starts the first month you're both 65 or older and enrolled in Part B. |
For most people at a large employer, the practical setup is Part A now, Part B and Part D later.
The one big exception is anyone contributing to a health savings account, covered below.
Waiting on Part B also preserves your Medigap open enrollment period.
That 6-month window lets you buy any Medigap plan without health questions. It begins the first month you're 65 or older and enrolled in Part B, so someone who first takes Part B at 68 generally still gets it then.
Is Medicare or Employer Health Insurance More Affordable?
It depends on what you pay for each, not just which one you're allowed to keep.
A fair comparison looks at total yearly cost on both sides.
| Cost to compare | Employer plan | Original Medicare + Medigap + Part D |
|---|---|---|
| Monthly premiums | Your share of the group premium | Part B + Medigap + Part D premiums |
| Deductibles | Plan deductible (often high on HSA plans) | Part B deductible (Plan G); little else |
| Out-of-pocket exposure | Plan's out-of-pocket maximum | Usually very low with Medigap Plan G |
| Doctor access | Plan network | Any provider that accepts Medicare |
| Family coverage | May cover a spouse or dependents | Covers only you |
Employer coverage may be the better fit when your share of the premium is small or the plan also covers a spouse who isn't on Medicare yet.
Medicare may be more affordable when you're paying a large premium for employer coverage with a high deductible.
Compare the total annual costs before deciding, since your age, location, employer contribution, and health needs all change the answer.
For a deeper look at how the two plans work together if you keep both, see how Medicare works with employer health insurance.
Higher earners, take note: Part B and Part D premiums rise with income, through a surcharge called IRMAA.
It's based on your tax return from two years earlier. If you're still drawing a full salary, delaying Part B can avoid paying the higher bracket while you don't need the coverage.
What Happens to Your HSA If You Enroll in Medicare?
You can keep and spend the money in your HSA after enrolling in Medicare.
What you can't do is contribute to it, including employer contributions, for any month you have Medicare coverage.
That includes Part A, even though it's premium-free.
The 6-month look-back
The look-back generally applies when you sign up for premium-free Part A more than six months after turning 65.
In that case, Part A coverage is usually backdated up to six months before the month you apply. It never starts earlier than the month you turned 65.
If you enroll at 65, during your initial window, the look-back generally doesn't come into play.
HSA contributions made during those backdated months become excess contributions, which can be taxed and penalized under IRS HSA rules.
This is where people get tripped up: the date your Medicare starts and the date your HSA contributions must stop are two different dates.
- End of DecemberMaria, age 67, makes her last HSA contribution and tells HR to stop employer deposits.
- January – JuneNo contributions. She stays on her employer plan.
- JulyShe retires and applies for Medicare in July, asking Part B to start August 1.
- ResultIf Maria's premium-free Part A coverage is backdated six months, it could begin January 1. Because she stopped contributing in December, she would avoid excess contributions from the retroactive coverage period.
If you're enrolling after 65 and 6 months, a practical guideline is to stop all HSA contributions at least six months before you apply for Medicare.
Many people build in an extra month of cushion so a payroll deposit doesn't slip through.
Employer HSA deposits are the contribution people forget about. Stopping your own payroll deduction doesn't stop the company's deposit, so ask HR to confirm in writing that both have ended.
Social Security triggers this too. If you start Social Security retirement benefits at 65 or later, you're automatically enrolled in Part A.
You generally can't turn down Part A without repaying the Social Security benefits you've received.
If you're already collecting Social Security, you most likely already have Part A and can't contribute to an HSA.
When Should You Sign Up If You Plan to Retire?
Ideally, before your employer coverage ends, so there's no gap.
If you qualify, once you stop working or lose that coverage, you have a Special Enrollment Period to sign up for Part B without a late penalty.
You don't have to retire to switch from employer coverage to Medicare. If you're still working and have qualifying employer group coverage, you can generally enroll in Part B during your Special Enrollment Period, even before your employment ends.
The 8-month Part B window
The window lasts eight months, according to Social Security's Part B enrollment guide.
The clock generally starts the month after your employment ends or your group coverage ends, whichever happens first.
So if you retire in May but your coverage runs through June, the clock starts in June, not July.
COBRA does not extend this deadline. COBRA isn't coverage based on current employment, so the 8-month clock runs while you're on it.
Retiree health coverage works the same way. If you wait for COBRA to run out before signing up, you can miss the window entirely.
Part D has two separate rules
These get mixed together often, but they are different rules with different jobs.
| Rule | What it does | Timeframe |
|---|---|---|
| Part D Special Enrollment Period | Lets you join a Part D plan after losing employer drug coverage | Generally two full months after the month that coverage ends |
| 63-day creditable coverage rule | Decides whether you owe a Part D late penalty | Going 63 or more days in a row without creditable drug coverage, after your initial enrollment period, can trigger the penalty |
Use the enrollment period to join a plan on time, and keep any gap in creditable coverage shorter than 63 days to avoid the Part D late enrollment penalty.
Signing up so your Part D starts the day after employer coverage ends handles both.
How to apply
- Complete form CMS-40B (the Part B application) and form CMS-L564 (Request for Employment Information).
- Your employer fills out the CMS-L564 to confirm your group coverage dates. Get it from HR before you leave.
- You can submit both online through Social Security, by fax, or by mail.
- In the remarks section, write the month you want Part B to begin, so it lines up with your last day of employer coverage.
- Once Part B is set, compare Medigap plans and a Part D plan so all three start together.
For the full process, see our step-by-step guide to signing up for Medicare.
What Happens If You Delay Medicare When You Shouldn't?
Delaying without qualifying coverage can cost you in two ways: late enrollment penalties and gaps in coverage.
| Coverage | Late enrollment penalty | How long it lasts |
|---|---|---|
| Part B | 10% added to the premium for each full 12-month period you could have had Part B but didn't | Generally for as long as you have Part B |
| Part D | 1% of the national base premium for each month without Part D or creditable coverage | Generally for as long as you have Part D |
| Part A | Only applies if you have to buy Part A (most people don't) | Limited period |
The penalty isn't the only problem.
If you miss your Special Enrollment Period, you may have to wait for the General Enrollment Period, January 1 through March 31, with coverage starting the month after you sign up.
That can leave you without full coverage for months.
Our guide to Medicare enrollment periods walks through each window.
Delaying Part B doesn't by itself cost you your Medigap open enrollment period. When you first enroll in Part B at 65 or older, that 6-month window generally starts then.
Our guide to Medigap guaranteed-issue rights covers other situations where you're protected.
How Do You Know Whether You Should Enroll Now?
Use this as a quick self-check.
| If this describes you… | Then… |
|---|---|
| Employer has fewer than 20 employees | Enroll in Parts A and B at 65, unless your plan confirms in writing it pays first. |
| Covered by retiree insurance or COBRA | Enroll in Parts A and B now. |
| Large employer, contributing to an HSA | Delay Parts A and B, and delay Social Security. Stop HSA contributions in time. |
| Large employer, no HSA | Consider premium-free Part A now, and compare total costs before delaying Part B. |
| Retiring within the next few months | Request the CMS-L564 from HR now and line up Part B, Medigap, and Part D to start together. |
Frequently Asked Questions
Do I have to sign up for Medicare at 65 if I'm still working?
Not always.
If you have group coverage through your own or your spouse's current employer with 20 or more employees, you can generally delay Part B without a penalty.
Should I sign up for Part A even if I keep my employer plan?
Many people do, since it's premium-free for most and can help with hospital costs.
The main reason not to is if you or your employer contribute to an HSA.
Does my spouse's employer coverage count?
Yes, if it's based on your spouse's current employment.
The same 20-employee rule applies, based on the size of your spouse's employer.
Is COBRA considered creditable coverage for Part B?
No. COBRA doesn't let you delay Part B without a penalty, and it doesn't pause your 8-month Special Enrollment Period.
COBRA drug coverage can count as creditable for Part D, so check the notice from your plan.
Can I contribute to my HSA after I turn 65?
Yes, as long as you aren't enrolled in any part of Medicare and aren't collecting Social Security.
If you'll enroll more than six months after turning 65, plan to stop contributions at least six months before you apply for Medicare.
What if my employer has fewer than 20 employees and I skipped Part B?
Your employer plan may have paid as if Medicare had already paid its share, which can leave you with unpaid bills.
Call Social Security to ask about your enrollment options, and contact your plan about claims since you turned 65.
The Bottom Line
If you work for a company with 20 or more employees, you can usually keep your employer plan and delay Part B, but compare the full cost before assuming that's the better deal.
At a smaller employer, sign up for Parts A and B at 65.
Either way, time your HSA contributions around the six-month look-back, and sign up for Part B within eight months of losing employer coverage, not when COBRA runs out.
