Working past 65: take Medicare or delay?

The 20-employee rule

"Active" matters. Retiree health benefits, severance health benefits, and COBRA are not active group coverage for this rule. They don't trigger or extend a Special Enrollment Period.

Part A almost always makes sense

For most people, Part A is premium-free because they earned 40 quarters of Medicare taxes. Taking premium-free Part A while working doesn't cost anything and can pick up some hospital costs that your employer plan leaves to you.

The exception is HSAs. We'll come back to that below.

When delaying Part B usually makes sense

• You're on a true large-employer group plan (20+ employees)
• Your group plan is solid and you don't want to pay the Part B premium twice
• You're confident you can act within 8 months of losing that coverage

When you eventually retire or lose the coverage, you'll use the Part B Special Enrollment Period to sign up without a late penalty.

When taking Part B at 65 usually makes sense

• Small employer (fewer than 20 employees) — Medicare becomes primary anyway
• High-deductible plan where adding Medicare reduces your out-of-pocket exposure
• You're on COBRA or retiree coverage (those do not delay the Part B deadline)
• You have ESRD or qualify for Medicare on disability

HSAs and Medicare don't mix

Two things to know:

• Retroactive Part A. If you delay enrolling in Social Security past age 65 and later sign up, Part A is backdated up to 6 months (but not earlier than your 65th birthday). Stop HSA contributions 6 months before you plan to enroll to avoid an excise tax on excess contributions.
• Social Security forces Part A. If you take Social Security benefits, you can't decline premium-free Part A. So Social Security and HSA contributions are also incompatible once you turn 65.

The 8-month Special Enrollment Period

When your active employment or your group health coverage ends (whichever comes first), you have 8 months to enroll in Part B without a late penalty. Coverage starts the month after you sign up. Don't wait until month 7. Networks and provider appointments take time, and the gap between losing coverage and Part B starting can leave you exposed.

You also get a 63-day Part D Special Enrollment Period when you lose creditable drug coverage. Confirm in writing that your employer drug coverage is creditable — if it isn't, you may owe a Part D late penalty.

What to do before your birthday

1. Confirm your employer's size in writing (20+ or fewer)
2. Get a creditable coverage letter for both medical and drug coverage
3. If you have an HSA, decide your contribution strategy now
4. Decide whether to take premium-free Part A
5. Set a calendar reminder for the day your active coverage ends

See the full turning-65 checklist

Frequently asked questions

Do I have to take Medicare at 65 if I'm still working?

Not always. If you have creditable employer coverage from an employer with 20 or more employees, you can usually delay Part B and Part D without a late penalty. Most people still enroll in premium-free Part A because it can complement employer coverage at no extra cost.

What is a Special Enrollment Period for Part B?

When your active employer coverage ends, you get an 8-month Special Enrollment Period to sign up for Part B without a late penalty. Coverage starts the month after you enroll. COBRA and retiree coverage do not extend this window, which is the most common mistake we see.

Should I enroll in Part A while still working?

Usually yes, because Part A is premium-free for most people. The exception is if you're contributing to a Health Savings Account (HSA). Enrolling in any part of Medicare (including premium-free Part A) ends HSA contribution eligibility, including employer contributions.

Does my spouse's job count as creditable coverage?

Yes, if your spouse is actively working for an employer with 20 or more employees and you're covered on their group plan. The Special Enrollment Period rules apply the same way when their employment ends, not when they retire from active work.

What if my employer has fewer than 20 employees?

Small-employer plans become secondary to Medicare at 65. You need to enroll in Parts A and B during your Initial Enrollment Period or risk being effectively uninsured. Confirm in writing whether your plan is primary or secondary before delaying.