Guide

Medicare While Still Working: What to Do at 65

If you're working past 65, the Medicare decisions get more complicated. Here's the framework for evaluating employer coverage versus Medicare, including the rules that change based on employer size.

The 60-something professional working past 65 is a common shape today. Your career might be hitting its peak, you might love the work, you might be putting kids through college, or you might just want a few more years of compensation before retirement. Whatever the reason, working past 65 turns the Medicare enrollment decision from a single moment (your 65th birthday) into a multi-step decision tree that depends on your employer’s size, your other coverage, your HSA situation, and your spouse’s coverage.

This guide is the framework for working through that decision tree.

Step 1: Determine your employer’s size

The single most important fact for Medicare timing while working is whether your employer has 20 or more employees.

20+ employees: Federal law (the Medicare Secondary Payer rules) requires the employer plan to be primary for active employees age 65+. Medicare is secondary. You can delay Part B enrollment without penalty as long as you remain on the employer plan based on current employment.

Under 20 employees: Medicare is generally primary. You’re typically expected to enroll in Part B at 65 even with employer coverage. Skipping Part B usually creates coverage gaps and lifetime penalties.

The 20-employee threshold counts all employees of the company, not just those covered by the health plan, and includes part-time employees in the count. If you work for a 50-person law firm, the 20+ rule applies. If you work for a 12-person dental practice, the under-20 rule applies.

For self-employed people and sole proprietors with no employees, Medicare is generally considered primary regardless of insurance arrangements. Plan to enroll in Parts A and B at 65.

Step 2: Evaluate your employer plan against Medicare

If your employer has 20+ employees and you’re considering whether to stay on the employer plan or enroll in Medicare, run a side-by-side comparison.

Employer plan considerations:

Monthly premium contribution (often $200–$600/month for family coverage)
Deductible
Out-of-pocket maximum
Provider network
Prescription drug formulary
Spousal/dependent coverage if applicable

Medicare alternative considerations:

Part B premium ($185/month in 2026, more if IRMAA applies)
Plan G or N premium for Medigap ($100–$200/month)
Part D premium ($20–$50/month)
Part B deductible ($257/year)
Total: roughly $300–$430/month for one person

For an individual without dependents on a company plan with high premiums, Medicare often comes out cheaper. For someone covering a spouse and family on the company plan, the employer coverage is usually substantially cheaper.

The cost-benefit varies by your specific situation. A 67-year-old earning $200,000/year on a company plan paying $400/month for individual coverage has different math than a 67-year-old earning $80,000/year paying $80/month for individual coverage.

Step 3: Consider the HSA factor

If you have a Health Savings Account through an HSA-eligible high-deductible health plan at work, this single factor often dominates the decision.

HSA contribution rule: You cannot make HSA contributions after enrolling in any part of Medicare (including Part A).

For people actively maxing out HSA contributions:

2026 HSA contribution limit (individual coverage): $4,400
HSA contribution limit (family coverage): $8,750
Plus $1,000 catch-up contribution at age 55+

If you’re 65 and contributing $5,400/year to an HSA, that contribution has tax-advantaged value (deduction now, tax-free growth, tax-free qualified withdrawals). Losing the ability to contribute is a meaningful cost.

If HSA contributions matter to you, the typical play is:

Delay Part A enrollment until you stop contributing to the HSA
Note: if you’re already receiving Social Security retirement benefits, you’re automatically enrolled in Part A and can’t delay it
When you eventually enroll in Part A, you can do so retroactively up to 6 months — meaning Part A coverage starts 6 months in the past, retroactive to whenever you became eligible. This 6-month retroactive activation makes the HSA contribution timing tricky if you’re applying for Social Security after 65.

If HSA contributions don’t matter (you’re not contributing, or your employer plan isn’t HSA-eligible), enroll in Part A at 65. It’s free and creates a useful secondary payer for hospital coverage.

Step 4: Plan the eventual transition

Whatever you decide for the working period, plan how you’ll transition to full Medicare when you eventually retire or lose coverage.

The Special Enrollment Period (SEP) gives you 8 months from the date employer coverage ends to enroll in Part B without penalty. To use the SEP, the coverage must have been based on current employment (not COBRA, not retiree coverage). Your spouse’s employer coverage also qualifies if you were covered as a dependent.

Enroll early in the SEP, not at the deadline. Coverage takes effect the month after you apply, so applying in month 1 of the SEP gives you Part B coverage starting in month 2. Applying in month 7 of the SEP gives you Part B coverage starting in month 8 — leaving 7 months of potentially uncovered time.

Part D requires its own action. When employer coverage ends, you have 63 days to enroll in a Part D plan to avoid late enrollment penalties — a separate, shorter window than the Part B SEP. Don’t forget this. Many people focus on Part B and lose track of Part D timing.

Step 5: Coordinate with your spouse

If your spouse is covered on your employer plan and they’re also approaching or past 65, the coverage decisions interact.

Both spouses still on employer plan: No Medicare action needed for the spouse who’s not the employee, as long as employer coverage continues. The spouse can delay Medicare enrollment based on the employee’s current employment SEP rules.

One spouse retires, other continues working: The retiring spouse should enroll in Medicare during their SEP (triggered by losing the employer coverage). The continuing-working spouse stays on the employer plan if eligible.

Both spouses retire or lose coverage: Both enroll in Medicare during their respective SEPs. Time the enrollments to align so both have coverage starting the same month.

Disabled spouse on Medicare already: If your spouse is under 65 and on Medicare due to disability, they’re already enrolled. Your decision focuses on your own coverage; theirs is independent.

Common scenarios

Scenario A: Solo professional, 65, working at 100-person company, individual coverage costing $250/month

Employer plan is primary (20+ rule)
HSA contribution: not applicable
Math: Employer plan is cheaper than Medicare equivalent. Skip Part B. Enroll in Part A only (free). Plan SEP enrollment when work eventually ends.

Scenario B: 67-year-old at 12-person company

Medicare is primary (under 20 rule)
Need to enroll in Part B at 65 to avoid gaps and penalties
Employer plan becomes secondary
This is a common situation where people accidentally delay Part B and accumulate penalties

Scenario C: 65-year-old maxing HSA contributions at 30-person company

Employer plan is primary (20+ rule)
HSA contribution worth several thousand per year
Decision: delay all Medicare enrollment (including Part A) until HSA contributions stop. Coordinate carefully with Social Security retirement claiming.

Scenario D: 70-year-old with employer plan plus working spouse on the same plan

Currently on employer plan as primary
When they eventually retire: SEP starts, both enroll in Medicare
Critical: if they have a paid-up Medigap policy from a brief earlier Medicare period, check whether it can be reactivated. Otherwise, plan a fresh Medigap purchase during the new Medigap Open Enrollment Period that begins with Part B effective date.

Tax implications worth knowing

Medicare premiums are deductible as medical expenses if your total medical expenses exceed 7.5% of adjusted gross income. For most working people, this threshold isn’t reached, so Medicare premiums aren’t deductible.

If you’re self-employed, your situation is different — self-employed individuals can deduct their Medicare premiums (Parts B, D, and Medigap) as a business expense, similar to other health insurance premiums. This deduction is on Schedule 1 of your tax return, not Schedule A.

If your income is high enough to trigger IRMAA (Income-Related Monthly Adjustment Amount), your Part B and Part D premiums will be higher than the standard amounts. The 2026 IRMAA tiers start at $109,000 for single filers and $218,000 for joint filers (based on tax returns from 2024). Working high-income earners are common IRMAA targets.

Bottom line

Working past 65 doesn’t have to be complicated, but it does have to be deliberate. Determine your employer size, evaluate cost trade-offs, factor in HSA contributions if applicable, and plan the transition timing carefully. The biggest mistakes — like delaying Part B at a small employer, or accidentally losing HSA eligibility — are easy to avoid with a structured walk-through. If your situation is genuinely complex, a benefits consultant or fee-only financial advisor can usually clarify the right path for $200–$400 of consultation, well worth it given the lifetime cost of getting it wrong.

Common questions

Should I take Part A even if I'm staying on employer coverage? +

Almost always yes. Part A is free for anyone with 40+ work credits (10 years of Medicare-taxed earnings). Having Part A as secondary coverage to your employer plan can reduce hospital out-of-pocket costs in some situations and creates no downsides except one: if you have an HSA, you cannot continue HSA contributions after enrolling in Part A. If you're actively contributing to an HSA, this is the one reason to delay Part A enrollment.

What if my spouse is on my employer plan? +

Your spouse's coverage depends on whether you stay enrolled in the employer plan. If you stay on the plan and your spouse remains a dependent, no change. If you drop your employer plan to enroll in Medicare, your spouse may lose coverage too — depending on the plan's rules. Some employers allow non-Medicare spouses to remain on the plan even if the primary employee leaves; others don't. Check with HR before making changes that could affect your spouse.

Can I contribute to an HSA if I'm on Medicare? +

No. Medicare enrollment (Part A or Part B) makes you ineligible to contribute to a Health Savings Account. You can keep using your existing HSA balance, but no new contributions. This is the main reason some people delay Part A enrollment past 65 — to maintain HSA eligibility while still working with employer coverage that includes an HSA-eligible high-deductible health plan.

What happens if I don't enroll in Medicare and lose employer coverage at 67? +

You'll have a Special Enrollment Period — 8 months from when employer coverage ends — during which you can enroll in Parts A, B, and D without late enrollment penalties. Most people enroll in the first 1-2 months of the SEP so coverage is continuous. If you go past the 8-month SEP, you'll wait until the next General Enrollment Period (January 1 – March 31) and likely face penalties.

Will my employer plan be primary or secondary to Medicare? +

Depends on employer size. Employers with 20+ employees: the employer plan is primary, Medicare is secondary. You can delay Part B enrollment without penalty. Employers with under 20 employees: Medicare is primary, employer plan is secondary. You should generally enroll in Part B at 65 to avoid coverage gaps and penalties. Self-employed and sole proprietor situations: Medicare is generally primary; enroll at 65.