FEHB vs. Medicare for Federal Retirees: A Cost-Benefit Analysis
Use this guide to understand the assumptions, inputs, results, and next steps behind the calculator.
As a federal employee approaching age 65, you face one of the most critical retirement healthcare decisions: should you enroll in Medicare Part B or rely solely on your Federal Employees Health Benefits (FEHB) plan? The choice involves a trade-off. Adding Medicare Part B means paying an additional premium—projected to be around $185 per month in 2026 for most—but it can dramatically lower your out-of-pocket costs and provide more comprehensive coverage.
This calculator is designed specifically for federal retirees to compare the annual and lifetime costs of two primary scenarios: keeping FEHB alone versus combining FEHB with Medicare Part B. By analyzing your FEHB premiums, estimated out-of-pocket expenses, and income, you can make an informed decision that balances cost, coverage, and peace of mind for your retirement years. This choice will be a cornerstone of your overall federal retirement plan.
FEHB vs. FEHB + Medicare Part B: A Side-by-Side Comparison
When you turn 65, you are automatically eligible for premium-free Medicare Part A (Hospital Insurance) if you have enough work credits. The real decision revolves around Medicare Part B (Medical Insurance). Here’s how the two main options stack up for federal retirees.
| Factor | FEHB Only (with Part A) | FEHB + Medicare Part B |
|---|---|---|
| How it Works | Your FEHB plan remains your primary insurance for all medical services and prescriptions. | Medicare Part B becomes your primary insurer for outpatient services. FEHB acts as the secondary payer, "wrapping around" Medicare to cover deductibles, copays, and services Medicare doesn't cover. |
| Monthly Premiums | You only pay your retiree share of the FEHB premium. | You pay both your FEHB premium AND the monthly Medicare Part B premium (including any IRMAA surcharges). |
| Out-of-Pocket Costs | You are responsible for your FEHB plan's deductibles, copayments, and coinsurance. | Significantly lower. Many FEHB plans waive their deductibles, copays, and coinsurance for medical services when Medicare is primary, leading to near-100% coverage. |
| Doctor & Hospital Choice | You must use doctors and hospitals within your FEHB plan's network to maximize benefits (e.g., PPO, HMO). | You can see any doctor or visit any hospital in the U.S. that accepts Medicare. FEHB then covers its share, regardless of whether the provider is in the FEHB network. |
| Prescription Drugs | Covered by your FEHB plan's drug formulary. You do NOT need Medicare Part D. | Covered by your FEHB plan. FEHB drug coverage is almost always considered "creditable," meaning it's as good as or better than Part D. |
| Overseas Coverage | Most FEHB plans offer comprehensive coverage for medical care received outside the United States. | Original Medicare provides no coverage outside the U.S. You would rely on your FEHB plan for any overseas medical needs. |
The Medicare Part B Decision: Key Factors for Federal Retirees
For most federal retirees, enrolling in Medicare Part B is the recommended path due to superior coverage and lower financial risk, despite the extra premium. However, the "right" answer depends entirely on your personal situation. Consider these four critical factors.
1. Your Health and Expected Medical Usage If you are in excellent health and anticipate few medical needs, the high cost of the Part B premium might seem unnecessary. You might be comfortable paying the occasional FEHB copay. Conversely, if you have chronic conditions, require specialist care, or want to protect against a catastrophic diagnosis, combining FEHB with Part B is invaluable. With Medicare as the primary payer, many FEHB plans waive most out-of-pocket costs, which can save you thousands annually and protect your retirement savings.
2. Your Specific FEHB Plan's Benefits Not all FEHB plans interact with Medicare in the same way. You must check your plan's official brochure (Section 9) to see how it coordinates with Medicare. Many popular plans, like Blue Cross Blue Shield Standard, offer significant "wrap-around" benefits, waiving their own cost-sharing requirements. Some plans may even offer a partial reimbursement of your Part B premium. Understanding these specifics is essential to calculating your true net cost.
3. Your Retirement Income and IRMAA The cost of Medicare Part B isn't the same for everyone. Higher-income retirees pay more due to the Income-Related Monthly Adjustment Amount (IRMAA). This surcharge can make Part B significantly more expensive and might tip the scales in favor of sticking with FEHB only. Before deciding, you must calculate your potential IRMAA based on your total retirement income, which includes your pension, Social Security, and any investment withdrawals. This is especially critical for those pursuing a Fat FIRE lifestyle with high annual spending.
4. Plans for Post-Retirement Work If you or your spouse continue to work past age 65 for an employer with 20 or more employees and you are covered by that employer's group health plan, you can delay enrolling in Part B without penalty. However, once that employment ends, you will have an eight-month Special Enrollment Period to sign up for Part B. Missing this window can result in lifelong late-enrollment penalties.
Understanding IRMAA: How Income Affects Your 2026 Medicare Costs
The Income-Related Monthly Adjustment Amount (IRMAA) is an extra charge added to your Medicare Part B (and Part D) premiums if your income exceeds certain thresholds. The Social Security Administration determines your IRMAA based on the modified adjusted gross income (MAGI) from your tax return two years prior. For 2026 premiums, your 2024 MAGI will be used.
Below are the projected IRMAA thresholds and monthly surcharges for 2026. These are added on top of the standard Part B premium (projected to be ~$185/month).
Projected 2026 Medicare Part B IRMAA Surcharges
| 2024 MAGI (Single Filer) | 2024 MAGI (Married Filing Jointly) | Monthly Part B Surcharge | Total Monthly Part B Premium |
|---|---|---|---|
| ≤ $109,000 | ≤ $218,000 | + $0 | ~$185 |
| > $109,000 up to $137,000 | > $218,000 up to $274,000 | + ~$74.00 | ~$259 |
| > $137,000 up to $171,000 | > $274,000 up to $342,000 | + ~$185.00 | ~$370 |
| > $171,000 up to $205,000 | > $342,000 up to $410,000 | + ~$296.00 | ~$481 |
| > $205,000 up to $410,000 | > $410,000 up to $819,000 | + ~$407.00 | ~$592 |
| > $410,000 | > $819,000 | + ~$444.00 | ~$629 |
Note: These are projections based on 2024 figures and estimated inflation. Actual 2026 amounts will be set by CMS in late 2025.
Your MAGI includes your FERS or CSRS pension, Social Security benefits, retirement account withdrawals, capital gains, and other taxable income. A large Roth conversion or sale of property can easily push you into a higher IRMAA bracket for a future year.
The Math Behind Your Healthcare Cost Comparison
The calculator determines the most cost-effective option by projecting your annual and lifetime expenses under two scenarios. Here are the core formulas it uses.
First, it calculates your total annual Medicare Part B premium, including any income-based surcharges.
Total Annual Part B Premium = (Standard Monthly Premium + Monthly IRMAA Surcharge) × 12
Where:
- Standard Monthly Premium = The base Medicare Part B premium for the year (e.g., ~$185 in 2026).
- Monthly IRMAA Surcharge = The extra amount you pay based on your MAGI, as determined by the IRMAA brackets.
Next, the calculator determines the total annual cost for each of the two main scenarios.
Annual Cost (FEHB Only) = Your Annual FEHB Premium + Estimated Annual OOP (FEHB Only)
Annual Cost (FEHB + Part B) = Your Annual FEHB Premium + Total Annual Part B Premium + Estimated Annual OOP (FEHB + Part B)
Where:
- Your Annual FEHB Premium = The portion of the FEHB premium you pay from your annuity.
- Estimated Annual OOP = Your expected out-of-pocket costs for deductibles, copays, and coinsurance under each scenario.
Finally, the lifetime cost is projected by taking the initial annual cost and inflating it each year until your life expectancy, providing a long-term view of how much your money will need to last. You can use the how long will my money last calculator to see this impact in more detail.
Frequently Asked Questions for Federal Retirees
What happens if I don't enroll in Medicare Part B at 65?
If you don't enroll in Medicare Part B during your Initial Enrollment Period (the 7 months around your 65th birthday) and you don't have other creditable coverage from an employer where you are still actively working, you could face a late enrollment penalty. The penalty is 10% of the standard Part B premium for each full 12-month period you were eligible but not enrolled, and you pay it for the rest of your life.
Can I suspend my FEHB coverage instead of canceling it?
Yes. If you decide to enroll in a Medicare Advantage (Part C) plan, you can suspend your FEHB coverage. This allows you to re-enroll in FEHB during a future Open Season if you later decide to leave the Medicare Advantage plan. You cannot, however, be enrolled in both an FEHB plan and a Medicare Advantage plan at the same time.
How does FEHB work with Medicare Part A?
When you enroll in Medicare, premium-free Part A becomes your primary coverage for inpatient hospital stays, skilled nursing facility care, hospice, and home health care. Your FEHB plan then acts as secondary coverage, helping to pay for Part A deductibles and coinsurance, often resulting in very low out-of-pocket costs for hospital stays.
Do any FEHB plans help pay for my Medicare Part B premiums?
Yes, a growing number of FEHB plans offer a partial reimbursement of your Part B premium as an incentive for you to enroll. This is typically delivered as a credit to your bank account or a reduction in your FEHB premium. Check with specific FEHB plans during Open Season to see which ones offer this benefit.
Is it better to have FEHB + Medicare or a Medicare Advantage plan?
This is a complex choice. FEHB + Original Medicare offers maximum flexibility to see any doctor nationwide that accepts Medicare. A Medicare Advantage (MA) plan may have lower total premiums (some even have a $0 premium) but restricts you to a provider network (like an HMO or PPO) and may require prior authorization for services. For those who value provider choice and simplicity, FEHB + Original Medicare is often preferred.
As a military retiree, how does TRICARE For Life fit in?
If you are a military retiree eligible for TRICARE, your decision is simpler. At age 65, you must enroll in Medicare Parts A and B to become eligible for TRICARE For Life (TFL). TFL then acts as your secondary payer, wrapping around Medicare. You can choose to suspend your FEHB coverage to save on premiums, as the combination of Medicare and TFL provides excellent coverage.
If I add Part B, do I still need an FEHB plan with good drug coverage?
Yes. Medicare Part B does not cover most outpatient prescription drugs. Your FEHB plan's drug coverage will remain your primary source for prescriptions. You do not need to enroll in a separate Medicare Part D plan, and doing so can cause coordination problems.
Next Steps for Your Healthcare Decision
Choosing your healthcare coverage is a foundational part of your financial plan, impacting your budget and your retirement withdrawal strategy. Use the insights from this calculator to have a productive discussion with your family and financial advisor.
To continue your planning, estimate your total retirement needs with the federal retirement calculator or explore how different income streams affect your long-term plan with the retirement income calculator. If you have an HSA from prior high-deductible plan enrollment, our HSA retirement calculator can help you model its growth.
Last updated: July 2026