Should Federal Retirees Enroll in Medicare Part B If They Keep FEHB? Costs, Risks, and When It Pays Off (2026)
Last reviewed: September 2026 · Educational, not individual advice
For most federal retirees, keeping FEHB and adding Medicare Part B is a cost trade, not a coverage requirement. In 2026 Part B costs $2,435 a year at the standard premium, more with IRMAA. It tends to pay off in heavy-care years, and FEP Blue Basic returns up to $800 of it. Here is the math.
If you are a federal retiree keeping FEHB and counting the months until 65, you are probably juggling FERS, TSP, maybe when to take Social Security, and a growing pile of mail about Medicare. The hard part is not finding an answer online. It is knowing what applies to you as a federal annuitant. This guide walks through how Medicare Part A and Part B work alongside FEHB, what your health costs look like with and without Part B, what happens if you skip it and change your mind, and what IRMAA means when your income stays high. We use round-number procedure examples so you can get a clear sense of scale.
Educational only, not enrollment, tax, or medical advice. Confirm everything with your FEHB brochure, OPM, SSA, and Medicare.
Why FEHB changes the Medicare Part B question
Most people lose employer health insurance when they retire. FEHB is unusual: if you qualify (typically an immediate annuity and five consecutive years in FEHB before retirement), you can keep a group plan, and the government still pays a large share of the premium. By law that is roughly 72% of the program-wide weighted average, capped at 75% of your plan's premium. Most FEHB plans bundle medical and prescription coverage, Open Season lets you switch plans every year, and every plan has an annual out-of-pocket maximum.
None of that makes FEHB free. It explains why federal retirees usually keep FEHB and then decide whether to layer Medicare on top. So at 65 the question is rarely "FEHB or Medicare?" It is "Do I need Medicare Part B, and what do I give up if I skip it?"
What federal retirees actually spend on health care
Numbers help you breathe. You are not looking for precision to the dollar; you want a sense of scale.
- FEHB premiums for 2026: OPM reported the average enrollee share rising about 12.3% (program average; your plan may differ), with 47 carriers offering 132 plan options. Source: OPM, Federal Benefits Open Season Highlights, 2026 plan year.
- Medicare beneficiaries overall: people with Medicare spent an average of $6,459 out of pocket in 2023 on premiums plus services, according to KFF's analysis of the Medicare Current Beneficiary Survey. That average includes people who used very little care and people who used a great deal. For the gaps behind that number, see what Medicare does not cover.
FEHB with Part A only vs. FEHB with Part A and Part B
Start with the roles. Part A (hospital) is premium-free at 65 for most people with 40 quarters of Medicare-covered work, which is common after a long federal career. Part B (doctor and outpatient care) has a monthly premium and a deductible. For 2026, CMS set the standard Part B premium at $202.90 a month and the Part B deductible at $283. If your income is high enough, Part B and Part D premiums carry income-related surcharges (IRMAA, covered below).
With Part A and Part B, Medicare usually pays first on covered outpatient and professional care, including physician services in the hospital. FEHB coordinates as secondary, and many plans waive or reduce deductibles, copays, and coinsurance when Medicare pays first.
Without Part B, you avoid the premium: about $2,435 a year per person at the 2026 standard rate, or $3,409 in the first IRMAA tier. But for the care Part B would cover, Medicare is not paying first. Your FEHB plan is primary, and you rely on its cost-sharing for doctor visits, imaging, and outpatient procedures. That can be fine or expensive depending on your plan and how much care you use.
So the comparison is not premiums alone. It is premiums plus how you use care, minus any Part B reimbursement your plan pays.
FEP Blue Basic vs Standard premiums (2026)
The Blue Cross Blue Shield Service Benefit Plan is the plan most federal retirees compare against, so we use it as the example throughout. Figures from OPM brochure RI 71-005 (2026), nationwide rates.
| Enrollment | FEP Blue Standard (2026) | FEP Blue Basic (2026) |
|---|---|---|
| Self Only | $188.32 biweekly / $408.02 monthly | $133.77 biweekly / $289.83 monthly |
| Self Plus One | $410.88 biweekly / $890.24 monthly | $319.25 biweekly / $691.71 monthly |
| Self and Family | $457.66 biweekly / $991.60 monthly | $356.86 biweekly / $773.20 monthly |
Light and moderate years: FEHB copays vs the Part B premium
OPM does not publish a national average for FEHB cost-sharing, so compare your own plan's rules to Part B's fixed premium. Illustrative FEP Blue Service Benefit Plan, Preferred office visits:
- Light year, 6 primary-care and 4 specialist visits on Basic: 6 × $35 + 4 × $50 = $410 in copays.
- Moderate year, 8 primary-care and 12 specialist visits on Standard: 8 × $30 + 12 × $40 = $720.
- Heavy year: imaging, hospital outpatient, or non-Preferred care can add much more.
In a light year, FEHB-only copays are often less than the annual Part B premium of about $2,435 before IRMAA. The picture changes in a heavy year.
Heavy years: what a surgery costs with and without Part B (illustrative)
We use four inpatient procedures as examples, not hospital quotes: CABG (bypass), knee replacement, spinal fusion, and a major cancer surgery. The goal is intuition for premiums versus a big one-time bill, not a replacement for your Explanation of Benefits.
Step 1: how the illustrative bill splits between Part A and Part B. Round-number, Medicare-approved-style amounts.
| Procedure (inpatient example) | Illustrative Part A hospital-related allowed | Illustrative Part B professional allowed |
|---|---|---|
| CABG (bypass) | $90,000 | $18,000 |
| Knee replacement (e.g., TKA) | $45,000 | $12,000 |
| Spinal fusion | $95,000 | $28,000 |
| Cancer surgery (major inpatient) | $55,000 | $22,000 |
Assumptions: Original Medicare, Preferred providers, FEP Blue Service Benefit Plan (brochure RI 71-005), one inpatient benefit period, days 1 to 60, 2026 Medicare amounts (Part A deductible $1,736; Part B deductible $283; 20% Part B coinsurance on allowed professional charges). With Part A only, the FEHB professional share uses Standard's $350 deductible plus 15% of the plan allowance, or Basic's $200 non-office surgeon copay plus 35% on an illustrative drugs-and-supplies slice (25% of the professional allowance as a proxy). With Part A and Part B, we assume FEHB wraps the Part B patient responsibility, so the net cost is mainly the Part A deductible. Confirm all amounts with Medicare and your carrier.
Step 2: approximate patient-paid totals.
| Procedure | FEHB Standard + Part A only | FEHB Basic + Part A only | FEHB + Part A + Part B (net if FEHB wraps the Part B share) |
|---|---|---|---|
| CABG | ~$4,734 | ~$3,511 | ~$1,736 |
| Knee replacement | ~$3,834 | ~$2,986 | ~$1,736 |
| Spinal fusion | ~$6,234 | ~$4,386 | ~$1,736 |
| Cancer surgery | ~$5,334 | ~$3,861 | ~$1,736 |
Outpatient-only procedures, multiple surgeons, non-covered services, or different networks would change these results. In a heavy year the gap between Part A only and Part A plus Part B runs roughly $1,250 to $4,500 in these examples, against a standard Part B premium of about $2,435 a year, or about $1,635 net for a FEP Blue Basic member after the $800 reimbursement described below.
What if you skip Part B and change your mind later?
This is the risk the premium comparison hides. As a retiree, your FEHB coverage does not count as coverage from current employment, so once you have retired there is no Special Enrollment Period. If you decline Part B at 65 and enroll later, you pay a late enrollment penalty of 10% of the standard premium for every full 12-month period you could have had Part B but did not. The penalty lasts for as long as you have Medicare, and it is added to whatever the premium is in that future year, not today's.
If you keep working past 65 with FEHB as an active employee, you can delay Part B without penalty and get an 8-month Special Enrollment Period that starts when your employment ends. Retirees who left service before 65 do not get that window.
One more timing rule: if you contribute to a Health Savings Account through a high-deductible FEHB plan, stop contributions at least six months before your Medicare coverage starts. OPM's guidance is clear that you cannot contribute to an HSA while enrolled in Medicare.
Sources: Medicare.gov, Avoid late enrollment penalties; OPM, Medicare.
Part B reimbursement changes the math
Several FEHB plans give money back to members who enroll in Part B. In 2026 FEP Blue Basic members with Medicare Part A and Part B can get up to $800 back per year through a Medicare Reimbursement Account, or $1,600 for a couple when both spouses have Medicare. GEHA and NALC plans also offer Medicare reimbursement accounts. FEP Blue Standard does not.
For a Basic member at the standard premium, that turns $2,435 into about $1,635 net. It also opens the Open Season move OPM itself suggests: once Medicare is primary, a lower-premium plan such as Basic may fit, because many plans waive deductibles, copays, and coinsurance when Medicare pays first. Moving from Standard to Basic on a Self Only enrollment saves about $1,418 a year in premium for 2026 before the reimbursement. Run your own plan's brochure; not every plan waives the same costs.
A hypothetical composite: Sam and Dan. Sam retires from NIH at 63 with a FERS annuity; Dan claims Social Security at 65. Their joint income in the IRMAA lookback year is about $190,000, so both pay the standard Part B premium. Both are on FEP Blue Basic. Two Part B premiums ($4,870) minus two reimbursements ($1,600) come to about $3,270 a year for near-zero cost-sharing on doctor and outpatient care. Their numbers are illustrative; yours will differ.
IRMAA: why a federal couple's Part B can cost $3,409 or more
Part B premiums are income-based. For 2026, Medicare looks at your 2024 modified adjusted gross income. Above $109,000 for a single filer or $218,000 for a joint return, the premium rises from $202.90 to $284.10 a month, which is $3,409 a year per person in that first tier. The top tier reaches $689.90 a month.
A FERS annuity, TSP withdrawals, a spouse's pension, and taxable Social Security all count toward that number. Federal couples in the DC and Baltimore area, where two long federal careers are common, often land near the $218,000 line without feeling wealthy. Retirement itself is a life-changing event that can support an appeal on Form SSA-44, and multi-year planning for Roth conversions and withdrawal order can keep future years under a threshold. We cover the mechanics in how IRMAA works and the two-year lookback and in Roth conversions in the gap years to manage IRMAA.
Who should probably skip Part B?
Part B is not automatic for everyone. Considerations that point toward declining it: you are in a top IRMAA tier so the premium is $650 or more a month per person, you are healthy with low expected use, your FEHB plan already has modest cost-sharing, and you have thought through the late enrollment penalty and accept it. Considerations that point toward enrolling: a chronic condition or an expected surgery, a plan that reimburses part of the premium, or the wish for near-zero cost-sharing in a year when something goes wrong. If you are thinking about dropping FEHB entirely for Medigap or Medicare Advantage, that is a different decision; see Medigap vs Medicare Advantage if you drop FEHB.
Run both scenarios with your plan brochure before Open Season.
Your Part B checklist before 65
- Confirm that FEHB carries into retirement: the five-year rule and immediate annuity eligibility.
- Calendar your Medicare enrollment windows, especially the Initial Enrollment Period around 65 if you are not on active employer coverage.
- Model IRMAA two years ahead. TSP withdrawals, taxable investments, Social Security taxation, and Roth versus traditional flows all feed the number, as does how much a federal employee needs to retire.
- Check whether your FEHB plan reimburses Part B and what it waives when Medicare is primary.
- Shop Open Season every year. Plan exits happen; 2026 had discontinued options with defaults announced by OPM.
- Weigh the premium, the penalty risk, and your likely out-of-pocket costs together before deciding.
Bottom line
You do not need a perfect prediction of health inflation. You need a decision framework: compare FEHB and Part B costs honestly, understand Part A only versus adding Part B in dollars and coordination, count any Part B reimbursement, pick FEHB options on total cost rather than premium alone, and fold IRMAA into your retirement income planning if you are in the higher-income bracket.
If you want the two scenarios modeled for your household, book a call.
FAQ: Medicare Part B and FEHB
Do I have to enroll in Medicare Part B if I keep FEHB?
No, if you are a non-postal annuitant. FEHB stays your primary coverage and no FEHB carrier reduces benefits because you declined Part B. Most Medicare-eligible Postal retirees are the exception: the PSHB program requires Part B to keep coverage. Confirm your status with OPM before you decide.
What happens if I skip Part B and enroll later?
You pay a late enrollment penalty of 10% of the standard premium for every full 12 months you could have had Part B, for as long as you have Medicare. Retiree FEHB does not count as current-employment coverage, so there is no special enrollment period once you have retired.
Does any FEHB plan reimburse the Medicare Part B premium?
Yes. In 2026 FEP Blue Basic returns up to $800 per member with Parts A and B, or $1,600 for a couple. GEHA and NALC plans also offer Medicare reimbursement accounts. FEP Blue Standard does not. For a Basic member the standard premium nets to about $1,635 a year.
How does IRMAA affect a federal couple's Part B cost?
2026 IRMAA uses 2024 modified adjusted gross income. Above $218,000 joint, each spouse pays $284.10 a month ($3,409 a year) instead of $202.90, rising to $689.90 in the top tier. FERS annuities, TSP withdrawals and Social Security all count. Retirement can support a Form SSA-44 appeal.
Can I switch to a cheaper FEHB plan once I have Part B?
Yes, at Open Season. When Medicare pays first, many FEHB plans waive deductibles, copays and coinsurance, so a lower-premium option may fit. Moving from FEP Blue Standard to Basic saves about $1,418 a year in Self Only premium for 2026, before the $800 Part B reimbursement.
Sources
- CMS, 2026 Medicare Parts A & B Premiums and Deductibles (Nov. 14, 2025): https://www.cms.gov/newsroom/fact-sheets/2026-medicare-parts-b-premiums-deductibles
- OPM, Federal Benefits Open Season Highlights, 2026 Plan Year: https://www.opm.gov/healthcare-insurance/healthcare/reference-materials/reference/federal-benefits-open-season-highlights-for-plan-year-2026.pdf
- OPM, Medicare: https://www.opm.gov/healthcare-insurance/healthcare/medicare/
- OPM, Blue Cross and Blue Shield Service Benefit Plan brochure RI 71-005 (2026): https://www.opm.gov/healthcare-insurance/healthcare/plan-information/plans/pdf/2026/brochures/71-005.pdf
- Medicare.gov, Avoid late enrollment penalties: https://www.medicare.gov/basics/costs/medicare-costs/avoid-penalties
- FEP Blue, Medicare reimbursement: https://www.fepblue.org/our-plans/medicare/medicare-reimbursement
- KFF, Key Facts About Health Care Affordability for People With Medicare: https://www.kff.org/medicare/key-facts-about-health-care-affordability-for-people-with-medicare/
Disclaimer: This article is general education only and is not legal, tax, medical, or individualized investment advice. Premiums, plan availability, and Medicare rules change. Confirm details with OPM, your FEHB carrier, SSA, Medicare, and your licensed professionals before enrolling or changing coverage.
Securities and investment advisory services offered through LPL Enterprise (LPLE), a Registered Investment Advisor, Member FINRA/SIPC, and an affiliate of LPL Financial. LPLE and LPL Financial are not affiliated with Allset Wealth.
