Retirement & Freedom with Sharrie

The Interchange
FEHB → Medicare Transition Toolkit

FEHB and Medicare Part B don't have to be an either/or. This tool merges your numbers — income, plan, health needs — onto one track so you can see what enrolling actually costs you, and when your window opens.

FEHB MEDICARE PART B COORDINATED COVERAGE

Step 1 — Your situation

Tell us where you stand

Use your 2024 MAGI (from your 2024 tax return) — Medicare uses a two-year lookback, so that's the figure that sets your 2026 premium.

Include pension, TSP withdrawals, Social Security, and any Roth conversions
Some FEHB plans reimburse $800–$1,200/year — check your plan brochure
Postal Service Health Benefits (PSHB) enrollees who became Medicare-eligible after Jan 1, 2025 generally must enroll in Part B, unless an exception applies.
Active employment FEHB counts as employer coverage — you can delay Part B penalty-free until employment ends.

Step 2 — Your result

Where FEHB and Medicare meet for you

Based on 2026 Medicare Part B premiums and IRMAA brackets (figures approximate — confirm your exact bracket with SSA).

Starting point

—

—

Part B premium (with IRMAA)
$0/mo
Annual Part B cost
$0/yr
Net cost after FEHB reimbursement
$0/yr

Your enrollment path

Coverage coordination

Primary payer Secondary payer
IRMAA: this is a cliff, not a gradual scale — $1 over a threshold triggers the full next tier. If your MAGI rose in 2024 due to a one-time event (retirement, lump-sum TSP withdrawal, Roth conversion), you can request a reduction using SSA Form SSA-44 based on a life-changing event.
Your enrollment window: —

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Current law only, subject to change: figures reflect 2026 Medicare Part B premiums and IRMAA brackets based on 2024 MAGI, and current FEHB/PSHB coordination rules as of publication. IRMAA bracket boundaries and PSHB exception rules are complex and periodically revised — always confirm your exact premium with Social Security and your specific FEHB or PSHB plan brochure before making an enrollment decision. This tool is for educational purposes only and is not individualized financial, legal, or tax advice.