Medicare scenarios

How to read these scenarios

Each scenario uses the same data layer as the calculators. The point is not to predict your own result. The point is to show which fact changes the answer, which deadline matters, and which official page to open next. Use the linked calculator with your own numbers before you act.

Scenario 1: working past 65 with a large employer

A 66-year-old has active coverage from an employer with 25 employees, the plan is creditable, and the person has 40 work credits. The calculator recommends you can generally delay part b.

The employer size matters because a plan with 20 or more employees generally pays first for a worker age 65 or older. The person can usually delay Part B while the active coverage continues. The eight-month Special Enrollment Period starts when the coverage or employment ends, not when the person turns 65.

The trade-off is the Marketplace. Premium-free Part A generally ends premium tax credits, even if the person is still working. The calculator says the subsidy status is ends.

Next step: confirm the employer size and the creditable coverage notice, then use the Medicare vs ACA tool with your own dates. The working past 65 guide lists the proof to keep.

Scenario 2: creditable coverage, but the Special Enrollment Period ended

A person went 12 months without Part B and had creditable employer coverage. If the Special Enrollment Period was still open, the calculator counts no penalty. If the window had already ended, the same 12 months produce a penalty. That is the difference between the two results below.

Creditable coverage is not a permanent exemption. It can protect a delay while the Special Enrollment Period is available. Once the window closes, the months can count. The calculator shows the difference instead of assuming that creditable coverage always means zero.

Next step: ask Social Security for the exact date the Special Enrollment Period ended and the months it counted. Then use the Part B penalty calculator with those dates. The Special Enrollment Period guide explains the eight-month window.

Scenario 3: one dollar over the IRMAA line

A single filer has $137,000.00 of MAGI in the two-year lookback. The next dollar crosses into the next IRMAA tier. The calculator shows the current monthly surcharge, the annual cost, and the cost of crossing the line.

A Roth conversion adds the converted amount to MAGI in the year of the conversion. The Medicare premium can change two years later. The relevant question is not only the tax on the conversion, but whether the extra income crosses an IRMAA threshold in the lookback year.

The first surcharge tier starts at $109,001.00. The next tier starts at $137,001.00. Crossing that line adds $1,736.40 a year for one person. That is a Medicare premium change, not a tax rate.

Next step: measure the conversion headroom before you convert. Use the IRMAA cliff checker with the income figure SSA actually used. The Roth conversion and IRMAA guide explains the two-year trap.