I am making IRMAA payments to Medicare. Is this extra tax deductable as an "Other Tax" , therefore not subject to the 7.5% threshold on the Medical/Dental expenses?

I'm not collecting Social Security, so the published cost of my Medicare is $134/mo.

My IRMAA for Medicare Part B and D is $269.50/mo.

Should I claim the $134/mo. as a "Medical Expense" (subject to 7.5% threshold) and claim the $269.50/mo. as a fully deductible "Other Tax" ?

My rationale is the IRMAA is indeed a tax based on income, whereas the Medicare cost is not.

Deductions & credits

Good thought but....

Medicare considers it a premium.  From the official Medicare site the amount is added to your premium

Your modified adjusted gross income as reported on your IRS tax return from 2 years ago is above a certain amount. If so, you’ll pay the standard premium amount and an Income Related Monthly Adjustment Amount (IRMAA). IRMAA is an extra charge added to your premium (emphasis is mine)

https://www.medicare.gov/your-medicare-costs/part-b-costs/part-b-costs.html

Also, If you were on social security, the IRMAA deductions are included on the 1099-SSA and when entered will transfer to the medical section.

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