How IRS Filing Status Affects Medicare Part B and D Premiums

Medicare eligibility is evaluated on an individual basis, independent of IRS tax filing status. However, the premiums for Medicare Part B and Part D are influenced by income thresholds known as Income-Related Monthly Adjustment Amount (IRMAA), which vary according to tax filing status — single or married filing jointly. The IRS filing status itself does not affect eligibility but impacts the premium calculations based on reported income from two years prior to Medicare enrollment. For individuals enrolling in Medicare at age 65, the premiums will be based on income tax returns filed two years earlier. For example, enrollment in 2028 will reflect income reported in the 2026 tax return. IRMAA thresholds adjust annually, and currently, the income limit for single filers is approximately $106,000 while for married filing jointly it is about $212,000. Income exceeding these thresholds results in higher Medicare premiums. Taxpayers should consider consulting a tax professional to evaluate the financial implications of choosing between filing jointly or separately, especially as combined income dictates the IRMAA premium adjustments for married couples. Additionally, continuous employment with creditable employer-sponsored health coverage allows delayed Medicare enrollment, which can temporarily defer premiums. This overview highlights the importance of understanding both IRS filing status implications and Medicare premium structures to make informed decisions prior to Medicare enrollment. Current and potential Medicare beneficiaries would benefit from ongoing monitoring of policy updates regarding IRMAA thresholds and premium calculations, as these factors directly affect out-of-pocket costs.