Medicare premiums are based on taxable income, and a sudden increase can raise your costs. A Roth conversion can spike your premiums temporarily, but they will decrease once your income returns to normal. Medicare has four parts with different services and costs. Premiums, deductibles, copayments, and coinsurance vary depending on your income and plan choice. Premiums are adjusted based on your modified adjusted gross income (MAGI) and can change each year. A Roth conversion can increase premiums, but future withdrawals from a Roth IRA won’t count toward income. Consult a financial advisor to help manage your Medicare costs during a Roth conversion.

Read more at Yahoo Finance: Will Converting $500k to a Roth IRA Affect My Medicare Premiums?