How RMDs Impact Your Taxes and Social Security

RMDs are taxed as ordinary income — and their impact goes well beyond just the tax on the distribution itself. Large RMDs can trigger a chain reaction that affects three other major costs.

Effect 1 — Federal Income Tax Bracket

RMDs add to your adjusted gross income and can push you from a lower bracket into a higher one. Even a modest RMD can be significant when combined with Social Security income, pension income, or investment distributions.

For a married couple, the difference between the 12% and 22% federal bracket in 2026 is roughly $89,075. A $20,000 RMD that pushes you over that threshold means paying 22% on the excess instead of 12% — an additional 10 cents on every extra dollar.

Effect 2 — Social Security Taxability

RMDs count toward your "combined income" calculation, which determines what percentage of your Social Security benefit is taxable. RMDs can push combined income above the $32,000 threshold (joint) and make up to 85% of your SS benefit taxable — when it might have been 0% or 50% without the RMD.

Effect 3 — Medicare IRMAA Surcharges

Medicare Part B and Part D premiums are based on your MAGI from two years ago. A large RMD in 2026 will affect your 2028 Medicare premiums. For married couples filing jointly, IRMAA surcharges begin at $212,000 MAGI (2026). A single large RMD can trigger these surcharges unexpectedly.