Required minimum distributions do affect Social Security and Medicare, though not in the way many retirees expect. An RMD from a Traditional IRA, 401(k), or similar tax-deferred account will not shrink the Social Security benefit you earned. What it will do is count as ordinary income, which can make up to 85% of your Social Security benefits taxable and, two years later, push your Medicare Part B and Part D premiums into surcharge brackets that cost hundreds of dollars a month.
How RMDs Turn Social Security Into Taxable Income
The IRS decides how much of your Social Security is taxable using a figure called combined income: your adjusted gross income, plus any tax-exempt interest, plus half of your Social Security benefits for the year.1Internal Revenue Service. Publication 915 – Social Security and Equivalent Railroad Retirement Benefits RMDs flow straight into adjusted gross income, so every dollar you’re forced to withdraw lifts that combined income number.
The thresholds are set by statute and have not been adjusted for inflation since 1993.2Office of the Law Revision Counsel. 26 USC 86 – Social Security and Tier 1 Railroad Retirement Benefits For single filers, combined income between $25,000 and $34,000 makes up to 50% of your benefits taxable; above $34,000, up to 85% becomes taxable. For married couples filing jointly, the 50% tier runs from $32,000 to $44,000, and the 85% tier kicks in above $44,000.
An RMD of $15,000 to $20,000 is often enough to move a retiree from paying no tax on Social Security to paying tax on a large share of it. The 85% figure is a ceiling: the IRS will never treat more than 85% of your benefit as taxable, no matter how high your income climbs. Because RMDs are taxed as ordinary income rather than at capital gains rates, they can meaningfully raise the effective tax rate on your Social Security dollars.3Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs
How RMDs Raise Your Medicare Premiums
The Income-Related Monthly Adjustment Amount, or IRMAA, adds a surcharge to your Medicare Part B and Part D premiums once your modified adjusted gross income crosses set thresholds. The Social Security Administration bases the determination on your tax return from two years prior, so a large RMD in 2024 shows up as a higher Medicare premium in 2026.4Office of the Law Revision Counsel. 42 USC 1395r – Amount of Premiums for Individuals Enrolled Under This Part
2026 Part B Premiums With IRMAA
The standard Part B premium for 2026 is $202.90 per month. Above the base threshold, you pay more:5CMS. 2026 Medicare Parts A and B Premiums and Deductibles
- Individual up to $109,000 / joint up to $218,000: no surcharge, $202.90.
- Individual $109,001–$137,000 / joint $218,001–$274,000: $81.20 surcharge, total $284.10.
- Individual $137,001–$171,000 / joint $274,001–$342,000: $202.90 surcharge, total $405.80.
- Individual $171,001–$205,000 / joint $342,001–$410,000: $324.60 surcharge, total $527.50.
- Individual $205,001–$499,999 / joint $410,001–$749,999: $446.30 surcharge, total $649.20.
- Individual $500,000+ / joint $750,000+: $487.00 surcharge, total $689.90.
2026 Part D Surcharges
Part D prescription drug coverage carries its own surcharge at the same income breakpoints:5CMS. 2026 Medicare Parts A and B Premiums and Deductibles
- Individual up to $109,000 / joint up to $218,000: no surcharge.
- Individual $109,001–$137,000 / joint $218,001–$274,000: $14.50 per month.
- Individual $137,001–$171,000 / joint $274,001–$342,000: $37.50 per month.
- Individual $171,001–$205,000 / joint $342,001–$410,000: $60.40 per month.
- Individual $205,001–$499,999 / joint $410,001–$749,999: $83.30 per month.
- Individual $500,000+ / joint $750,000+: $91.00 per month.
At the top tier, the Part B and Part D surcharges together add $578.00 per month, close to $7,000 a year, on top of the standard premiums. IRMAA is deducted directly from your Social Security check, so a higher premium shows up as a smaller monthly deposit.
A Steeper Cliff for Married Filing Separately
Couples who file separately and lived together at any point during the year face a compressed schedule. Once individual income exceeds $109,000, the Part B surcharge jumps straight to $446.30, skipping the three middle tiers.5CMS. 2026 Medicare Parts A and B Premiums and Deductibles
When You Can Appeal IRMAA
You can ask the SSA to reduce an IRMAA determination by filing Form SSA-44, but only for specific life-changing events: marriage, divorce, death of a spouse, work stoppage or reduction, involuntary loss of income-producing property, loss of pension income, and employer settlement payments tied to bankruptcy.6Social Security Administration. Form SSA-44 – Medicare Income-Related Monthly Adjustment Amount – Life-Changing Event A larger-than-expected RMD is not on that list, so you generally cannot appeal a surcharge caused by the distribution itself.
The First-Year RMD Trap
When RMDs start depends on your birth date:7Federal Register. Required Minimum Distributions
- Born after January 1, 1951, but before January 1, 1959: RMDs begin at age 73.
- Born after January 1, 1959: RMDs begin at age 75.
You’re allowed to delay your very first RMD until April 1 of the year after you reach the applicable age. The catch is that your second-year RMD still has to come out by December 31 of that same year, so two distributions land in one tax year.8Internal Revenue Service. Retirement Topics – Required Minimum Distributions (RMDs) That one-time spike can push more of your Social Security into the 85% tier and set off IRMAA surcharges two years later. Taking the first distribution by December 31 of the year you reach the RMD age splits the income across two separate tax years.
Roth IRAs are not subject to RMDs during the original owner’s lifetime, and the same treatment now applies to designated Roth accounts inside employer plans.3Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs Qualified Roth withdrawals also stay out of the combined income calculation, which is why Roth balances are useful for controlling how much of your Social Security gets taxed.
Ways to Soften the Impact
Send RMD Dollars Straight to Charity
If you’re at least 70½, a qualified charitable distribution lets you send money directly from your IRA to a qualifying charity, up to $111,000 in 2026. The transfer counts toward your RMD but is left out of adjusted gross income entirely. Because it never appears as income, it doesn’t lift combined income for Social Security taxation and doesn’t factor into your IRMAA determination. The funds have to move directly from the IRA custodian to the charity; withdrawing first and donating later doesn’t qualify.
Convert to Roth Before RMDs Start
Moving Traditional IRA or 401(k) money to a Roth IRA is taxable in the year you convert, but the balance then grows tax-free and carries no lifetime RMD. Converting in the low-income years between retirement and your RMD start age shrinks the account balance that later drives mandatory withdrawals. Smaller RMDs mean less pressure on Social Security taxation and Medicare premiums. Keep the two-year IRMAA lookback in mind: a conversion in a given year sets the premium two years out, so early conversions age out of the lookback before your first Medicare-eligible year.
Take the First RMD in the Year You Turn the RMD Age
Skipping the April 1 grace period on your first distribution avoids doubling up two RMDs in a single tax year. Splitting the income across two calendar years can keep combined income below a higher Social Security taxation tier, and below an IRMAA threshold, in both years.
State Taxes Sit on Top of All of This
The combined income thresholds and IRMAA brackets above are federal. Roughly 41 states plus the District of Columbia do not tax Social Security benefits at all, and states that still tax them generally offer partial exemptions tied to income, filing status, or age, with several phasing the tax out. RMDs, however, are subject to state income tax wherever the state taxes retirement account distributions, with rates ranging from zero in no-income-tax states to above 13% in the highest brackets. Check how your state treats both Social Security and retirement account withdrawals before locking in a distribution strategy.