Social Security and RMDs: How Required Minimum Distributions Affect Your Benefits

Here is a detail that catches retirees by surprise: required minimum distributions from your traditional IRA or 401(k) do not just create a tax bill on their own — they also make more of your Social Security taxable. The mechanism is the IRC §86 provisional income formula, which counts IRA withdrawals (including RMDs) as ordinary income that flows into the same calculation that determines how much of your SS benefit is subject to federal tax. When your RMDs are large enough to push provisional income above the threshold, up to 85 cents of every Social Security dollar you receive is taxable income.

SECURE 2.0 (P.L. 117-328, December 2022) pushed back the RMD start age to 73 for those born 1951–1959, and to 75 for those born 1960 or later.¹ That delay gives more time to do Roth conversions and reduce future mandatory distributions. But for people with substantial pretax IRA balances, even a reduced first RMD can be enough to push provisional income well above the 85% threshold — regardless of when you claim Social Security.

How RMDs feed into the Social Security tax formula (IRC §86)

Social Security benefits are taxed under IRC §86 using provisional income — not your taxable income after deductions, and not your total gross income. The formula is:²

Traditional IRA and 401(k) withdrawals, including RMDs, land directly in AGI. The thresholds that determine how much of your SS is taxable were set by Congress in 1983 and 1993 and have never been adjusted for inflation:

Because these thresholds have never been updated for inflation, a growing share of retirees now find most of their SS taxable — even those with moderate income. A first RMD from a $600,000 IRA is roughly $22,000–$24,000 per year. Add other income and half of SS, and provisional income crosses the 85% ceiling for most retirees in one step.

SECURE 2.0 changed the timing: RMD start ages by birth year

Important: SECURE 2.0 §325 eliminated RMDs from Roth 401(k) and Roth 403(b) accounts starting January 1, 2024.³ Roth IRA balances have never required RMDs during the owner's lifetime. This matters for the planning calculus: Roth balances do not create provisional income in retirement, making Roth conversions before RMD start one of the most powerful tools available.

The stacking problem: when SS and RMDs land in the same year

If you claim Social Security at 70 and RMDs begin at 73, you have a three-year window where you receive full SS income with no mandatory IRA withdrawals — useful time for strategic distributions and Roth conversions. But at age 73, both income streams arrive simultaneously. For someone with a $700,000 IRA projected to grow at 6% for five years (to ~$936,000), the first RMD at age 73 would be roughly $35,300 per year (using the IRS Uniform Lifetime Table divisor of 26.5). Stack that on top of $30,000 in other income and half of a $42,000 annual SS benefit — and provisional income hits $86,300 for a married couple, well above the $44,000 MFJ ceiling. All 85% of their SS becomes taxable.

Claiming Social Security earlier reduces monthly SS, which lowers the ½-SS component of provisional income. But the RMD amount is determined by IRA balance — it is the same regardless of when you claim SS. For most retirees with large IRA balances, even the reduced ½-SS from early claiming still leaves provisional income well above the 85% threshold. The calculator below shows exactly where your numbers fall.

SS + RMD Provisional Income Calculator

Projects your first RMD, calculates provisional income at each claiming age, and shows how much of your Social Security will be taxable when RMDs begin.

Four strategies to reduce the RMD–SS tax collision

1. Roth conversions before RMDs begin

Each dollar converted from a traditional IRA to a Roth IRA reduces your future RMD balance — and Roth assets generate no RMDs at all during the owner's lifetime. Converting in years before RMDs start (when income may be lower and tax brackets more favorable) can reduce the stacking problem permanently. Converting $50,000/year for five years, for example, removes roughly $67,000 in future first-year RMDs assuming 6% growth — and eliminates all RMDs on those dollars forever. See the Roth conversion window calculator for annual conversion amounts and break-even analysis.

2. Qualified charitable distributions (QCDs)

Once you reach age 70½, you may direct up to $111,000 per year (2026 limit) directly from your traditional IRA to a qualifying charity.⁴ The distribution satisfies your RMD requirement and is excluded from AGI entirely — it never enters provisional income. For charitably inclined retirees, QCDs are the most efficient tool for lowering SS taxation in RMD years: a $20,000 QCD reduces your RMD that counts in provisional income by $20,000, which can shift 85% of that amount out of taxable SS territory at typical marginal rates. A spouse can do a separate $111,000 QCD from their own IRA.

3. Roth 401(k) and 403(b) rollovers to Roth IRA

SECURE 2.0 §325 eliminated RMDs from Roth 401(k) and Roth 403(b) accounts starting in 2024.³ If you still hold Roth 401(k) balances with former employers, rolling them into a Roth IRA preserves this RMD-free status. These balances will never create provisional income in retirement — and the rollover itself is tax-free (Roth-to-Roth).

4. Income smoothing: strategic IRA withdrawals before RMD start

Rather than letting your IRA compound until mandatory distributions force large taxable events, you can take voluntary withdrawals in lower-income years to reduce the future RMD balance. This is most useful in the gap years between retirement and SS claiming — a period when earned income has stopped, SS hasn't started, and your marginal bracket may be temporarily low. Withdrawing enough each year to stay within the 12% or 22% bracket flattens the distribution curve and reduces the provisional income spike when RMDs begin. Coordinate with Roth conversions for maximum effect.

When delaying Social Security to 70 still wins despite RMD stacking

For most people, the RMD–SS stacking problem is real but does not reverse the arithmetic of delaying SS. Consider three reasons:

• Equal tax impact at high balances: If your IRA is large enough that RMDs push provisional income above the 85% ceiling at every claiming age, then the SS taxable percentage is the same whether you claim at 62 or 70. The delay-to-70 break-even analysis holds unchanged.
• Survivor benefit magnification: A higher base SS benefit — achieved by delaying — means a larger survivor benefit for a surviving spouse. The 85% taxability applies to a larger absolute amount, but so does the after-tax income the survivor receives. For married couples where the higher earner delays, the survivor benefit case often overrides the tax optimization.
• COLA compounding on a larger base: Annual COLA increases compound on the claimed benefit. Delaying to 70 locks in a 24% larger base (for FRA=67), so each 2–3% COLA adds more income each year — including the years when RMDs are at their largest. The math over a 20-year horizon usually favors delay for people in reasonable health.

Where the stacking problem does change the calculus: if you are in the narrow range where claiming at 62 keeps provisional income below the 85% ceiling but claiming at 70 crosses it, you face a genuine trade-off between higher gross SS income and higher SS taxation. That is a case for professional modeling, not a rule-of-thumb answer.

1. IRS — Required Minimum Distributions FAQs. SECURE 2.0 (P.L. 117-328, §107): RMD age 73 for those born 1951–1959; age 75 for those born 1960 or later.
2. IRC §86 — Social Security and Tier 1 Railroad Retirement Benefits. Provisional income thresholds: $25,000 / $34,000 (single); $32,000 / $44,000 (MFJ). Enacted Social Security Amendments of 1983; upper tier added OBRA 1993. Never adjusted for inflation. IRS Publication 915 contains the full calculation worksheet.
3. IRS — Retirement Topics: Required Minimum Distributions. SECURE 2.0 §325: Roth 401(k) and Roth 403(b) accounts no longer subject to RMDs beginning January 1, 2024. Roth IRAs have never required lifetime RMDs.
4. IRS — Qualified Charitable Distributions. 2026 QCD limit: $111,000 per individual per IRS Rev. Proc. 2025-32. QCDs excluded from AGI; count toward RMD satisfaction. Eligible at age 70½.
5. IRS Publication 590-B — Distributions from Individual Retirement Arrangements. IRS Uniform Lifetime Table (2022 update, effective for 2022+, unchanged for 2026): age-73 divisor 26.5; age-75 divisor 24.6.

RMD ages verified against SECURE 2.0 (P.L. 117-328) and IRS RMD FAQs. Provisional income thresholds verified against IRC §86. QCD limit verified against IRS Rev. Proc. 2025-32. RMD divisors from IRS Pub. 590-B (T.D. 9930, 2022 Uniform Lifetime Table update, unchanged for 2026). Roth 401(k) RMD elimination per SECURE 2.0 §325. Values current as of June 2026.