Roth Conversion at 70, 71, or 72: Your Final Window Before RMDs

The Roth conversion window doesn't close gently. For most people born between 1951 and 1959, required minimum distributions begin at age 73 — and once they start, the IRS sets your minimum taxable income from the IRA each year whether you want it or not. If you're currently 70, 71, or 72, you have between one and three years to convert on your own terms before that shift happens. After RMDs begin, you must take the required distribution first, leaving less room to layer a conversion on top without crossing into a higher bracket.

This guide covers what's specific to the 70–72 window: how Social Security income narrows your conversion room, how IRMAA interacts with the two-year lookback at this stage, and how to size the final conversions that will shape your tax picture for the next 15–20 years.

How many pre-RMD years do you actually have?

Under SECURE 2.0 Act § 107, RMD age depends on birth year.¹ If you were born 1960 or later, RMDs don't begin until 75 — this guide applies to those born before 1960.

RMD age per SECURE 2.0 § 107. Those born in 1951–1953 were already at or past RMD age before 2026. Note: age 72 in 2026 means your first RMD is due by April 1, 2027 (first year) or December 31, 2027 (if you take it in 2027 rather than deferring to 2028). Consult IRS Pub. 590-B for first-distribution deadline rules.

If you're 72, every month that passes is one month less to convert below your RMD threshold. The math changes faster than it seems.

What's different about 70–72 compared to earlier years

Social Security is almost certainly in play

Most retirees in the 70–72 range have already claimed Social Security — either at 62 (for the early benefit) or after delaying for maximum benefit. If you delayed to 70, you're receiving the largest possible monthly benefit. That SS income stacks on top of any Roth conversion, and at this income level, 85% of your Social Security benefit is typically taxable under IRC § 86.²

The practical effect: every dollar you convert gets added on top of SS income, and the 85% taxable portion of SS is already eating into your lower brackets. A couple with $60,000/year in Social Security and $10,000 in dividends has roughly $25,500 of taxable income before the first dollar of conversion — meaning the 12% bracket starts being used immediately, and the 22% bracket opens around $75,000 in annual conversions (see worked example below).

This is meaningfully tighter than the pre-SS years (say, ages 62–67) when many retirees had near-zero taxable income and could fill most or all of the 12% bracket before any conversion landed in 22%.

IRMAA is already two years into your lookback

At 70–72, you've been on Medicare for 5–7 years. Your 2026 Medicare premiums are based on your 2024 MAGI — already set. What you convert in 2026 will affect your 2028 premiums. The IRMAA lookback is a known, manageable constraint at this stage, not a surprise. The 2026 Tier 1 IRMAA threshold is $218,000 MAGI for married filing jointly or $109,000 for single filers; crossing it costs $1,148/person/year in Part B and D surcharges.³

How much can you actually convert at 70–72?

Step 1: Calculate your non-conversion taxable income

List every income source that will appear in your MAGI regardless of whether you convert this year:

• Social Security benefits (85% of gross SS is typically taxable at this income level; verify your specific provisional income using IRC § 86 thresholds — $32K–$44K combined income range for MFJ)
• Dividends and interest from taxable accounts
• Required minimum distributions from any inherited IRAs you're already taking
• Pension or annuity income
• Part-time work or self-employment

Subtract the standard deduction: $32,200 for married filing jointly plus $1,650 for each spouse age 65 or older = $35,500 for a couple where both are 65+. Single filers: $16,100 + $2,050 for age 65+ = $18,150.⁴

Step 2: Find your remaining bracket room

The 2026 federal income tax brackets (taxable income thresholds, from IRS Rev. Proc. 2025-32):

Subtract your non-conversion taxable income (Step 1) from the bracket ceiling you're targeting. The difference is how much you can convert before crossing that bracket. Factor in IRMAA: keep MAGI (not taxable income) below $218,000 MFJ / $109,000 single to stay at base Medicare premium rates — or make a deliberate decision to cross Tier 1 if the tax savings justify the $1,148/person/year surcharge.

Worked example: Victor and Helen, age 72

Victor (72) and Helen (71), both born 1954/1955. Victor has a $2 million traditional IRA. Both collected Social Security starting at age 70: Victor gets $40,000/year, Helen $22,000/year ($62,000 combined). They have $10,000/year in dividends from taxable accounts. No pension. Both on Medicare. MFJ.

Victor's RMD starts in 2027 — one year from now. This is their last full calendar year for unconstrained conversions.

Non-conversion income:

• Gross SS: $62,000. At their income level, 85% is taxable: $52,700
• Dividends: $10,000
• Total AGI items before conversion: $62,700
• Standard deduction (MFJ, both 65+): $35,500
• Taxable income before conversion: $62,700 − $35,500 = $27,200

Conversion scenarios for 2026:

Why the larger conversion deserves serious consideration:

This is their final pre-RMD year. In 2027, Victor must take his first RMD. Using 6.5% assumed IRA growth and the IRS Uniform Lifetime Table divisor of 26.5 at age 73:⁵

• No conversion in 2026: IRA grows to ~$2,130,000. Year-1 RMD = $2,130,000 ÷ 26.5 = $80,377
• $155,000 conversion in 2026 (just under IRMAA Tier 1): IRA = $1,845,000 × 1.065 = ~$1,965,000. Year-1 RMD = $1,965,000 ÷ 26.5 = $74,151

That $155,000 conversion reduces year-1 RMD by $6,226. But the more important effect plays out over decades: the entire trajectory of RMD income is lower, compounding throughout retirement. The $155,000 in the Roth account grows tax-free and is never subject to RMDs, leaving the next generation a tax-free inheritance rather than a 10-year mandatory IRA withdrawal schedule.

The widow bracket: why this matters beyond your own tax rate

For married couples, one of the strongest arguments for aggressive conversion at 70–72 is the single-filer bracket problem. When one spouse dies, the survivor files as Single (or as Qualifying Surviving Spouse for up to two years). Single filer brackets are approximately half of MFJ — but the income doesn't drop by half.

Consider Victor and Helen's situation after Victor dies. Helen files Single. She receives a survivor benefit equal to Victor's SS ($40,000). She inherits Victor's IRA and rolls it into her own, taking RMDs beginning at her own RMD age. If she's 72 when Victor dies, she'll face RMDs within a year — but now the RMD is taxed against single brackets that cap the 12% bracket at $50,400 and the 22% bracket at $105,700. The IRMAA Tier 1 threshold also drops to $109,000 for singles.

Converting now — while both spouses are alive and using the full MFJ brackets — is the most direct hedge against this risk. Every dollar moved to Roth at 22% today is a dollar that will never appear as a forced RMD under the surviving spouse's compressed single-filer brackets.

The RMD-first rule in your first RMD year

A common mistake at age 72: assuming you can do a large conversion in the same year your RMDs begin at 73. The IRS requires that your RMD be satisfied before any Roth conversion is processed from the same account. In Victor's case, the 2027 RMD of ~$74,000–$80,000 must come out first — and that alone may push MAGI close to the IRMAA Tier 1 threshold before any deliberate conversion. The conversion room available in 2027 is thus significantly smaller than in 2026.

This is why 2026 is Victor and Helen's most important planning year. The last pre-RMD year typically offers the largest unconstrained conversion room.

Frequently asked questions

Can I do a Roth conversion at 70 if I'm already on Social Security?

Yes. There's no age ceiling on Roth conversions and no rule that stops you because you're collecting SS. The practical constraint is that SS income stacks on top of the conversion, filling your lower brackets faster and making IRMAA more likely to trigger at higher conversion amounts. The Social Security and Roth conversion guide covers the combined income formula and effective rate multipliers in detail.

Is it too late to do a meaningful Roth conversion at 72?

No — and for most people with substantial IRA balances, this is one of the most consequential conversion years precisely because it's the last one before RMDs. A 72-year-old with a $2M IRA who does a $155,000 conversion in the final pre-RMD year meaningfully reduces every future RMD and changes the trajectory of their lifetime tax bill. "Too late" is relative; even one year of conversion changes the math.

Do I have to take an RMD at 72?

If you were born 1954–1956, your RMD age is 73. At 72, you're not yet required to take distributions — this year you can convert freely. The first RMD is due by April 1 of the year after you turn 73. Those born before 1954 are already past RMD age; see the post-RMD conversion guide.

Should I delay Social Security to 70 to maximize Roth conversions earlier?

Delaying SS to 70 is often recommended for the highest-earning spouse regardless of Roth strategy — the 8%/year delayed credit (from FRA to 70) plus lifetime inflation adjustments typically outperform early claiming for most people. The Roth conversion benefit of delaying SS is secondary but real: from ages 65–69, you can convert much larger amounts with no SS income eating into your low brackets. By 70, both strategies (max SS + max Roth conversion) are running simultaneously — the conversion room is tighter but the SS income is also at its maximum.

Can I still contribute to an IRA at 70-72 if I have earned income?

Yes. There's no age limit on traditional IRA contributions (the age-70½ limit was removed by SECURE Act 2019) or Roth IRA contributions, provided you have earned income and your MAGI is below the Roth contribution phase-out ($146,000 single / $230,000 MFJ for 2026 — verify current year). However, IRA contributions are limited to $8,000/year at age 50+ versus potentially hundreds of thousands in Roth conversions — so conversion is far more impactful for people with large IRA balances.

What if my spouse is much younger — does that change the calculus?

Significantly. If your spouse is 10+ years younger, your RMD is calculated using the Joint Life Expectancy Table (a separate IRS table with larger divisors), which reduces the required annual distribution. A larger age gap means smaller RMDs. But it also means your spouse will outlive you by many years and face a long stretch of single-filer taxation on inherited IRA assets — making pre-death conversion even more valuable from a beneficiary planning standpoint. A specialist can model the joint vs. single life expectancy RMD comparison for your situation.

What about Roth conversions after 73 — is it worth it then?

Yes, but within narrower constraints. Once RMDs begin, you must satisfy the RMD first from each account before converting any additional amount. The RMD itself is taxable but cannot be converted — only amounts above the RMD can go to Roth. For the mechanics and whether it still makes sense financially, see the post-RMD Roth conversion guide.

The bigger picture: your final three years

For a 70-year-old with $2M in a traditional IRA, three years of meaningful conversion could move $400,000–$550,000 to Roth before RMDs begin. That permanently changes the RMD calculation, reduces the widow bracket exposure, and creates a tax-free inheritance rather than a mandatory 10-year withdrawal clock for your heirs.

But the conversion size needs to account for what's actually in your brackets after Social Security — and the math is more complex at this stage than it was at 65. SS stacking, the two-year IRMAA lookback, state taxes, and the RMD projection all interact. The lifetime NPV calculator can model the two paths (convert vs. don't convert) at a high level. A fee-only advisor who specializes in this window can build the year-by-year schedule that optimizes across all of these simultaneously.

Sources

1. IRS: Retirement Topics — Required Minimum Distributions (RMDs) — confirms RMD age is 73 for individuals born 1951–1959 under SECURE 2.0 Act § 107, and 75 for those born 1960 or later. First RMD can be deferred to April 1 of the year following the year you turn 73.
2. IRS Tax Topic 423: Social Security and Equivalent Railroad Retirement Benefits — IRC § 86 combined income formula; thresholds for 50% and 85% SS taxability for married filing jointly ($32,000–$44,000 / above $44,000) and single ($25,000–$34,000 / above $34,000).
3. CMS: 2026 Medicare Parts B and D Income-Related Monthly Adjustment Amounts — 2026 IRMAA tier thresholds and per-person annual surcharges. Tier 1 MFJ threshold: $218,001 based on 2024 MAGI; surcharge $81.20/mo Part B + $14.50/mo Part D per person ($1,148/year per person).
4. IRS Rev. Proc. 2025-32 — 2026 federal income tax brackets and standard deduction amounts. Standard deduction MFJ: $32,200. Additional standard deduction age 65+: $1,650/qualifying individual (MFJ), $2,050 (single). 12% bracket MFJ ceiling: $100,800. 22% bracket MFJ ceiling: $211,400.
5. IRS Publication 590-B — Uniform Lifetime Table (T.D. 9930, effective 2022) — RMD divisors used for traditional IRA distributions. Age 73: divisor 26.5. Age 74: 25.5. Age 75: 24.6. Age 80: 20.2. No change from 2022 update for 2026.

RMD age per SECURE 2.0 Act § 107. IRMAA thresholds from CMS 2026 fact sheet; 2026 IRMAA is based on 2024 MAGI. Tax brackets from IRS Rev. Proc. 2025-32. SS taxability thresholds per IRC § 86. ULT divisors from T.D. 9930. Worked example uses 6.5% assumed IRA growth; actual results vary. Values verified May 2026.