Roth Conversion Calculator
The years between retirement and your first RMD (age 73 or 75) are the most valuable planning window most retirees never fully use. This calculator compares your lifetime tax bill — with and without converting traditional IRA assets to Roth — so you can see whether the upfront tax cost pays off for your numbers.
How the comparison works
Both scenarios are projected from your current age through age 90 using the IRS Uniform Lifetime Table (post-SECURE Act 2.0) and 2026 federal tax brackets.
- No-conversion scenario: Your traditional balance grows uninterrupted. RMDs begin at your RMD start age based on the full balance. Each year's federal + state tax on RMDs is accumulated.
- With-conversion scenario: Each pre-RMD year, the annual conversion amount shifts from traditional to Roth. Roth grows tax-free with no future RMDs. Your traditional balance — and future RMDs — shrinks proportionally.
- Upfront cost: The incremental federal + state tax you pay from adding conversions to your income each pre-RMD year. This is the real cost of converting.
- Net savings: RMD taxes saved (age RMD–90) minus upfront conversion cost. Positive = converting saves more than it costs; negative = you're converting too much or into too high a bracket.
- IRMAA triggers. If a conversion raises your MAGI above $109,000 (single) / $218,000 (MFJ) in 2026, Medicare Part B + D surcharges kick in two years later — adding $600–$5,000+/yr. One bracket jump can wipe out a year of conversion savings.
- Social Security taxation. SS benefits become 0–85% taxable as AGI rises. Conversions that push income above the $34K/$44K combined-income thresholds increase SS taxes — an additional upfront cost not reflected here.
- QCD offsets. If you're 70½ or older, Qualified Charitable Distributions let you satisfy RMDs tax-free via direct charitable gifts (up to $111,000/yr in 2026). This reduces the tax burden of not converting.
- Estate planning. Inherited Roth IRAs grow tax-free for 10 years under the SECURE Act 10-year rule. For legacy-focused retirees, conversions often win even when the pure tax math is close.
The Roth conversion window: why timing is everything
When you retire and before Social Security fully kicks in, most retirees are in their lowest income bracket since their 20s. This gap — typically 5 to 12 years — is the conversion window. Once RMDs start, your taxable income rises every year as the IRS Uniform Lifetime Table divisor shrinks and your balance (if well-invested) grows. Converting in the window locks in today's rates on money that would otherwise be distributed at tomorrow's (higher) effective rates.
A 65-year-old couple with $2M in traditional IRA and $60K of other income can convert approximately $140K/year before crossing into the 24% federal bracket. Converting for 8 years (ages 65–72) at the 22% marginal rate moves over $1.1M into Roth. Without conversions, that same money distributed as RMDs in their late 70s and 80s may face a stacked effective rate of 32%+ — because a larger account balance forces larger RMDs, which pile on top of Social Security income and can trigger IRMAA surcharges.
2026 federal tax brackets
The calculator uses 2026 rates (OBBBA-permanent + IRS Rev. Proc. 2025-32 inflation adjustment):
| Rate | Single — taxable income | Married filing jointly |
|---|---|---|
| 10% | Up to $12,400 | Up to $24,800 |
| 12% | $12,400 – $50,400 | $24,800 – $100,800 |
| 22% | $50,400 – $105,700 | $100,800 – $211,400 |
| 24% | $105,700 – $201,775 | $211,400 – $403,550 |
| 32% | $201,775 – $256,225 | $403,550 – $512,450 |
| 35% | $256,225 – $640,600 | $512,450 – $768,600 |
| 37% | Over $640,600 | Over $768,600 |
Standard deduction 2026: $16,100 (single) / $32,200 (MFJ). Source: IRS Rev. Proc. 2025-32; One Big Beautiful Bill Act (OBBBA), July 2025.
Related tools & guides
Get a specialist to run your actual numbers
This calculator models federal + state tax on conversions and RMDs. A fee-only RMD specialist layers in IRMAA bracket management, Social Security taxation, QCD integration, asset location, and estate goals — all of which shift the conversion decision. Free match with a specialist who works exclusively on retirement distribution planning.
Frequently Asked Questions
Does a Roth conversion reduce future RMDs?
Yes. Every dollar converted from a traditional IRA to Roth reduces the account balance the IRS uses to calculate your required minimum distributions. At age 73 the RMD divisor is 26.5 — converting $200,000 before RMD age reduces your first-year RMD by roughly $7,547. The reduction compounds over time because the Roth balance grows without generating future RMDs.
How much can I convert to Roth in 2026 without jumping into a higher tax bracket?
It depends on your filing status and other income. For married filing jointly: the 22% bracket top is $211,400 of taxable income (2026). With $60,000 of other income and the $32,200 standard deduction, your taxable income starts at $27,800, leaving roughly $183,600 of conversion capacity before hitting the 24% bracket. For single filers with $40,000 other income, the headroom is approximately $46,000. Use the calculator above with your specific numbers.
Can a Roth conversion trigger Medicare IRMAA surcharges?
Yes. IRMAA is based on MAGI from two years prior — a 2026 conversion affects 2028 Medicare premiums. The first surcharge tier begins at $109,000 single / $218,000 married filing jointly (2026 thresholds). Hitting Tier 1 adds roughly $2,000+ per person per year in Part B and Part D costs. See the IRMAA calculator to model Medicare surcharge exposure before deciding on a conversion amount.
Is it too late to do a Roth conversion at age 70 or 72?
No — conversions remain available until RMDs begin (age 73 for most people; 75 for those born in 1960 or later). Converting at 70–72 still shifts future RMD-generating balances into Roth's RMD-free structure. Once RMDs start at 73+, the IRS ordering rule (IRC §408(d)(3)(E)) requires taking the full annual RMD before converting any additional funds — but conversions above the RMD amount remain permitted. See Roth conversions after RMD age for post-73 strategy.
What is the break-even period for a Roth conversion?
Typically 8–15 years, depending on: (1) the tax rate difference between your conversion bracket and projected future RMD bracket, (2) investment returns on the Roth balance growing tax-free, and (3) whether conversion taxes are paid from outside funds — which produces a faster payback than paying taxes from within the conversion itself. Use the Roth conversion break-even calculator to project the crossover year for your numbers.
Do I have to take my RMD before converting to Roth?
Yes, once RMDs have started. Under IRC §408(d)(3)(E), the first dollars distributed from a traditional IRA each year are treated as the required minimum distribution — and RMDs cannot be rolled over or converted. You must satisfy your full annual RMD before any remaining distribution is eligible for Roth conversion. Attempting to convert an amount that includes RMD dollars is treated as an ineligible rollover, which triggers income tax plus a potential 10% penalty.