Tax Calculator
Roth Conversion Calculator: What It Calculates and How to Read the Result
Quick answer
A Roth conversion moves money from a pre-tax IRA or 401(k) to a Roth IRA, paying the tax today in exchange for tax-free growth and tax-free withdrawals forever — and no required minimum distributions for the original owner. The conversion is mathematically attractive when your current marginal tax rate is meaningfully lower than your projected future rate. For most households with $1M+ in pre-tax accounts, the years between retirement and the start of RMDs at age 73 are the lowest-bracket window of a financial life.
Conversions will be capped if your IRA cannot cover the requested amount.
Applies to charts and table.
If on, the conversion amount to Roth is reduced by taxes.
Taxes: Federal and state entries are treated as effective rates applied to the taxable conversion amount in the year of conversion. If "Pay taxes from IRA" is on, the net reaching Roth is reduced accordingly.
Growth: Returns compound annually at the blended rate implied by your allocation unless overridden in Advanced. No RMDs or penalties are modeled. Roth grows tax-free; pre-tax grows tax-deferred and is shown before any withdrawals/taxes.
Conversions automatically stop or are capped if the IRA balance cannot cover the requested amount.
- Tax drag / lifetime taxes: ~280,000
- Conversion path underperforms no-conversion baseline.
- High estimated tax cost from conversions.
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| Year | Age | IRA (No Conv) | IRA (Conv) | Roth | Total (Conv) | Annual Conversion | Taxes on Conversion | Assumed Return |
|---|---|---|---|---|---|---|---|---|
| 1 | 61 | $1,066,000.00 | $1,012,700.00 | $50,000.00 | $1,062,700.00 | $50,000.00 | $14,000.00 | 6.6% |
| 2 | 62 | $1,136,356.00 | $1,026,238.20 | $103,300.00 | $1,129,538.20 | $50,000.00 | $14,000.00 | 6.6% |
| 3 | 63 | $1,211,355.50 | $1,040,669.92 | $160,117.80 | $1,200,787.72 | $50,000.00 | $14,000.00 | 6.6% |
| 4 | 64 | $1,291,304.96 | $1,056,054.14 | $220,685.57 | $1,276,739.71 | $50,000.00 | $14,000.00 | 6.6% |
| 5 | 65 | $1,376,531.09 | $1,072,453.71 | $285,250.82 | $1,357,704.53 | $50,000.00 | $14,000.00 | 6.6% |
| 6 | 66 | $1,467,382.14 | $1,089,935.65 | $354,077.38 | $1,444,013.03 | $50,000.00 | $14,000.00 | 6.6% |
| 7 | 67 | $1,564,229.36 | $1,108,571.41 | $427,446.48 | $1,536,017.89 | $50,000.00 | $14,000.00 | 6.6% |
| 8 | 68 | $1,667,468.50 | $1,128,437.12 | $505,657.95 | $1,634,095.07 | $50,000.00 | $14,000.00 | 6.6% |
| 9 | 69 | $1,777,521.42 | $1,149,613.97 | $589,031.38 | $1,738,645.35 | $50,000.00 | $14,000.00 | 6.6% |
| 10 | 70 | $1,894,837.83 | $1,172,188.49 | $677,907.45 | $1,850,095.94 | $50,000.00 | $14,000.00 | 6.6% |
| 11 | 71 | $2,019,897.13 | $1,196,252.93 | $772,649.34 | $1,968,902.27 | $50,000.00 | $14,000.00 | 6.6% |
| 12 | 72 | $2,153,210.34 | $1,221,905.63 | $873,644.20 | $2,095,549.82 | $50,000.00 | $14,000.00 | 6.6% |
| 13 | 73 | $2,295,322.22 | $1,249,251.40 | $981,304.71 | $2,230,556.11 | $50,000.00 | $14,000.00 | 6.6% |
| 14 | 74 | $2,446,813.49 | $1,278,401.99 | $1,096,070.82 | $2,374,472.81 | $50,000.00 | $14,000.00 | 6.6% |
| 15 | 75 | $2,608,303.18 | $1,309,476.52 | $1,218,411.50 | $2,527,888.02 | $50,000.00 | $14,000.00 | 6.6% |
| 16 | 76 | $2,780,451.19 | $1,342,601.97 | $1,348,826.66 | $2,691,428.63 | $50,000.00 | $14,000.00 | 6.6% |
| 17 | 77 | $2,963,960.96 | $1,377,913.70 | $1,487,849.22 | $2,865,762.92 | $50,000.00 | $14,000.00 | 6.6% |
| 18 | 78 | $3,159,582.39 | $1,415,556.01 | $1,636,047.26 | $3,051,603.27 | $50,000.00 | $14,000.00 | 6.6% |
| 19 | 79 | $3,368,114.83 | $1,455,682.70 | $1,794,026.38 | $3,249,709.09 | $50,000.00 | $14,000.00 | 6.6% |
| 20 | 80 | $3,590,410.40 | $1,498,457.76 | $1,962,432.12 | $3,460,889.88 | $50,000.00 | $14,000.00 | 6.6% |
Taxes: Federal and state entries are treated as effective rates applied to the taxable conversion amount in the year of conversion. If "Pay taxes from IRA" is on, the net reaching Roth is reduced accordingly.
Growth: Returns compound annually at the blended rate implied by your allocation unless overridden in Advanced. No RMDs or penalties are modeled. Roth grows tax-free; pre-tax grows tax-deferred and is shown before any withdrawals/taxes.
Conversions automatically stop or are capped if the IRA balance cannot cover the requested amount.
What This Calculator Actually Answers
This calculator answers the fundamental Roth conversion question: at your current bracket versus your projected future bracket, is converting now (paying tax today) better than leaving the money in the traditional IRA to be taxed later? It projects the after-tax outcome under each path across a 20-year horizon.
For most pre-retirees and early retirees, the answer is yes — but the amount and pacing matter. A one-time large conversion almost always triggers higher-bracket tax and IRMAA cliffs. A multi-year ladder, calibrated to fill specific brackets each year, captures the strategy's value without the second-order costs.
How to Read the Result
The single most important number is the breakeven horizon — the year by which the Roth conversion strategy mathematically beats the do-nothing path, accounting for the tax paid upfront, the future tax avoided, and the foregone earnings on the tax dollars you paid early. For most conversions executed at the 12% or 22% bracket against a projected 24%+ future bracket, the breakeven is 8–15 years.
If you expect to live well beyond the breakeven horizon, the Roth strategy wins. If your remaining life expectancy is shorter (or if you intend to leave the IRA to charity, which pays no income tax), the conversion may not pay off for you specifically — though it can still pay off for your heirs.
Common Mistakes
- Converting all in one year. A single large conversion usually pushes through several tax brackets and triggers IRMAA cliffs — most of the value is captured by smaller annual conversions across 5–10 years.
- Paying conversion tax from the IRA being converted (which means you're converting less and missing the strategy's leverage). Pay the tax from taxable accounts where possible.
- Forgetting the 5-year rule. Each Roth conversion has its own 5-year clock for penalty-free withdrawal of the converted amount if you're under 59½. The contribution clock and the conversion clock are separate.
- Ignoring the IRMAA two-year lookback. A large conversion in 2025 triggers IRMAA premium surcharges in 2027 — most people don't anticipate this delayed cost.
- Converting without modeling the impact on Social Security taxation. The added income from the conversion can push more of your Social Security into the taxable range.
When This Calculator Is Not the Right Tool
This is a single-year conversion calculator. For multi-year ladder strategy — which is what actually produces the lifetime tax savings — use the Roth Conversion Bracket Analyzer 2026, which models the year-by-year sequence against bracket and IRMAA targets.
Frequently Asked Questions
Is there an income limit for Roth conversions?
No. Roth conversions have no income limit — that limit applies only to direct Roth contributions. Any household, at any income level, can convert from a traditional IRA to a Roth IRA. The conversion is fully taxable as ordinary income in the year of conversion.
When does a Roth conversion make sense?
The standard test: when your current marginal tax rate is meaningfully lower than your projected future rate. For most $1.5M+ households, the pre-RMD years (between retirement and age 73) are the lowest-bracket window. The window typically closes once Social Security claiming and RMDs begin to fill the lower brackets with mandatory income.
Can I undo a Roth conversion if I change my mind?
No. The Tax Cuts and Jobs Act of 2017 eliminated Roth conversion 'recharacterization' starting in 2018. Once you convert, the decision is irrevocable. This makes pre-conversion modeling especially important — you cannot back out if the conversion turns out to be larger than your bracket can absorb.
Should I pay the conversion tax from the IRA or from outside funds?
From outside funds where possible. If you pay the tax from the IRA (a withholding or partial distribution), you're effectively converting less — and missing the strategy's main lever. The dollars that fund the tax should ideally come from a taxable brokerage account or cash, not from the IRA itself.