Before you do a Roth conversion, calculate the tax cost and make sure you’re converting at a lower rate than you’d pay in retirement. A well-timed conversion can save tens of thousands in taxes over your lifetime — but doing it in the wrong year wastes money.
7 Things to Know Before Converting
| # | Key Point | Why It Matters |
|---|---|---|
| 1 | You’ll owe income tax on the converted amount | The conversion amount is taxed as ordinary income |
| 2 | There’s no income limit on conversions | Anyone can convert, regardless of income |
| 3 | There’s no dollar limit per year | But converting too much pushes you into a higher bracket |
| 4 | You should pay taxes from outside the account | Using conversion funds to pay taxes reduces the benefit |
| 5 | The 5-year rule applies to conversions | Each conversion has its own 5-year clock for penalty-free withdrawal |
| 6 | Conversions are irreversible | As of 2018, you cannot “recharacterize” (undo) a Roth conversion |
| 7 | The optimal time is when your income is low | Gap years, early retirement, before RMDs and Social Security start |
Tax Cost by Bracket
| Amount Converted | 12% Bracket | 22% Bracket | 24% Bracket | 32% Bracket |
|---|---|---|---|---|
| $10,000 | $1,200 | $2,200 | $2,400 | $3,200 |
| $25,000 | $3,000 | $5,500 | $6,000 | $8,000 |
| $50,000 | $6,000 | $11,000 | $12,000 | $16,000 |
| $100,000 | $12,000 | $22,000 | $24,000 | $32,000 |
Plus state income taxes. Convert only enough to fill your current bracket — don’t overflow into the next.
Bracket-Filling Strategy Example
| Scenario | Single Filer, 2026 |
|---|---|
| Taxable income (without conversion) | $50,000 |
| Top of 22% bracket | $103,350 |
| Room to convert in 22% bracket | $53,350 |
| Tax cost of converting $53,350 | $11,737 (federal) |
| Benefit: $53,350 grows tax-free forever | No taxes on withdrawals, no RMDs |
Converting $53,350 fills the 22% bracket without spilling into 24%. This is the optimal amount.
Best Times to Convert
| Situation | Why It’s Optimal |
|---|---|
| Between jobs (low-income year) | Lower bracket = lower conversion tax |
| Early retirement (before Social Security + RMDs) | Income is at its lowest |
| Year of large deductions (medical, charitable) | Deductions offset conversion income |
| Market downturn | Convert when account value is temporarily low — same shares, less tax |
| Before expected tax rate increases | Lock in today’s lower rates |
| Starting a business with early losses | Business losses offset conversion income |
When NOT to Convert
| Situation | Why It’s a Bad Idea |
|---|---|
| Already in a high tax bracket | Paying 32-37% on conversions rarely makes sense |
| You’d need to use conversion funds to pay the tax | Reduces the Roth benefit significantly |
| You’ll need the money within 5 years | 5-year rule may trigger penalties on earnings |
| You’re over 72 and RMDs push you into high brackets | RMD income + conversion income = very high tax bill |
| You expect to be in a lower bracket in retirement | Pay less tax later by leaving it traditional |
| Conversion pushes you above ACA subsidy cliff | Could lose $5,000-$15,000 in health insurance subsidies |
Roth Conversion vs. Traditional Comparison
| Factor | Keep Traditional | Convert to Roth |
|---|---|---|
| Tax paid now | $0 | Tax on converted amount |
| Tax in retirement | Ordinary income rates on withdrawals | $0 — tax-free |
| Required minimum distributions (73+) | Yes — forced taxable withdrawals | No RMDs for Roth IRAs |
| Estate benefit | Heirs pay income tax on withdrawals | Heirs get tax-free withdrawals |
| Social Security taxation | Withdrawals increase combined income | Roth withdrawals don’t count |
| Medicare premium surcharges (IRMAA) | Withdrawals can trigger surcharges | Roth withdrawals don’t count |
Multi-Year Conversion Strategy
| Year | Taxable Income | Convert | Tax Bracket | Tax Cost |
|---|---|---|---|---|
| Year 1 (retire at 60) | $20,000 | $75,000 | 12-22% | ~$11,500 |
| Year 2 | $20,000 | $75,000 | 12-22% | ~$11,500 |
| Year 3 | $20,000 | $75,000 | 12-22% | ~$11,500 |
| Year 4 | $20,000 | $75,000 | 12-22% | ~$11,500 |
| Year 5 (start SS at 65) | $45,000 | $50,000 | 22% | ~$11,000 |
| Total converted | — | $350,000 | — | ~$57,000 |
Without conversions, RMDs on $350K at 73 could be taxed at 24-32% — costing $84,000-$112,000. Conversion saved $27,000-$55,000.
The Bottom Line
A Roth conversion is one of the most powerful tax planning tools in retirement — but timing is everything. The ideal strategy is to convert during low-income years (early retirement, between jobs, market downturns) using a bracket-filling approach. Pay the taxes from a separate account, spread conversions over multiple years, and avoid converting so much that you jump into a higher bracket or lose ACA subsidies. Done right, a multi-year Roth conversion ladder can save you tens of thousands in lifetime taxes.