What is a Roth IRA Conversion
A Roth IRA conversion is the process of moving money from a traditional IRA or 401(k) into a Roth IRA, paying income taxes on the converted amount now in exchange for tax-free growth and withdrawals in retirement.
A Roth IRA conversion is when you transfer money from a tax-deferred retirement account — a traditional IRA, 401(k), 403(b), or SEP IRA — into a Roth IRA. The converted amount is added to your taxable income in the year of the conversion, and you pay income taxes on it at your current rate. In exchange, that money grows tax-free and can be withdrawn tax-free in retirement.
There is no income limit on Roth IRA conversions — anyone can convert regardless of how much they earn. This distinction is important because there are income limits on direct Roth IRA contributions, which is why high earners use the backdoor Roth IRA strategy.
Why Convert to a Roth IRA?
The core logic: pay taxes now at a known rate so you never pay taxes on that money again.
Converting makes sense if you believe your tax rate will be higher in retirement than it is today. This is relevant when:
- You're currently in a low-income year (job transition, sabbatical, early retirement, market downturn losses)
- You expect tax rates to rise in the future (legislative risk)
- You have significant traditional IRA or 401(k) balances that will create a large RMD burden (Required Minimum Distributions) in your 70s
- You want to leave tax-free assets to heirs — Roth IRAs have no RMDs during the original owner's lifetime
How a Roth Conversion Works
- Request the conversion — contact your brokerage or financial institution and initiate a conversion from your traditional IRA to a Roth IRA (if converting a 401(k), you typically roll it to a traditional IRA first, then convert)
- Calculate the tax impact — the converted amount is added to your ordinary income for the year
- Pay the taxes — ideally from non-IRA funds; paying conversion taxes from the converted funds themselves reduces the amount that reaches your Roth
- Funds begin growing tax-free — from that point, the money in the Roth IRA grows and can be withdrawn tax-free after age 59½ (with a 5-year holding period)
The Tax Cost of Converting
Converting $50,000 from a traditional IRA when you're in the 22% federal tax bracket would generate roughly $11,000 in additional federal taxes. State income taxes may apply as well. The math gets more complex if the conversion pushes you into a higher bracket.
Example: Partial conversion to fill a bracket
If your taxable income is $75,000 and the 22% bracket ends at $100,525 (for single filers in 2024), you could convert up to ~$25,500 without moving into the 24% bracket. This "bracket-filling" approach is a common tax planning technique.
Roth Conversion vs. Backdoor Roth IRA
| Roth Conversion | Backdoor Roth IRA | |
|---|---|---|
| Who it's for | Anyone with existing pre-tax retirement funds | High earners exceeding direct contribution limits |
| Tax treatment | Pay taxes on amount converted | Pay taxes on non-deductible contribution (usually small) |
| Amount | As much as you want (no annual limit) | Limited to $7,000/year ($8,000 if 50+) |
| Timing | Anytime | Annual contribution cycle |
The Pro-Rata Rule
If you hold both pre-tax and after-tax money across all your traditional IRAs, conversions are not treated as coming purely from after-tax money. The IRS pro-rata rule requires that each conversion be treated as a proportional mix of pre-tax and after-tax funds, making partial conversions more complicated to execute cleanly.
5-Year Rule for Conversions
Each Roth IRA conversion has its own 5-year clock. Converted funds withdrawn before 5 years are subject to a 10% early withdrawal penalty on the conversion amount (not the earnings), even if you're over 59½. This is separate from the 5-year rule on Roth IRA earnings.
When a Roth Conversion May Not Make Sense
- You're in your peak earning years and face a high marginal rate today
- You plan to donate your IRA to charity (which eliminates the tax burden)
- You'll need the converted funds within a few years (5-year rule applies)
- You can't afford the tax bill without depleting the IRA itself
Consulting a fee-only financial advisor or CPA before executing a large conversion is strongly recommended.