Roth Conversion
A Roth conversion is the process of moving funds from a Traditional IRA, 401(k), or other pre-tax retirement account into a Roth IRA, triggering income tax on the converted amount in exchange for future tax-free growth and withdrawals.
A Roth conversion is a deliberate tax strategy: you pay income tax today on pre-tax retirement dollars in exchange for permanently removing those assets — and all future growth — from the reach of the IRS. The converted amount is added to your taxable income in the year of conversion, taxed at ordinary income rates, and then treated as Roth dollars going forward.
There is no limit on the amount you can convert in a single year, and there are no income restrictions on conversions (unlike direct Roth IRA contributions). This open-door policy is what makes the backdoor Roth IRA strategy possible. However, large conversions can push you into a higher marginal tax bracket, trigger the Net Investment Income Tax (3.8% on investment income above certain thresholds), increase Medicare premiums through IRMAA surcharges with a two-year look-back, or reduce the tax efficiency of itemized deductions.
The ideal time to execute a Roth conversion is during a 'tax valley' — a year in which your income is temporarily lower than usual. Common windows include the years between retirement and Social Security claiming, years with large itemized deductions or business losses, years of reduced employment income, or early retirement years before RMDs begin. For retirees in their 60s, the window between retiring and turning 73 (when RMDs start) is often the prime Roth conversion opportunity.
Partial conversions are perfectly legal and often the smartest approach: convert only enough each year to fill up your current tax bracket without spilling into the next. A financial planner or CPA can model the optimal conversion amount using software that accounts for Social Security taxation, Medicare surcharges, and long-term bracket projections.
After a Roth conversion, the five-year Roth conversion clock starts fresh for each converted amount — you must wait five years from the conversion date (or reach 59½) to withdraw the converted principal penalty-free. This is separate from the five-year rule for Roth contributions. Once inside a Roth IRA, the converted funds compound tax-free indefinitely, with no RMDs during the owner's lifetime.