Backdoor Roth IRA
A non-deductible traditional IRA contribution converted to Roth, which the income limits do not restrict.
Direct Roth contributions phase out above certain incomes, but conversions do not, and non-deductible traditional IRA contributions have no income limit at all. The two facts together produce the route: contribute without deducting, then convert. Since the contributed money was already taxed, only subsequent earnings are taxable at conversion.
The pro-rata rule is the complication that catches people. Conversions are treated as coming proportionally from all traditional, SEP and SIMPLE IRA balances combined, not from the specific dollars just contributed. Existing pre-tax balances therefore make part of any conversion taxable, calculated across the aggregate rather than per account.
The mega version uses after-tax contributions to a 401(k) above the elective deferral limit, converted in-plan to Roth. It depends entirely on whether the plan document permits after-tax contributions and in-plan conversions, and many do not. The combined 401(k) cap from all sources was $70,000 in 2025.
Worked through
The sequence
- 1
Non-deductible traditional IRA contribution
No income limit applies to this step
- 2
Convert to Roth
Earnings between the two steps are taxable
- 3
Pro-rata applies across all traditional IRAs
A zero pre-tax balance leaves nothing to prorate
See your own backdoor roth ira
Promi computes this from your linked accounts, with the definition one click from the number.
Try the demo