Free backdoor Roth IRA calculator from Fynvorax. Estimate tax impact, long-term growth, and pro-rata rule exposure for high-income savers.
Backdoor Roth: nondeductible traditional IRA contribution then convert to Roth when income limits block direct Roth IRA. Pro-rata rule can tax conversion if you have other pre-tax IRA balances.
This rule dictates that if you own pre-tax assets in any Traditional IRA, the IRS considers any backdoor conversion to consist of a blended percentage of pre-tax and after-tax funds, resulting in unexpected tax bills on the conversion.
IRS taxes Roth conversions proportionally across all traditional IRA balances. Large pre-tax IRA → mostly taxable conversion unless you roll pre-tax into a 401(k) first.
High earners above Roth IRA income limits with no large pre-tax IRA balances (or ability to isolate via 401k rollover).
Annually per tax year while rules allow — coordinate with tax filing and Form 8606 (U.S.).