How can I avoid the pro-rata rule completely?

You can roll over your entire pre-tax Traditional, SEP, or SIMPLE IRA balance into an active employer 401(k) plan. 401(k) balances are completely excluded from IRS Form 8606 calculations.

Updated: August 2026 • Verified v1.2

Backdoor Roth IRA Tax & Pro-Rata Rule Calculator

Finance & MathPopular

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Tax_Free_Ratio = Basis / (Total_PreTax_IRA + Conversion); Taxable = Conversion * (1 - Tax_Free_Ratio); Tax_Due = Taxable * Bracket

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Understanding Your Results

Calculates the exact tax-free percentage, taxable conversion amount, tax liability based on marginal bracket, and flags whether the conversion is 100% clean or subject to the pro-rata penalty.

Practical Guidance & Next Steps

Rolling pre-tax traditional IRA balances into an employer 401(k) before December 31st eliminates the pro-rata tax completely.

What is this?

A wealth tax planning utility that models IRS Form 8606 pro-rata rules for Backdoor Roth conversions.

How does it work?

1. Enter conversion amount ($7,000) and existing pre-tax Traditional/SEP IRA balance. 2. Select your marginal tax bracket. 3. View tax-free ratio, taxable dollars, estimated tax bill, and strategy guidance.

Why use it?

Prevents surprise multi-thousand-dollar tax bills when high earners convert non-deductible IRA dollars.

Technical Scope & Calculation Limitations

Models IRS Form 8606 IRA basis and aggregation rules.

Frequently Asked Questions

The IRS pro-rata rule requires that any Roth IRA conversion draws proportionally from all of your existing Traditional, SEP, and SIMPLE IRAs combined. You cannot selectively convert only after-tax dollars if you hold pre-tax IRA funds.

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