US Backdoor Roth IRA & Pro-Rata Rule Calculator
Model high-earner non-deductible IRA contributions, conversion taxes under IRS Form 8606 pro-rata aggregation, and 30-year tax-free growth.
Model high-earner non-deductible IRA contributions, conversion taxes under IRS Form 8606 pro-rata aggregation, and 30-year tax-free growth.
Model high-earner non-deductible IRA contributions, conversion taxes under IRS Form 8606 pro-rata aggregation, and 30-year tax-free growth. Calculate exact, penny-accurate projections compliant with 2026 IRS • St. Louis FED (FRED) standards using Calconova's deterministic IEEE-754 (Decimal.js) calculation engine with instant breakdowns.
Annual contribution, existing IRA balances, and tax brackets
2026 IRS Limit: $7,000 (under age 50) or $8,000 (catch-up age 50+)
Sum of all Traditional, SEP, and SIMPLE IRAs across all brokerages (exclude 401k/403b).
Because you have $25,000 in pre-tax IRAs, 78.1% of your Backdoor conversion is taxable, resulting in an immediate $1,750 tax bill.
Fix: Reverse-rollover your pre-tax IRA into an active employer 401(k) before Dec 31st to make this 100% tax-free!
Immediate tax bill due for current tax year
Tax-Free Conversion
$1,531.25
Taxable Conversion
$5,468.75
Tax-Free Ratio
21.9%
Total IRA Aggregation
$32,000
Estimated future tax-free withdrawal value (saving roughly $11,420.28 in retirement taxes).
Taxable Ratio = 1 - [ Non-Deductible Basis ÷ (Total Pre-Tax IRA Balances + Current Year Contribution) ]Taxes owed = Conversion Amount × Taxable Ratio × Marginal Tax Rate. The remaining tax-free basis stays in your traditional IRA or carries over to the Roth.
All calculations, amortizations, and scenario projections displayed on this page are strictly for informational and educational purposes. Nothing herein constitutes investment, financial, tax, underwriting, or legal advice. Actual interest rates, closing costs, lender fees, and statutory criteria may vary. Calconova explicitly disclaims all liability for any financial decisions or actions taken based upon these calculations. Users are strongly advised to consult a certified financial planner, CPA, or licensed lending officer prior to executing financial commitments.
The Backdoor Roth IRA is an IRS-sanctioned tax strategy for high-income earners whose Modified Adjusted Gross Income exceeds IRS Roth contribution thresholds ($161k for singles, $240k for MFJ). You make a non-deductible contribution to a traditional IRA and promptly convert it to a Roth IRA.
Under IRS Form 8606, you cannot convert only non-deductible dollars if you own existing pre-tax Traditional, SEP, or SIMPLE IRAs. The IRS aggregates all your IRA balances as of December 31, taxing your conversion proportionately. For example, if 80% of your total IRA assets are pre-tax, 80% of your conversion is taxable.
Roll over your existing pre-tax IRA balances into an active employer 401(k) or 403(b) plan before December 31st of the conversion year. Employer 401(k) plans are completely exempt from the IRS Form 8606 pro-rata aggregation rule, leaving your IRA balance at $0 and your Backdoor Roth 100% tax-free!
Project retirement savings with employer match, compound returns, and IRS annual contribution limits.
Calculate 2026 IRS tax brackets, standard deduction, Social Security, Medicare, and take-home pay.
Calculate combined state and municipal sales tax for all 50 US states.