Roth Conversion & Backdoor Roth Calculator
Estimate the tax cost of a standard Roth conversion with break-even analysis, or switch to Backdoor Roth mode for high-income earners to check eligibility, pro-rata impact, and multi-year accumulation.
Last updated: 2026-03-27
Roth conversion & backdoor Roth calculator
Enter your values
Estimate standard conversion tax cost, or plan a backdoor Roth strategy with pro-rata analysis and income limit checks.
Conversion Analysis
--
Choose Standard mode for a lump conversion analysis, or Backdoor mode for high-income Roth IRA planning with pro-rata impact.
Calculation History(0)
Example calculations
Tap an example to prefill the calculator with sample values.
Mid-career partial conversion
$50k conversion at a 24% federal bracket edge
Useful for seeing whether today's tax cost is low enough relative to a lower future retirement tax rate.
Result: A moderate upfront tax hit can still create a five-figure long-run after-tax edge if retirement tax rates stay lower
Backdoor Roth — clean (no pre-tax IRA)
High earner with $200K MAGI, no existing traditional IRA
The ideal backdoor scenario: no pre-tax IRA balance means the pro-rata rule has zero impact. The full contribution converts tax-free.
Result: $7,000 converts tax-free each year — $0 tax impact because there's no pre-tax IRA balance
Backdoor Roth — pro-rata trap
High earner with $50K in an old rollover IRA
The pro-rata rule makes most of each backdoor conversion taxable when pre-tax IRA funds exist. Consider rolling into a 401(k) first.
Result: With $50K pre-tax IRA, ~87% of each conversion is taxable — the pro-rata rule significantly reduces the backdoor benefit
How the Roth conversion estimate works
In Standard mode, the calculator computes the incremental federal tax created by stacking the conversion on top of your current taxable income, then adds a flat state-tax assumption for a clearer all-in conversion cost. It grows the converted amount forward and compares a tax-free Roth balance with an after-tax traditional balance.
In Backdoor mode, the calculator checks your MAGI against Roth income limits, applies the pro-rata rule using your total traditional IRA balance, and projects the annual accumulation from repeated backdoor contributions over multiple years.
This is a planning estimate, not tax advice. Roth IRA rules, income limits, and contribution caps change — consult a tax professional before executing a conversion strategy.
Roth conversion & backdoor FAQs
Tax brackets, pro-rata rule, income limits, and how to read the projected after-tax edge.
Why does the calculator ask for taxable income instead of gross income?
Because the incremental tax on a conversion depends on where the conversion lands inside the tax brackets after deductions. Taxable income gives a cleaner basis for that marginal-tax estimate.
What is the backdoor Roth IRA?
A backdoor Roth is a two-step strategy for high earners above the Roth IRA income limit: contribute after-tax money to a traditional IRA, then immediately convert it to a Roth. It is legal but subject to the pro-rata rule if you have existing pre-tax IRA funds.
What is the pro-rata rule?
The IRS treats all your traditional IRA funds as one pool. When you convert, the taxable portion is based on the ratio of pre-tax funds to total IRA funds — not just the specific dollars you contributed. If you have $50K pre-tax and contribute $7K after-tax, about 88% of a conversion is taxable.
How do I avoid the pro-rata rule?
Roll your pre-tax traditional IRA funds into an employer 401(k) before doing the backdoor conversion. This removes the pre-tax balance from the pro-rata calculation, making the backdoor contribution convert nearly tax-free.
Is the break-even result exact?
No. It is a simplified planning estimate based on the tax rate and growth assumptions you entered. Real outcomes depend on legislation, state moves, withdrawal timing, and how the conversion tax is actually funded.
Embed this calculator
Copy the code below to embed this calculator on your website or blog. It's free — no API key needed.
<iframe src="https://calc.mintloop.dev/embed/investing/roth-conversion-calculator" width="100%" height="600" frameborder="0" title="Roth Conversion & Backdoor Roth Calculator" loading="lazy"> </iframe>
Optional: auto-resize script
<script>
var CALC_HUB_ORIGIN = 'https://calc.mintloop.dev';
window.addEventListener('message', function(e) {
if (e.origin !== CALC_HUB_ORIGIN) return;
if (!e.data || e.data.type !== 'calc-hub-resize') return;
var frames = document.querySelectorAll('iframe[src*="calc.mintloop.dev"]');
frames.forEach(function(f) {
if (f.contentWindow === e.source) {
f.style.height = String(Math.max(0, Number(e.data.height) || 0)) + 'px';
}
});
});
</script> Related tools
Use nearby tax and retirement calculators to pressure-test the broader conversion plan.
Get more retirement and investing calculators
Join the Calc Hub newsletter for new calculators for portfolio planning, taxes, retirement decisions, and income strategy.
Join the Calc Hub newsletterWas this calculator helpful?
Your feedback helps us improve future calculators.