SwitchWizeSmart financial decisions
P2

Backdoor Roth Calculator

Estimate how the IRA pro-rata rule may divide a Roth conversion between taxable pre-tax dollars and nondeductible basis.

Quick answer: Estimate the taxable share of a Roth conversion under a simplified pro-rata scenario using the user-entered pre-tax IRA balance and nondeductible basis. Enter Total Nondeductible IRA Basis, Amount You Plan to Convert, Existing Pre-Tax IRA Balance, and Marginal Tax Rate to personalize the estimate. It returns Taxable Portion of the Conversion, Pro-Rata Taxable Percentage, and Estimated Federal Tax on Taxable Portion so you can compare the impact before choosing a next step. Use it to compare long-term value, tax impact, risk, time horizon, and contribution choices.

Taxable Portion of the Conversion
$6,522
Taxable Portion of the Conversion
$6,522
Pro-Rata Taxable Percentage
86.96%
Estimated Federal Tax on Taxable Portion
$1,565
Diagnostic

Because of the pro-rata rule, about 86.96% of your conversion — $6,522 — is taxable.

At the entered marginal rate, the estimated federal tax attributable to that taxable portion is $1,565.

Compare IRA providers
What to do next

Compare IRA providers ->

Your action plan
  1. 1

    Set the target and timeline for this plan

    Estimate the taxable share of a Roth conversion under a simplified pro-rata scenario using the user-entered pre-tax IRA balance and nondeductible basis.

  2. 2

    Check the assumptions before using the result for a high-stakes decision

    Assumptions change the answer, especially when rates, taxes, or timing matter.

  3. 3

    Save the result to Money Map or use the linked next action

    Turn the result into a prioritized action instead of treating it as a one-off number.

Compare IRA providers

This is an educational estimate, not tax, legal, investment, or lending advice. Tax rules, rates, and eligibility change and depend on your full situation. Confirm with a qualified professional or the provider before acting.

Calculator action path

Turn this result into a decision

Every SwitchWize calculator connects to a product comparison, rate context, guidance, alerts, and Money Map.

Rate authority hub
Compare
You could gain ~$6,522/yr — compare nowMove from calculation to current product options.
Rate Trend
Track fed fundsUse market context before you decide when to act.
Guide
You Set Your 401(k) Contribution in January. That Doesn't Mean You're On Pace.Most people who mean to max out a 401(k), HSA, or IRA set a contribution percentage once and assume it's handled. A July pace check catches the gap while there's still time to fix it.
Money Map
Map this $6,522/yr opportunitySave this opportunity and see how it fits your broader money plan.
Alert
Create a rate alertWatch the market instead of checking manually.
Free to embed

Add this calculator to your site

Paste this snippet into any page. No account or API key required, the widget is responsive, and it updates with live rates. A SwitchWize attribution link is included in the embed automatically.

<iframe src="https://www.switchwize.com/embed/backdoor-roth" width="100%" height="680" loading="lazy" style="border:1px solid #e2e8f0;border-radius:14px;max-width:100%;width:100%" title="SwitchWize calculator"></iframe>
<script>(function(){window.addEventListener("message",function(e){if(e.origin!=="https://www.switchwize.com")return;var d=e.data;if(!d||d.type!=="sw-embed-resize")return;var f=document.getElementsByTagName("iframe");for(var i=0;i<f.length;i++){if(f[i].contentWindow===e.source){f[i].style.height=d.height+"px";break;}}});})();</script>

Frequently Asked Questions

Everything you need to know.

What does the Backdoor Roth Calculator show?
Estimate how the IRA pro-rata rule may divide a Roth conversion between taxable pre-tax dollars and nondeductible basis.
How should I use the result?
Use the result as a planning and comparison aid. Review the assumptions, adjust your inputs, and compare the output with your actual options before acting.
What should I do after using this calculator?
Use the related links and next-action modules on the page to compare products, continue in Money Map, or review related guidance on SwitchWize.
Is the Backdoor Roth Calculator free to use?
Yes. SwitchWize calculators are free, and you do not need an account to run scenarios or view the result.
Does using the Backdoor Roth Calculator affect my credit score?
No. Using a calculator does not trigger a credit check. A credit impact can occur only if you apply directly with a lender, card issuer, or provider.
Are the results personalized financial advice?
No. Calculator outputs are educational estimates based on the inputs you enter. Review assumptions and confirm terms directly with providers before making a financial decision.
What should I do after seeing the result?
Use the recommendation module on this page to compare ira providers ->, or run Money Map to compare this investing & retirement decision with your other opportunities.
How does SwitchWize choose related offers?
Related offers are matched by the calculator surface (ira) and ranked using SwitchWize data such as rate, fees, trust signals, product fit, and switching friction. Paid relationships do not change organic ranking order.
How fresh are the rates and offers shown?
Rate and offer data is reviewed on a recurring cadence and every offer module shows review context or links to the methodology and disclosure pages.
Where can I see the ranking methodology?
The SwitchWize methodology page explains how rate freshness, editorial review, affiliate disclosure, and category ranking factors work.
Can Money Map use this result?
Yes. Money Map is the broader diagnostic path: it compares savings, mortgage, cards, and debt so you can see whether this calculator result is your highest-impact next move.

Why This Matters

Backdoor Roth Calculator helps users make a investing & retirement decision with clearer numbers, assumptions, and next actions.

How to Use It

  1. 1Enter your numbers in the input panel.
  2. 2Review the live results and interpretation on the right.
  3. 3Use the goal outputs to compare options or plan the next step.
  4. 4Use the related links below if you want to move from analysis to action.
Related calculators
Roth IRA CalculatorRoth vs Traditional IRA CalculatorRoth Conversion Calculator with IRMAA Cliff — 2026
Compare IRA providers ->