Backdoor Roth Calculator
Calculate your pro-rata tax liability and model the 20-year tax-free growth advantage of a Backdoor Roth IRA.
2026 IRS Rules & Limits
- Contribution Limit: $7,500 (or $8,600 if you are age 50 or older).
- Income Phase-Outs: You cannot contribute directly to a Roth IRA if your Modified Adjusted Gross Income (MAGI) exceeds $242,000 - $252,000 (Married Filing Jointly) or $153,000 - $168,000 (Single).
- Because most attending physicians exceed these limits, the "Backdoor" method (making a non-deductible Traditional IRA contribution and immediately converting it) is necessary.
Calculator Inputs
Usually $7,500 or $8,600.
Total in Traditional, SEP, and SIMPLE IRAs across all your accounts.
Clear to Convert!
Since your pre-tax IRA balance is $0, your conversion will be 100% tax-free. You owe $0 in pro-rata taxes.
20-Year Growth Advantage
Assuming a one-time $7,500 contribution growing at 7% annually.
100% Tax-Free at withdrawal
Gains subject to 15% Long-Term Capital Gains Tax
Doing this backdoor strategy saves you $3,228 in future taxes on just this single year's contribution!
(sends these numbers to Ask; we don't keep them)
Clinical Context & Calculation Details
How to Use This Calculator
Use this calculator to determine your eligibility to safely perform a Backdoor Roth IRA conversion without facing unexpected tax bills.
Simply enter your existing pre-tax IRA balance and planned contribution. The tool will calculate any pro-rata tax liability and model the 20-year tax savings of using the Roth strategy over a taxable account.
Why Doctors Need This
Physicians typically earn too much to contribute directly to a Roth IRA. The Backdoor Roth is a legal loophole that allows high earners to still access tax-free retirement growth.
By contributing annually, you build a pool of tax-free money that won't increase your taxable income in retirement and isn't subject to Required Minimum Distributions (RMDs).
Pearls & Pitfalls
- Pearl: Always ensure your Traditional IRA balance is $0 on December 31st of the year you do the conversion to avoid the Pro-Rata rule.
- Pitfall: Forgetting to file IRS form 8606. This form proves to the IRS that your contribution was non-deductible. Without it, you might be taxed twice on the same money!
- Pitfall: Not realizing that SEP and SIMPLE IRAs also count towards the pro-rata calculation. Roll these into a 401(k) or 403(b) first if possible.
Worked Example
The calculator's default inputs: a $7,500 nondeductible IRA contribution converted to Roth, $0 in other pre-tax IRAs and a 35% tax rate.
| Step | Calculation | Result |
|---|---|---|
| Taxable share of the conversion | $0 pre-tax ÷ $7,500 total | 0.0% |
| Tax on the conversion | $0 taxable × 35% | $0 |
| Roth after 20 years | $7,500 × 1.07^20 | $29,023 |
| Taxable account after 20 years | $7,500 + $21,523 gain × (1 − 15%) | $25,794 |
| Roth advantage | $29,023 − $25,794 | $3,228 |
With a $100,000 rollover IRA. The taxable share becomes $100,000 ÷ $107,500 = 93.0%, so $6,977 of the $7,500 conversion is taxable and the tax is about $2,442. Rolling the pre-tax IRA into a 401(k) or 403(b) before December 31 removes it from the calculation.
Assumptions & Sources
- 2026 IRA limit: $7,500, or $8,600 at age 50 and over: IRS, IRA contribution limits.
- Pro-rata rule: the taxable share of a conversion is your pre-tax IRA money divided by all traditional, SEP and SIMPLE IRA money, measured on December 31 of the conversion year, with the nondeductible contribution as your only basis: IRS, Form 8606. 401(k) and 403(b) balances do not count.
- Tax rate is the one you enter, applied to the whole taxable amount. State tax is included only if you add it to the rate.
- Growth: 7% a year for 20 years on one contribution. The taxable account pays 15% long-term capital gains tax once at the end, with no tax on dividends along the way. Many physicians pay 20% plus the 3.8% net investment income tax, so the Roth advantage shown is conservative.
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About the Author
Joshua Dunigan, DO | Family Medicine Resident & Founder
I'm a family medicine resident physician in Des Moines, Iowa (class of 2027). I founded MedMoneyGuide to give physicians specialty-specific financial guidance, with sources you can check.