Backdoor Roth IRA Calculator for High Earners

If your income is too high to contribute to a Roth IRA directly, you can still get money into one through the "backdoor": contribute to a traditional IRA without taking a deduction, then convert it to a Roth.

For 2026, a backdoor Roth lets you move $7,500 ($8,600 if you're 50 or older) into a Roth IRA regardless of income. It's essentially tax-free if you have no other pre-tax money in traditional, SEP, or SIMPLE IRAs on December 31 of the conversion year. If you do, the pro-rata rule makes part of the conversion taxable. This calculator estimates that tax and the long-term value of doing it every year.

This calculator is for informational purposes only. Results are estimates based on the rates and balances you enter and may differ from your actual tax.

Who needs the backdoor?

You can't contribute directly to a Roth IRA once your modified AGI reaches the top of the phase-out range. For 2026, per the IRS 2026 limits announcement:

Between those numbers you can make a reduced direct contribution and use the backdoor for the rest. Not sure of your MAGI? The MAGI calculator walks through the add-backs.

If you already made a direct Roth contribution above your limit, a later backdoor doesn't fix it. Use the excess Roth IRA contribution calculator to size the correction, and follow the deadlines and steps in how to fix an excess Roth IRA contribution.

What each input means

How the calculator does the math

Pro-rata taxable amount:

Taxable part of conversion = Contribution × Existing pre-tax IRA balance ÷ (Existing balance + Contribution)

Tax on the conversion: Taxable part × current tax bracket.

Future value of yearly backdoor contributions (an ordinary annuity):

FV = Contribution × [(1 + r)^years − 1] ÷ r

Tax savings versus leaving the money in a traditional IRA: (FV − total contributions) × expected retirement tax rate. Someone above the Roth limit who skips the conversion still has nondeductible contributions in a traditional IRA. Those contributions are basis and come back tax-free, so only the earnings would be taxed at withdrawal. The Roth makes those earnings tax-free, and that is the whole saving. (The comparison is not against a deductible IRA or 401(k), because a backdoor contribution never gave you a deduction to begin with.)

The real IRS calculation on Form 8606 uses your traditional, SEP, and SIMPLE IRA values as of December 31 of the conversion year, plus any conversions and distributions during the year. Enter the balance you expect on that date, not today's.

Worked example: the default inputs

A single filer earns $180,000 (above the $168,000 ceiling), contributes $7,500 a year, has no other IRA money, expects an 8% return, and plans 30 more years of contributions.

• Taxable part of each conversion: $0 (no pre-tax IRA balance)
• Total contributed over 30 years: $7,500 × 30 = $225,000
• Future value: $7,500 × (1.08³⁰ − 1) ÷ 0.08 ≈ $849,624
• Growth: about $624,624, all of it tax-free if withdrawals are qualified
• Left unconverted in a traditional IRA, the $225,000 of contributions would come out tax-free but the $624,624 of earnings would be taxed; at a 24% retirement rate that is about $149,910 of federal income tax the Roth avoids

Those figures assume the contribution limit stays at $7,500. In practice it is indexed for inflation, so the real result could be higher.

How the pro-rata rule changes the tax

Now suppose the same filer has an old rollover IRA. Here is the tax on converting a $7,500 nondeductible contribution at a 32% bracket:

With a $92,500 rollover IRA, 92.5% of each "backdoor" conversion is taxable, and the unconverted after-tax basis stays trapped in the traditional IRA until you convert or withdraw everything. That's why cleaning up pre-tax IRA balances comes first.

Ways to clear pre-tax IRA balances

• Roll pre-tax IRA money into your current 401(k) or 403(b) if the plan accepts roll-ins. Employer plan balances don't count in the pro-rata math. Complete it by December 31 of the year you convert.
• Convert the whole pre-tax balance in one year, paying the tax, so future backdoors are clean. The Roth conversion calculator shows what that would cost in your bracket.
• Use a solo 401(k) if you have self-employment income; it can accept IRA roll-ins. See the solo 401(k) calculator.

Step by step: doing the backdoor correctly

1. Check the December 31 picture. Total your traditional, SEP, and SIMPLE IRA balances you'll have at year-end. If it isn't zero, decide how to clear it.
2. Open a traditional IRA and a Roth IRA at the same brokerage to make the conversion a simple internal transfer.
3. Contribute up to $7,500 ($8,600 at 50+) to the traditional IRA and don't deduct it. For 2026, you have until April 15, 2027.
4. Leave it in cash or a money market fund until it settles, so little or no earnings build up.
5. Convert the full balance to the Roth IRA. Any interest earned before conversion is taxable, usually a few dollars.
6. Choose no tax withholding on the conversion.
7. File Form 8606 with your return. In Part I, report the nondeductible contribution (line 1) and your prior basis (line 2), and enter your December 31 traditional IRA value (line 6). In Part II, report the amount converted (line 16) and the nontaxable basis (line 17); line 18 is the taxable amount that flows to Form 1040 line 4b. See About Form 8606.
8. Keep the forms: Form 5498 from the custodian showing the contribution, and Form 1099-R showing the conversion.

Married couples and the backdoor

Each spouse can do a backdoor Roth, so a couple can move $15,000 a year in 2026 ($17,200 if both are 50+). The non-working spouse can contribute based on the working spouse's earned income if you file jointly. The pro-rata rule is figured per person: your spouse's rollover IRA doesn't make your conversion taxable, and each of you files your own Form 8606.

The mega backdoor Roth

Some 401(k) plans allow after-tax (non-Roth) contributions beyond the $24,500 employee deferral limit, plus in-plan Roth conversions or in-service withdrawals of that money. Total additions to a defined contribution plan, employee plus employer, can reach $72,000 for 2026 under IRS Notice 2025-67, not counting catch-up contributions.

Example: you defer $24,500 and your employer adds $10,000. Your after-tax room is $72,000 − $24,500 − $10,000 = $37,500, which can then be converted to Roth. Only the earnings between contribution and conversion are taxable. This is a plan feature, not an IRA strategy, so check your plan document first.

Common backdoor Roth mistakes

• Ignoring old IRAs. SEP and SIMPLE IRAs count toward the pro-rata rule, not just traditional IRAs.
• Rolling an old 401(k) into an IRA in the same year. That rollover lands in your December 31 balance and makes your conversion mostly taxable. See the trade-offs in the 401(k) rollover calculator.
• Deducting the contribution. If you or your spouse are covered by a workplace plan and your income is above the deduction phase-out ($81,000–$91,000 single, $129,000–$149,000 joint for 2026), you can't deduct it anyway, and claiming the deduction undoes the backdoor.
• Skipping Form 8606. Without it, the IRS has no record of your after-tax basis, and you could pay tax twice. The form carries a $50 penalty for failing to file it when required.
• Withdrawing converted money too soon. If you're under 59½, each conversion has a five-year clock before converted dollars come out penalty-free. The full timing rules are explained in how to roll a 401(k) into a Roth IRA without a penalty.

Is the backdoor worth it?

It almost always is for high earners who already max out workplace plans and have no pre-tax IRA balances. The tax cost is near zero, and the payoff is tax-free growth with no lifetime required minimum distributions. It is less compelling if you have a large rollover IRA that you can't move into a workplace plan, because the pro-rata tax can approach the cost of a full conversion.