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What Is a Backdoor Roth IRA?
A backdoor Roth IRA is a perfectly legal two-step strategy that lets high earners get money into a Roth IRA even when their income exceeds the IRS limits for direct Roth contributions. You make a nondeductible contribution to a traditional IRA (up to $7,000 in 2024 ($8,000 with catch-up)) and immediately convert it to a Roth IRA. Because the contribution was after-tax dollars, the conversion is largely tax-free, assuming you have no other pre-tax IRA balances. The backdoor Roth IRA calculator at the top of this page walks you through the math so you can see exactly how the strategy plays out in your situation.
The backdoor Roth IRA exists because Congress placed income limits on direct Roth IRA contributions but did not place income limits on Roth conversions. The Tax Increase Prevention and Reconciliation Act of 2005 removed the income cap on Roth conversions starting in 2010, opening a permanent door for high earners. Once dollars are inside the Roth, they grow tax-free and come out tax-free in retirement, with no required minimum distributions during your lifetime. Combined with our Roth IRA calculator and Roth conversion calculator, the backdoor Roth IRA gives you a complete tax-advantaged retirement toolkit.
Who Needs a Backdoor Roth IRA, 2024 Income Limits
You need the backdoor Roth IRA only if your Modified Adjusted Gross Income exceeds the IRS phase-out range for direct Roth IRA contributions. For 2024, single filers begin to phase out at $146,000 of MAGI and are completely shut out at $161,000. Married filing jointly phases out from $230,000 to $240,000. If your income falls below the floor of these ranges, contribute directly to a Roth IRA. There is no reason to use the backdoor route. If your income lands inside the phase-out range, you can make a partial direct contribution plus a partial backdoor contribution. According to IRS Publication 590-A, these limits are adjusted annually for inflation.
High earners are most likely to benefit from the backdoor Roth IRA calculator because their marginal tax rate today often differs significantly from their retirement tax rate, making the Roth treatment more valuable. Two-physician households, tech employees with large stock compensation, and small business owners frequently land well above the MAGI ceiling and rely on the backdoor route for any Roth contribution. The strategy also stacks with the mega backdoor Roth, see our mega backdoor Roth calculator for the after-tax 401(k) version that can move tens of thousands more dollars per year into Roth status.
The Pro-Rata Rule Explained
The single most important concept in the backdoor Roth IRA is the IRS pro-rata rule, codified in Internal Revenue Code Section 408(d). When you convert any traditional IRA dollars to a Roth, the IRS treats the conversion as a proportional slice of your aggregate IRA balance. If 90% of your aggregate IRA dollars are pre-tax and 10% are after-tax basis, then 90% of any conversion is taxable as ordinary income. The rule aggregates all your traditional, SEP, and SIMPLE IRAs across every provider, measured on December 31 of the conversion year. It does not look at individual accounts, so you cannot isolate the nondeductible contribution into a separate IRA to avoid the rule.
A concrete example clarifies the math. Suppose you have $93,000 of pre-tax IRA money from an old 401(k) rollover and you make a $7,000 nondeductible contribution to a traditional IRA. Your aggregate balance is $100,000, of which 7% is after-tax basis. If you convert $7,000 to Roth, only 7% of that ($490) is tax-free; the remaining $6,510 is taxed as ordinary income. At a 32% marginal rate, that creates a $2,083 tax bill on what you thought was a clean backdoor conversion. Investopedia walks through several similar scenarios. The fix is to move pre-tax IRA dollars into a current employer 401(k) before December 31, which makes future backdoor conversions essentially tax-free.
The backdoor Roth IRA calculator above runs the pro-rata calculation automatically and surfaces a warning whenever your pre-tax IRA balance creates a material tax bill. The result tells you the dollar tax cost of converting under the current configuration and how that changes your net contribution to the Roth.
Step-by-Step Backdoor Roth Process for 2024
The backdoor Roth IRA process is straightforward once you understand the moving parts. Step one: confirm your Modified AGI puts you above the direct Roth phase-out. The calculator above does this automatically based on your income input. Step two: open a traditional IRA at the same custodian where you hold or want to hold your Roth IRA. Most major brokerages (Fidelity, Vanguard, Schwab) support the workflow and many have a one-click conversion button.
Step three: contribute up to $7,000 (or $8,000 if 50 or older) as a nondeductible contribution to the traditional IRA. Do not take a deduction on your tax return, the whole point is that this is after-tax money. Step four: convert the traditional IRA balance to your Roth IRA. Most custodians let you do this online in seconds; convert within a few days of the contribution to minimize taxable earnings. Step five: file IRS Form 8606 with your tax return for the contribution year, and again the following year to report the conversion. The Bogleheads wiki maintains a detailed step-by-step guide with screenshots from each major custodian.
Spouses can each run their own backdoor Roth independently, doubling the family contribution to $14,000 (or $16,000 with catch-up). The pro-rata rule applies per person, not per couple, so each spouse evaluates their own IRA balances separately. For a spouse without earned income, use a spousal IRA contribution, see our Roth vs. traditional IRA calculator for a comparison of the two account types.
Common Backdoor Roth IRA Mistakes
The most common backdoor Roth IRA mistake is forgetting that the pro-rata rule aggregates every traditional, SEP, and SIMPLE IRA you own. Savers sometimes assume that opening a brand-new traditional IRA for the nondeductible contribution isolates it from a separate pre-tax IRA. It does not. The IRS sees all your IRAs as a single pool on December 31. If you have a six-figure rollover IRA from an old 401(k), the backdoor conversion will trigger a large tax bill unless you first roll that balance into your current employer plan.
The second-most common mistake is failing to file IRS Form 8606. Form 8606 establishes your basis (after-tax contributions) in the traditional IRA. Without it, the IRS has no record that the contribution was nondeductible and will tax the full conversion as ordinary income. File the form for the contribution year and again for the conversion year. Other errors include accidentally exceeding the annual contribution limit (combined across all your traditional and Roth IRAs), letting too much time pass between contribution and conversion (creating taxable earnings), and converting in the wrong tax year. The backdoor Roth IRA calculator above flags pro-rata risk and surfaces a recommendation tailored to your inputs.
For a complete retirement plan that incorporates the backdoor Roth alongside 401(k), Social Security, and pension strategies, explore our full set of retirement planners. The cluster works together to give you a coherent, optimized retirement strategy that balances tax diversification across pre-tax, Roth, and taxable buckets.