A backdoor Roth is a two-step move for people whose income is too high to contribute to a Roth IRA directly. You contribute to a traditional IRA without taking a deduction, then convert that IRA to a Roth. Because there is no income limit on conversions, the money ends up in a Roth. It works cleanly only if you have no other pre-tax IRA money, because of a rule called the pro-rata rule.
Why would anyone need a backdoor?
Direct Roth IRA contributions phase out at higher incomes. For 2026, the phase-out runs from $153,000 to $168,000 of modified adjusted gross income for single filers, and from $242,000 to $252,000 for married couples filing jointly (IRS, Notice 2025-67, November 2025). Above the top of the range, you cannot contribute directly.
Conversions, though, have had no income limit since 2010. Anyone can contribute to a traditional IRA, deductible or not, as long as they or their spouse have earned income. Put those two rules together and you have the backdoor. Congress has discussed closing it more than once. IRS Publication 590-A, for 2025 returns, still describes conversions with no income test.
How much can go in for 2026?
The IRA contribution limit for 2026 is $7,500, plus a $1,100 catch-up for people 50 and over (IRS, November 2025). A married couple can each do their own, using the earned income of either spouse.
The steps
Check for other pre-tax IRA money
Look at every traditional, SEP and SIMPLE IRA in your name. Their combined balance on December 31 of the year you convert decides how the conversion is taxed. More on this below.
Contribute to a traditional IRA
Make a nondeductible contribution up to the annual limit. You can make it for the current year, or for the prior year up to the tax filing deadline in April.
Convert to a Roth IRA
Move the money from the traditional IRA to a Roth IRA. Many people convert soon after the contribution settles, so there is little or no growth to be taxed. Any growth before the conversion is taxable.
Report it on Form 8606
File IRS Form 8606 with your return. It records the nondeductible contribution, which creates your basis, and the conversion. Skip it, and the IRS may treat the whole conversion as taxable.
What is the pro-rata rule?
When you convert, the IRS does not let you choose to convert only the after-tax dollars. It treats all your traditional, SEP and SIMPLE IRAs as one pool. The share of the conversion that is tax-free equals your after-tax basis divided by the total balance of the pool on December 31 of the conversion year.
The IRS looks at every IRA you own, not just the one you used for the backdoor.
Hypothetical. Someone has $92,500 in an old rollover IRA, all pre-tax, and makes a $7,500 nondeductible contribution to a new IRA, then converts that $7,500. The pool is $100,000, and only $7,500 of it is basis. So only 7.5% of the conversion is tax-free. The other 92.5% is taxable, even though the money converted came from the after-tax contribution.
How do people deal with the pro-rata rule?
The common approach is to move pre-tax IRA money into an employer plan, such as a 401(k), if the plan accepts roll-ins. Money in a 401(k) does not count in the IRA pool. Because the pool is measured on December 31, the roll-in has to happen by the end of the year of the conversion. Not every plan accepts roll-ins, and moving money into a plan changes your investment options and fees, so it is a trade-off to weigh.
Note that the rule applies per person. A spouse's IRA does not count toward yours.
Is there a waiting period between the steps?
The tax code does not set one. Some people wait a short time between contribution and conversion. What matters more is that the records are clean and Form 8606 is filed every year you have basis.
What about the mega backdoor Roth?
A different move with a similar name. Some 401(k) plans allow after-tax contributions beyond the regular deferral limit, up to the $72,000 total annual additions limit for 2026, and then allow those to be converted to Roth inside the plan or rolled to a Roth IRA. Whether it is available depends entirely on your plan's terms.
How does Utah treat a backdoor Roth?
Utah's income tax starts from federal adjusted gross income, so any taxable part of a conversion is taxed in Utah at the flat individual rate. A clean backdoor Roth, with no pre-tax IRA money and no growth before conversion, adds little or nothing to federal or Utah income.
A backdoor Roth is one tool. Larger Roth conversions in low-income years are a separate strategy, covered in the Roth conversion window. Both work best when someone looks at the whole return, which is what our CPA-led tax planning is built to do.
Educational only. Not investment, tax, or legal advice. Every situation is different; the right answer depends on the numbers, and that's what the strategy session is for. Investing involves risk, including possible loss of principal.