How to Do a Backdoor Roth IRA Conversion

What a backdoor Roth conversion is and why you might use it

A backdoor Roth conversion is a way to move money into a Roth IRA when your income is too high to contribute directly. The IRS does not allow direct contributions to a Roth if your modified adjusted gross income (MAGI) exceeds certain thresholds — those limits change yearly and depend on your filing status. A backdoor conversion gets around this by using a traditional IRA as an intermediate step.

Here is how it works in plain terms: you put after-tax money into a traditional IRA, then convert that money to a Roth IRA. The conversion itself has no income limit. Once the money is in the Roth, it grows tax-free and you can withdraw it tax-free in retirement, just like a regular Roth contribution would.

This strategy is most useful if you earn above the Roth contribution limit but want to save in a Roth account. It is also common for people who have received a large bonus, inheritance, or other windfall and want to move that money into tax-advantaged retirement savings.

Key Takeaways

• A backdoor Roth involves depositing after-tax money into a traditional IRA, then converting it to a Roth IRA in the same tax year.
• You must report the conversion on Form 8606 when you file your taxes, and you will owe income tax on any pre-tax money in your traditional IRAs at the time of conversion.
• The IRS "pro-rata rule" means if you have other traditional IRAs with pre-tax balances, part of your conversion will be taxable — you cannot convert only the after-tax portion.
• The entire process takes one to three weeks if your IRA provider processes transfers quickly, but you should complete it within the same calendar year.
• A backdoor Roth is legal and common, but the steps must be done in the correct order and documented carefully to avoid IRS penalties.

Step-by-step process for a backdoor Roth conversion

The conversion happens in two parts: the deposit and the conversion. First, deposit after-tax money into a traditional IRA at your bank or brokerage. This is a regular deposit — you are not claiming a tax deduction for it. Write down the exact amount and the date.

Second, once the money has settled (usually one to three business days), contact your IRA provider and ask them to convert the traditional IRA to a Roth IRA. Some providers let you do this online; others require a phone call or a form. The provider will move the money from the traditional IRA to your Roth IRA. This is the conversion step.

Do not wait months between the deposit and the conversion. The longer the money sits in the traditional IRA, the more it can earn interest or investment gains, and those gains become taxable when you convert. Most people complete both steps within a few days of each other.

Keep records of the deposit: a bank statement, a confirmation email, or a screenshot showing the date and amount. You will need this when you file taxes.

Understanding the pro-rata rule and pre-tax IRA balances

The pro-rata rule is the most important thing to understand before you start. If you have any traditional IRAs, SEP IRAs, or straightforward IRAs with pre-tax money in them, the IRS treats all your IRAs as one pool when you convert. You cannot convert only the after-tax portion and leave the pre-tax portion behind.

Here is an example: suppose you have a traditional IRA with $10,000 in pre-tax contributions (money you deducted when you contributed it). You then deposit $5,000 in after-tax money and convert it. The IRS sees $15,000 total: $10,000 pre-tax and $5,000 after-tax. When you convert the $5,000, the pro-rata rule says 67% of it ($3,333) is treated as pre-tax money and 33% ($1,667) is treated as after-tax money. You owe income tax on the $3,333 portion.

If you have no other traditional IRAs, the pro-rata rule does not explore — all your money is after-tax and the conversion is tax-free. If you do have other traditional IRAs, you have two options: roll those IRAs into a workplace 401(k) plan (if your employer allows it) before you convert, or accept that part of your conversion will be taxable.

Reporting the conversion on your tax return

You must report the conversion on Form 8606 when you file your tax return for the year you converted. Your IRA provider will send you a Form 1099-R showing the conversion amount. The 1099-R goes to the IRS automatically, so if you do not file Form 8606, the IRS will likely notice the mismatch.

Form 8606 asks you to report the total value of all your traditional, SEP, and straightforward IRAs on December 31 of the conversion year, the amount you converted, and how much of that amount was pre-tax versus after-tax. If you converted after-tax money only and have no other IRAs, most of the form is straightforward. If the pro-rata rule applies, the calculation is more complex — you may want to work with a tax professional.

You file Form 8606 with your regular tax return (Form 1040). If you owe tax on the conversion, you pay it when you file. If you do not file Form 8606 and the IRS catches the conversion, you can face penalties and interest.

Timing and tax-year rules

You must complete the entire backdoor Roth process — deposit and conversion — within the same calendar year. If you deposit in December 2024 and convert in January 2025, the IRS treats it as a 2025 conversion, not a 2024 one. This matters because you can only do one backdoor Roth per person per year.

The "per year" rule means you and your spouse can each do a backdoor Roth in the same year, but you cannot do two backdoor Roths yourself in one year. If you try, the second one is treated as an excess contribution and you will owe a 6% penalty tax each year the excess sits in the Roth until you remove it.

File Form 8606 by the tax-filing important date for that year (usually April 15 of the following year, or October 15 if you file an extension). If you miss the important date, you can still file Form 8606 late, but the IRS may assess penalties. It is better to file on time.

Common mistakes to avoid

The most common mistake is not checking for other traditional IRAs before you convert. If you have an old 401(k) that you rolled into a traditional IRA years ago and forgot about, the pro-rata rule will catch you. Before you start, log into every financial institution where you have ever had an IRA and confirm the balance.

Another mistake is waiting too long between the deposit and the conversion. If the after-tax money earns interest or investment gains while it sits in the traditional IRA, those gains are taxable when you convert. Deposit and convert within a few days.

A third mistake is not keeping records. Your IRA provider will send you a 1099-R, but you should also keep your own copies of the deposit confirmation and the conversion confirmation. If the IRS ever questions the conversion, these records prove you did it correctly.

Finally, some people try to do a backdoor Roth and then when ready withdraw the money from the Roth. This does not work. If you withdraw within five years of opening the Roth, you owe a 10% early-withdrawal penalty on the earnings (though not on the after-tax contributions themselves). The backdoor Roth is meant to be a long-term move.

Working with your bank or brokerage

Not all IRA providers make the backdoor Roth process straightforward. Some have online forms; others require a phone call. A few charge a small fee to process the conversion. Before you start, call your IRA provider and ask them what steps you need to take.

Tell them you want to deposit after-tax money into a traditional IRA and then convert it to a Roth IRA. They should be familiar with this — it is a standard request. Ask them how long each step takes and whether they have a form you need to sign. Some providers let you do the conversion when ready after the deposit; others require the money to settle first.

If your provider makes the process difficult or charges a high fee, consider moving your IRA to a larger brokerage like Fidelity, Vanguard, or Charles Schwab. These firms process backdoor Roths routinely and usually do not charge.

Frequently Asked Questions

Can I do a backdoor Roth if I have a 401(k) at work?

Yes. A 401(k) does not count toward the pro-rata rule — only traditional IRAs, SEP IRAs, and straightforward IRAs do. If you have a 401(k) and no traditional IRA, you can do a backdoor Roth without any tax consequence. If you do have a traditional IRA, you can roll it into your 401(k) first (if your plan allows it), then do the backdoor Roth.

What if I convert and then realize I made a mistake?

You can undo a conversion by doing a "recharacterization" — moving the money back from the Roth to the traditional IRA. You must do this before you file your tax return for that year. After you file, you cannot recharacterize. If you realize the mistake after filing, you would need to file an amended return and ask the IRS to reverse the conversion, which is more complicated.

Do I owe taxes on the conversion?

Only if you have pre-tax money in other traditional IRAs. If all your IRA money is after-tax, the conversion is tax-free. If you have pre-tax IRAs, the pro-rata rule applies and part of the conversion is taxable. You owe income tax on the taxable portion when you file your return.

Can my spouse do a backdoor Roth in the same year?

Yes. Each person can do one backdoor Roth per calendar year. If you are married and both want to do a backdoor Roth, you each deposit into your own traditional IRA and convert to your own Roth IRA. You each file Form 8606 on your joint tax return.

What happens if I withdraw from the Roth after converting?

If you withdraw within five years of opening the Roth, you owe a 10% early-withdrawal penalty on any earnings. You can withdraw the after-tax contributions you converted without penalty, but the earnings are penalized. This is why the backdoor Roth works best as a long-term strategy — the money should stay in the Roth until retirement.