How Roth Conversions Are Taxed and What You Owe

Yes, Roth conversions are taxable in the year you convert

When you move money from a traditional IRA or 401(k) to a Roth IRA, the IRS treats that transfer as income on your tax return for that year. You pay ordinary income tax on the amount you convert — the same tax rate as your regular wages or salary. The conversion itself does not happen tax-free; the tax bill arrives when you file your return the following spring.

The amount you owe depends on how much you convert and what portion of your IRA balance consists of pre-tax contributions versus after-tax contributions. If your entire traditional IRA holds only pre-tax money (the most common case), you pay tax on the full conversion amount. If you have already made after-tax contributions to a traditional IRA, the calculation becomes more complex, and you may owe tax on only part of what you convert.

Key Takeaways

You owe federal income tax on the full amount you convert from a traditional IRA to a Roth IRA, calculated at your ordinary income tax rate for that year.
The tax is due when you file your return the following year, not when you make the conversion.
If you have both pre-tax and after-tax money in traditional IRAs, the IRS requires you to calculate tax on a blended basis across all your IRAs combined, not just the one you convert from.
State income tax may also apply to the conversion amount, depending on where you live.
You can pay the tax from the conversion funds themselves, but doing so reduces the amount that ends up in your Roth account.

How the tax is calculated when you have only pre-tax contributions

If all the money in your traditional IRA came from deductible contributions or rollovers from a 401(k), the entire conversion amount is taxable. For example, if you convert $50,000, you add $50,000 to your taxable income for the year. At a 24% federal tax bracket, that means roughly $12,000 in federal tax owed.

The IRS sends you a Form 1099-R in January showing the conversion amount. You report this on your tax return, and the tax is calculated based on your total income for the year and your filing status. The conversion can push you into a higher tax bracket, which means you may pay a higher rate on the conversion amount than you would on regular income.

The pro-rata rule when you have both pre-tax and after-tax money

The complication arises if you have made non-deductible (after-tax) contributions to a traditional IRA. The IRS does not let you pick and choose which dollars to convert. Instead, it applies the pro-rata rule, which requires you to calculate tax based on the ratio of pre-tax to after-tax money across all your traditional IRAs combined, not just the one you convert from.

Here is the math: suppose you have $100,000 in traditional IRAs total — $80,000 pre-tax and $20,000 after-tax. If you convert $50,000, the IRS treats 80% of it ($40,000) as pre-tax and 20% ($10,000) as after-tax. You pay tax only on the $40,000 portion. The $10,000 after-tax portion comes out tax-free.

This rule applies even if your after-tax money sits in a different IRA account. Many people are surprised to learn that converting from one IRA does not isolate the tax calculation to that account alone. If you have after-tax contributions anywhere in the traditional IRA universe, they factor into the calculation.

State income tax on conversions

In addition to federal tax, most states tax Roth conversions as ordinary income. The state tax rate varies — some states have no income tax at all, while others tax conversions at rates between 3% and 13%. A few states, including Pennsylvania and Illinois, do not tax retirement income, which may include conversions depending on how the state defines the rule.

Check your state's tax treatment before converting a large amount. A conversion that makes sense from a federal perspective might be less attractive if your state adds significant tax on top. Some people time conversions to years when they have lower income, partly to reduce both federal and state tax exposure.

Paying the tax bill from conversion funds versus outside money

You have two choices for paying the tax: use money from outside the conversion, or pay it from the conversion amount itself. If you pay from outside money, the full conversion amount stays in your Roth account and grows tax-free. If you pay from the conversion funds, the IRS treats the amount you use for taxes as an additional distribution, and you owe tax on that too.

For example, if you convert $50,000 and owe $12,000 in tax, paying from outside money means $50,000 ends up in your Roth. Paying from the conversion funds means you withdraw $12,000 to cover taxes, which reduces your Roth balance to $38,000. The $12,000 withdrawal itself is also taxable, so your actual tax bill rises.

Most financial advisors recommend paying from outside money if you can afford it, because it maximizes the amount that grows tax-free in the Roth. However, if you do not have outside funds available, paying from the conversion is still an option — you just need to account for the additional tax owed on the withdrawal.

How conversions affect your income and tax brackets

A Roth conversion increases your taxable income for the year, which can have ripple effects on other parts of your tax return. A larger income may reduce tax deductions you would otherwise claim, increase the tax on Social Security benefits if you are retired, or disqualify you from certain tax credits. These secondary effects can make the true cost of a conversion higher than the straightforward tax rate suggests.

This is why many people convert in years when their income is already low — for instance, the year they retire before Social Security starts, or a year with a major loss or deduction. Spreading conversions across multiple years can also reduce the impact on any single year's tax bracket and minimize the secondary effects.

Frequently Asked Questions

Can I undo a conversion if the tax bill is too high?

You can reverse a conversion through a process called a recharacterization, but only within a narrow window. You must complete the recharacterization by the tax filing deadline (usually October 15 of the year after the conversion). After that deadline, the conversion is permanent and the tax is owed. Recharacterizations are rare and have specific IRS rules; consult a tax professional before attempting one.

Do I have to pay the tax upfront or can I pay it when I file my return?

You do not have to pay the tax upfront. The tax is due when you file your return the following spring. However, if your total tax liability for the year is large, the IRS may require estimated tax payments during the year to avoid penalties. Your tax professional can tell you whether you need to make quarterly payments based on the conversion amount.

What if I convert in December — when do I owe the tax?

The conversion is taxable in the year it occurs, regardless of when you make it. A December conversion is taxed on your return filed the following spring. The money must be in the Roth account by December 31 to count as a conversion for that tax year.

Does the conversion count as income for Medicare premiums or other benefits?

Yes. The conversion amount is added to your modified adjusted gross income (MAGI), which is used to calculate Medicare premiums, Affordable Care Act subsidies, and other benefit thresholds. A large conversion can increase your premiums or reduce your subsidy may be able to access. This effect typically applies two years after the conversion year, so a 2024 conversion affects your 2026 Medicare premiums.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.