You owe income tax on the converted amount in the year you convert, and you pay it when you file your tax return

A Roth conversion moves money from a traditional IRA (or similar pre-tax account) into a Roth IRA. The IRS treats the money you move as income in that tax year, even though you do not receive it as a paycheck. You report this income on your tax return and pay tax on it along with your other income — there is no separate payment or form to the IRS beyond your regular return.

The amount you owe depends on how much you converted and your total income that year. If you converted $50,000, you will owe federal income tax on that $50,000 as if it were wages. Your tax bracket determines the rate. You may also owe state income tax, depending on where you live.

The conversion itself does not trigger withholding, so you will not see tax taken out automatically. This means you may need to set aside money to pay the tax bill when it comes due, or adjust your withholding from other income sources to cover it.

Key Takeaways

  • Report the full converted amount as ordinary income on your tax return for the year the conversion happened, using Form 8606.
  • You owe federal income tax at your regular tax rate, plus any state income tax your state charges on conversions.
  • The conversion does not automatically withhold tax, so you may need to pay estimated tax or adjust withholding from your job to avoid owing a large bill at tax time.
  • If you have a traditional IRA with pre-tax and after-tax money mixed together, the IRS pro-rata rule requires you to calculate tax on a portion of the entire balance, not just the amount you converted.
  • You can convert back (called a recharacterization) only in limited circumstances, but doing so before tax day can undo the tax liability if done correctly.

Which form reports the conversion to the IRS

Form 8606 is the form that reports your Roth conversion. You file it with your tax return (Form 1040) for the year you converted. The form asks for the amount converted, the value of your IRAs on December 31 of that year, and whether you had any after-tax contributions in those accounts.

Your IRA custodian (the bank or brokerage holding your account) will send you a Form 5498 in May showing the conversion. This is informational only — you do not file it with the IRS, but you use the numbers from it to fill out Form 8606. If you do not receive a Form 5498, contact your custodian and ask for the December 31 account value and the conversion amount.

Form 8606 also tracks your basis — the after-tax money you have already paid tax on. This matters because if you have both pre-tax and after-tax money in your traditional IRAs, the pro-rata rule applies, and you cannot convert only the after-tax portion tax-free.

How the pro-rata rule affects what you owe

The pro-rata rule is the most common mistake in Roth conversions. It says: if you have any pre-tax money in any traditional IRA, SEP IRA, or straightforward IRA on December 31 of the conversion year, you cannot convert only the after-tax money and avoid tax on it. Instead, the IRS treats your conversion as coming proportionally from both pre-tax and after-tax money.

Here is a concrete example: you have a traditional IRA with $80,000 in pre-tax contributions and $20,000 in after-tax contributions (basis). You want to convert the $20,000 after-tax portion to a Roth. Your total balance is $100,000. The pro-rata rule says 80 percent of your conversion is pre-tax money, so you owe tax on $16,000 of the $20,000 you converted. You can only move $4,000 tax-free.

The pro-rata rule applies to your entire IRA balance across all accounts you own, added together. If you have a traditional IRA at one bank and a SEP IRA at another, the IRS counts both. The only way to avoid the pro-rata rule is to have zero pre-tax money in all your IRAs on December 31 of the conversion year. Some people roll their pre-tax IRA balance into a 401(k) at work before converting, which removes it from the pro-rata calculation.

Paying the tax bill when it is due

You pay tax on the conversion when you file your tax return, which is normally due April 15 of the following year (or the next business day if April 15 falls on a weekend). The tax is included in your total tax liability for the year and is paid along with any other taxes you owe.

If you expect to owe a large amount, you have two options to avoid underpayment penalties. First, you can make estimated tax payments to the IRS in quarterly installments (April 15, June 15, September 15, and January 15). Second, you can increase the withholding from your paycheck if you have a job, by submitting a new Form W-4 to your employer. Either method tells the IRS you are paying as you go, which avoids penalties.

If you do neither and owe more than $1,000 when you file, the IRS may charge an underpayment penalty on top of the tax itself. The penalty is small but adds up if you convert a large amount and do not plan ahead. Many people set aside 20 to 30 percent of the converted amount in a savings account to cover the tax bill.

State income tax on conversions

Most states that have an income tax will tax your Roth conversion as ordinary income in the year it happens. A few states do not tax retirement account conversions at all. Your state tax rate varies, but it is typically 3 to 10 percent depending on your income and state.

If you live in a state with no income tax (such as Florida, Texas, or Wyoming), you owe no state tax on the conversion. If you moved during the year, you may owe tax to two states — the state where you lived when you converted and the state where you lived on December 31. Check your state's tax agency website or ask a tax preparer in your state to confirm the rules.

Some states allow you to deduct the conversion from state taxable income if you have significant losses in other investments that year, but this is rare. In most cases, state tax on a conversion is straightforward: the state taxes the full converted amount at your state's income tax rate.

What happens if you convert and then change your mind

You can undo a Roth conversion by recharacterizing it — moving the money back to a traditional IRA. However, the rules are strict. You must recharacterize by the tax filing important date for the year you converted (normally October 15 if you file an extension). Once that important date passes, the conversion is permanent and you cannot undo it for tax purposes.

If you recharacterize before the important date, you report the recharacterization on Form 8606 when you file your return. The conversion is treated as if it never happened, and you owe no tax on it. However, you must also reverse any earnings the money made while it was in the Roth. If your $50,000 conversion grew to $52,000, you move back $50,000 and the $2,000 in earnings stays in the Roth and is taxable to you.

Recharacterization is useful if the market drops after you convert and you want to avoid paying tax on a larger amount than the money is now worth. It is also useful if you convert and then realize your income is higher than expected that year, pushing you into a higher tax bracket. But you must act before the filing important date — there is no extension for recharacterization itself.

Conversions and Medicare premiums

A Roth conversion increases your income for the year, which can raise your Medicare premiums if you are on Medicare. The IRS uses your Modified Adjusted Gross Income (MAGI) from two years prior to set your premiums. If you convert in 2024, your 2026 Medicare premiums may go up based on the higher income.

You can file Form SSA-44 with Social Security to request a review of your premiums if your income dropped after the year you converted. This is not automatic — you must request it and provide proof that your income is now lower. Many people factor this into their conversion decision, especially if they are close to the income thresholds that trigger higher premiums.

Frequently Asked Questions

Do I have to pay the tax on a conversion all at once?

No. You can spread the tax payment across the year using estimated tax payments or by adjusting your paycheck withholding. You can also pay the full amount when you file your return in April. The IRS does not require a lump sum payment — it only requires that you pay by the tax important date or face underpayment penalties.

What if I do not have enough money to pay the tax bill?

You can still file your return and pay what you can. The IRS will charge interest on the unpaid balance, and you may owe penalties, but you can set up a payment plan. The IRS offers short-term plans (120 days or less) at no cost and long-term installment agreements for larger amounts. Contact the IRS or work with a tax professional to arrange this.

Can I use money from the Roth conversion itself to pay the tax?

Yes, but it is not recommended. If you convert $50,000 and use $10,000 of it to pay the tax, you only moved $40,000 into the Roth. You still owe tax on the full $50,000 you converted, so you end up paying tax on money that never made it into the Roth account. Most people pay the tax from other savings or income.

Does a Roth conversion affect my tax refund?

It can. The conversion increases your taxable income, which may reduce your refund or turn it into a balance due. If you normally receive a refund, a large conversion might mean you owe money instead. This is why planning ahead and adjusting your withholding is important.

What if I made a mistake on Form 8606?

You can file an amended return (Form 1040-X) to correct it. You have three years from the original filing date to amend. If you reported the wrong conversion amount or forgot to account for the pro-rata rule, file the amendment as soon as you notice the error. The IRS will recalculate your tax and send you a bill or refund.