You owe federal income tax on the converted amount in the year you convert, but you do not have to pay it immediately

A Roth conversion creates a tax bill in the year the conversion happens. The IRS treats the money you move from a traditional IRA (or similar account) to a Roth IRA as ordinary income for that tax year. You report it on your tax return when you file, usually the following spring. You do not owe the money to the IRS on the day you convert — you owe it when your taxes are due, which is typically April 15 of the next year.

The amount you owe depends on how much you converted and your tax bracket that year. If you converted $50,000 from a traditional IRA to a Roth, you will report $50,000 as additional income on your federal return. Your state may also tax it, depending on where you live. Some states do not tax retirement account conversions; others do.

The key decision is whether to pay the tax from the conversion itself or from other money you have. If you use money from outside the Roth account to pay the tax, you keep more money growing tax-free inside the Roth. If you use money from inside the conversion to pay the tax, you reduce the amount that ends up in the Roth and you may face an early withdrawal penalty if you are under 59½.

Key Takeaways

  • The tax on a Roth conversion is due when you file your tax return the following spring, not on the day you convert.
  • You report the full converted amount as income on your federal return, and your state may tax it too depending on your state's rules.
  • Paying the tax from outside money (not from the conversion itself) keeps more money growing tax-free in the Roth.
  • If you use conversion money to pay the tax and you are under 59½, you may owe an early withdrawal penalty on that portion.
  • You can make estimated tax payments throughout the year to avoid a large bill in April, though this is optional.

How the tax bill is calculated and reported

The IRS requires you to report a Roth conversion on Form 8606, which you attach to your federal tax return. This form tells the IRS how much you converted and whether any of the conversion came from pre-tax money (which is taxable) or after-tax money (which is not). Most conversions are fully taxable because most people's traditional IRAs contain pre-tax contributions or earnings.

Your tax bill is the converted amount multiplied by your marginal tax rate — the rate you pay on your highest dollars of income that year. If you converted $50,000 and your marginal rate is 24%, you owe $12,000 in federal tax. If your marginal rate is 32%, you owe $16,000. Your actual rate depends on your total income for the year, your filing status, and whether you take the standard deduction or itemize.

State tax varies widely. New York, California, and most other states tax Roth conversions as ordinary income. A handful of states — including Pennsylvania, Tennessee, and Texas — do not tax retirement income at all. A few others have partial exemptions. You can find your state's rule by searching "[your state] Roth conversion tax" or asking a tax professional.

Paying the tax from your own money versus the conversion

You have two basic choices: pay the tax bill from money outside the Roth account, or use money from the conversion itself. The choice matters because it affects how much ends up growing tax-free in the Roth.

If you pay from outside money — a checking account, a taxable brokerage account, or a bonus from work — the full converted amount stays in the Roth and grows tax-free. This is the strongest financial move if you have the cash available. You convert $50,000, you owe $12,000 in tax, you pay the $12,000 from your bank account, and $50,000 grows tax-free in the Roth.

If you use money from the conversion to pay the tax, you reduce what ends up in the Roth. You convert $50,000, you use $12,000 of it to pay the tax bill, and only $38,000 grows tax-free in the Roth. Additionally, if you are under 59½, the $12,000 you withdrew to pay the tax may be subject to a 10% early withdrawal penalty — adding another $1,200 to your bill. This penalty applies to the portion you withdrew, not the portion that stayed in the Roth.

Making estimated tax payments to spread the cost

You do not have to wait until April to pay the tax. You can make estimated tax payments to the IRS throughout the year. This spreads the cost into four payments (usually due in April, June, September, and January) instead of one large payment in April.

Estimated payments are optional, but they can help if a large conversion would push you into a higher tax bracket or if you simply prefer to pay gradually. You calculate your estimated tax using Form 1040-ES, which the IRS provides free on its website. You can also work with a tax professional to figure out the right amount.

If you do not make estimated payments and you owe more than $1,000 in tax for the year, the IRS may charge you a penalty for underpayment. The penalty is usually small — a few dollars — but it exists. Making estimated payments avoids this penalty entirely.

What happens if you cannot pay the full amount by April

If you cannot pay the entire tax bill when you file your return, you can request a payment plan from the IRS. Short-term plans (120 days or less) are free. Long-term plans charge a setup fee and monthly interest. The IRS also charges interest on any unpaid tax from the original due date, so the longer you wait, the more you owe.

You can set up a payment plan online through the IRS website, by phone, or by mail. The IRS will work with you on a monthly payment amount based on what you can afford. However, you must still file your tax return on time even if you cannot pay — filing late carries a separate penalty.

Some people also consider taking a loan from their 401(k) or borrowing from family to cover the tax bill, rather than setting up a payment plan. Either approach is legal, but each has trade-offs. A 401(k) loan reduces your retirement savings and requires repayment; a family loan may create personal complications. A payment plan lets you spread the cost without borrowing.

State taxes and special situations

Most states that tax income will tax your Roth conversion the same way the federal government does — as ordinary income in the year of conversion. However, a few states have rules worth knowing. If you move to a new state after converting, you may owe tax to both your old state (for the part of the year you lived there) and your new state. Some states also allow you to spread the conversion over multiple years for state tax purposes, even though the IRS requires you to report it all in one year.

If you are retired and receiving Social Security, a large Roth conversion can push your income high enough to trigger taxation of your Social Security benefits. This is a separate tax issue from the conversion itself, but it can add significantly to your bill. A tax professional can model this scenario before you convert.

Frequently Asked Questions

Can I convert money and not pay taxes on it?

No. The IRS requires you to pay tax on the full amount you convert from a pre-tax account to a Roth, with limited exceptions. If part of your traditional IRA contains after-tax contributions (money you already paid tax on), that portion is not taxed again. A tax professional can calculate this using the pro-rata rule.

What if I convert in December — do I pay tax in December or April?

You pay in April (or whenever you file your return). The year you convert determines the tax year. A December conversion is reported on the tax return you file the following April, not on an earlier return. You can make an estimated payment in January if you want to pay sooner.

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

Yes, the converted amount is counted as income for the year of conversion. This can affect Medicare premiums (which are based on income from two years prior), Medicaid, and other need-based programs. If you receive any means-tested benefit, consult a professional before converting.

Can I undo a conversion if I change my mind about the tax bill?

You can undo a conversion through a process called a recharacterization, but only within certain time limits and only if you meet specific conditions. The rules changed in 2018 and are now very restrictive. Speak with a tax professional immediately if you want to explore this option.