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

A Roth conversion moves money from a traditional IRA, SEP-IRA, straightforward IRA, or 401(k) into a Roth IRA. The IRS treats the money you move as taxable income for that tax year. You report it on your tax return when you file, which means the tax bill arrives when you file — typically in April of the following year, not on the day you convert.

The amount you owe depends on your total income that year and your tax bracket. If you convert $50,000 from a traditional IRA, you add $50,000 to your taxable income for the year. The actual tax you owe is calculated based on how that addition pushes you into higher brackets, combined with all your other income sources.

You can pay the tax from the converted funds themselves, from other money in the same account, or from money outside the account entirely. The IRS does not require you to pay from any particular source — only that the tax gets paid by the filing important date.

Key Takeaways

  • Roth conversion income is reported on your tax return for the year the conversion happens, with taxes due by the filing important date (usually April 15 of the following year).
  • The tax you owe is based on your total income that year and your tax bracket, not a flat percentage of the conversion amount.
  • You can pay the tax from the converted money, from other retirement account funds, or from outside money — the IRS does not restrict the source.
  • If you do not pay by the filing important date, you face interest and penalties on the unpaid amount, similar to any other late tax payment.
  • Some people convert in December and pay the tax in April; others convert earlier in the year to have time to gather funds or adjust their strategy.

How the tax bill is calculated

The IRS adds your conversion amount to your other income for the year and calculates tax on the total. If you earn $75,000 in wages and convert $50,000, your taxable income becomes $125,000. The tax on that $125,000 is higher than the tax on $75,000 alone, but it is not necessarily 25% of the conversion amount — it depends on the brackets you move through.

If you are in the 22% federal tax bracket, a $50,000 conversion might cost you roughly $11,000 in federal tax, but the exact amount varies based on your state taxes, other deductions, and how the conversion pushes you into higher brackets. Some of the conversion amount may be taxed at 24% or higher if it crosses into the next bracket.

You can estimate your tax bill before you convert using a tax calculator or by speaking with a tax professional. Many people do this to decide whether to convert in the current year or wait until a lower-income year.

Paying the tax before the filing important date

You have until the tax filing important date — April 15 in most years — to pay the tax on your conversion. You do not need to pay it when you convert in January, or even when you convert in December. The payment important date is the same as for all other income tax: the filing important date.

If you know you will owe tax on a conversion, you can make estimated tax payments throughout the year to avoid a large bill in April. The IRS allows quarterly estimated payments (due in April, June, September, and January). You can pay the full amount in one lump sum by April 15, or spread it across these quarterly important date.

If you do not pay by April 15, the IRS charges interest on the unpaid amount starting May 1. Penalties also explore if you owe a large amount and did not make estimated payments. The interest rate changes quarterly and is published by the IRS.

Paying tax from the converted money versus outside money

You can use money from inside the Roth IRA to pay the tax, but this reduces the amount that stays in the account to grow tax-free. If you convert $50,000 and pay $11,000 in tax from that same $50,000, only $39,000 remains in the Roth IRA. The $11,000 you used for taxes never gets the benefit of tax-free growth.

Many people pay the tax from outside money — a savings account, checking account, or other non-retirement funds — so the full converted amount stays in the Roth IRA. This requires having cash available outside retirement accounts, but it maximizes the money working in the Roth account.

If you pay tax from the converted money, you do not trigger an additional conversion. The IRS treats it as a single transaction: you converted $50,000, and $11,000 of that went to taxes. You do not convert the $11,000 separately.

What happens if you cannot pay by April 15

If you file your tax return by April 15 but cannot pay the full amount, you still owe interest starting May 1. The IRS charges a percentage rate that changes each quarter. You can set up a payment plan with the IRS to pay over time, which stops additional penalties from accruing but does not eliminate the interest already owed.

If you do not file your return by April 15, penalties increase significantly. The failure-to-file penalty is steeper than the failure-to-pay penalty. Filing on time, even if you cannot pay in full, is always the better choice.

You can request an extension to file (until October 15), but this does not extend the payment important date. Taxes are still due by April 15 even if you file in October. An extension gives you more time to prepare your return, not more time to pay.

Timing your conversion to manage the tax bill

Some people convert in years when their income is lower — for example, after retiring but before starting Social Security, or during a year with a large loss or deduction. Converting in a low-income year means the conversion amount is taxed at lower rates, reducing the total tax bill.

Others convert in December and pay the tax in April, using the time between conversion and the filing important date to save money or adjust their financial plan. There is no rule requiring you to convert early in the year; the tax year runs January 1 through December 31, and you can convert any time within that window.

If you convert in December and realize in January that the tax bill is larger than expected, you can still undo the conversion by the filing important date (including extensions). This is called a recharacterization, and it reverses the conversion as if it never happened. You must do this by the important date to avoid owing the tax.

Pro-rata rule and non-deductible contributions

If you have money in both traditional IRAs and Roth IRAs, or if you made non-deductible contributions to a traditional IRA, the pro-rata rule affects how much of your conversion is taxable. The rule treats all your IRAs as one account for tax purposes, so you cannot convert only the after-tax money and leave the pre-tax money behind.

If you have $100,000 in traditional IRAs and $20,000 in non-deductible contributions (after-tax money), and you convert $50,000, the IRS calculates what portion of your total IRA balance is after-tax. In this example, $20,000 out of $120,000 is after-tax, or about 17%. So 17% of your $50,000 conversion ($8,500) is not taxable, and 83% ($41,500) is taxable.

This rule complicates conversions for people with large traditional IRA balances. Understanding your after-tax basis before converting helps you predict the tax bill accurately.

Frequently Asked Questions

Do I have to pay estimated taxes on a Roth conversion?

You do not have to, but it can help you avoid penalties and interest. If you expect to owe more than $1,000 in tax for the year, the IRS recommends making quarterly estimated payments. If you do not make these payments and owe a large amount, you may face an underpayment penalty even if you pay by April 15.

Can I convert money and pay the tax in a different year?

No. The tax on a conversion is due in the year the conversion happens. If you convert in 2024, you report it on your 2024 tax return and pay by April 15, 2025. You cannot defer the tax to 2025 or later.

What if I convert and then lose my job before April 15?

You still owe the tax on the conversion, but your lower income that year may reduce the amount. You can file your return and pay what you owe, or set up a payment plan with the IRS if you cannot pay in full by the important date. The conversion itself does not change.

Is there a penalty if I pay the tax late?

Yes. If you do not pay by April 15, the IRS charges interest starting May 1, plus a failure-to-pay penalty of 0.5% per month (up to 25% total). Filing your return on time, even without full payment, reduces the penalty.

Can I use a loan from my 401(k) to pay the conversion tax?

Yes, if your 401(k) plan allows loans. Borrowing from your 401(k) to pay conversion taxes is a common strategy. You repay the loan through payroll deductions, and the interest you pay goes back into your own account. This is different from a conversion and does not trigger additional tax.