You can do a Roth conversion at any time during the year, but the tax bill and income limits matter more than the timing

A Roth conversion is moving money from a traditional IRA, SEP-IRA, SIMPLE IRA, or workplace 401(k) into a Roth IRA. The IRS does not restrict when you do this — you can convert in January, June, or December. What matters is whether the conversion makes sense for your tax situation that year, and whether you meet the income thresholds that apply to direct Roth contributions (not conversions themselves, which have no income cap).

The practical timing question is not "can I" but "should I" — and that depends on your income, tax bracket, and whether you expect to be in a lower tax bracket this year than next. A conversion creates a tax bill in the year you convert, so most people time it strategically rather than randomly.

Key Takeaways

  • Roth conversions have no income limits and no annual contribution cap — you can convert as much as you want in a single year.
  • You pay income tax on the amount you convert in the year you convert it, so timing around a low-income year can reduce the tax hit.
  • If you have a traditional IRA with pre-tax money and a Roth IRA, the IRS treats them as one account for tax purposes when you convert — you cannot cherry-pick only the gains.
  • The deadline to complete a conversion is December 31 of the year you want it to count, and you report it on your tax return the following spring.
  • You can undo a conversion (called a recharacterization) only if you do it before the tax filing deadline, and only back to a traditional IRA, not to a different Roth.

Converting during a year when your income is lower than usual

The most common reason to time a conversion is to do it in a year when you expect lower income. If you took early retirement, had a job loss, or had a year with unusually low business income, that year is often the best time to convert. You pay tax on the conversion at your current (lower) tax rate rather than waiting until you have higher income again.

For example, if you normally earn $150,000 per year but took a sabbatical in 2024 and earned only $40,000, converting $50,000 from a traditional IRA to a Roth in 2024 means paying tax on that $50,000 at your 2024 rate, not your normal rate. The tradeoff is that the conversion itself counts as income for that year, so it may push you into a higher bracket than you would otherwise be in — but it is still often cheaper than converting in a normal-income year.

Converting before you start taking required distributions

Once you turn 73 (as of 2023; this age changes with law), the IRS requires you to withdraw a minimum amount from traditional IRAs each year, called a required minimum distribution or RMD. You cannot convert money that is subject to an RMD in that same year — you must take the RMD first, then convert the rest if you want to.

This creates a timing advantage: converting before you reach RMD age means you can move money to a Roth while you still have full control over how much you convert each year. Once RMDs start, your flexibility shrinks because the IRS requires you to withdraw a set amount regardless of your tax situation.

Converting after a market downturn

If your IRA balance drops significantly in value — say, from $200,000 to $140,000 after a stock market decline — converting at the lower value means you pay tax on $140,000 rather than $200,000. The account then grows tax-free from that lower base. This is sometimes called a "backdoor" conversion strategy, though it is not a backdoor — it is just smart timing.

The catch is that you cannot predict market timing reliably, and waiting for a downturn might mean missing years when your income is low. Most people who use this strategy are already planning a conversion and happen to do it when the market is down, rather than timing the market itself.

Converting after leaving a job or selling a business

If you leave employment or sell a business, you may have a year with lower income than usual. That year is often ideal for a conversion because your tax bracket is temporarily lower. You also may have access to a workplace 401(k) that you can roll into a traditional IRA and then convert to a Roth — something you cannot do while still employed at that company (in most cases).

Plan this with a tax professional if possible, because the conversion amount can be large and the tax bill significant. But the opportunity to convert at a low tax rate may not come again for years.

The December 31 deadline and tax year rules

A conversion must be completed by December 31 of the year you want it to count toward. "Completed" means the money has actually moved to the Roth IRA, not just that you have requested it or started paperwork. If you initiate a conversion on December 28 but the transfer does not settle until January 3, it counts as a 2025 conversion, not 2024.

You report the conversion on your tax return for that year, filed the following spring. The IRS does not send you a bill for the conversion tax — you calculate it when you file your return. If you owe more tax than you have already paid through withholding or estimated payments, you will owe it when you file.

Undoing a conversion if your circumstances change

You can undo a Roth conversion by recharacterizing it back to a traditional IRA, but only if you do so before the tax filing deadline (usually April 15, plus extensions). You cannot recharacterize a conversion into a different Roth IRA — only back to a traditional IRA. If you converted and the market dropped sharply afterward, or your income turned out higher than expected, recharacterizing lets you reverse the move and redo it later if you want.

Recharacterization is not common, but it is useful as a safety valve. You must notify both your IRA custodian (the bank or brokerage holding the account) and the IRS. Your custodian can walk you through the process, and you report it on an amended tax return or Form 8606.

Frequently Asked Questions

Can I convert if I have both a traditional IRA and a Roth IRA?

Yes, but the IRS treats all your traditional IRAs as one account for conversion purposes. If you have $100,000 in a traditional IRA and $50,000 in a Roth, and you convert $30,000, you cannot choose to convert only the after-tax money — the conversion is treated as coming proportionally from all your traditional IRAs. This is called the pro-rata rule and often surprises people.

What if I convert and then my income ends up higher than I expected?

You still owe tax on the conversion at your actual income for that year. You cannot undo it after the filing deadline. This is why some people recharacterize before April 15 if circumstances change — but once that deadline passes, the conversion is locked in. Plan conservatively if you are unsure about your year-end income.

Can I convert a 401(k) directly to a Roth, or does it have to go through a traditional IRA first?

Many 401(k) plans allow direct conversions to a Roth 401(k) or Roth IRA without rolling to a traditional IRA first. Check with your plan administrator. If your plan does not allow it, you can roll the 401(k) to a traditional IRA and then convert from there, but that triggers the pro-rata rule if you have other traditional IRAs.

Do I have to convert the whole account, or can I convert part of it?

You can convert any amount, from a small portion to the entire account. There is no minimum or maximum per conversion. However, if you have multiple traditional IRAs, the pro-rata rule applies to all of them combined, so converting part of one account still counts the pre-tax money from all your traditional IRAs.

What happens if I convert and then need the money back?

Once money is in a Roth IRA, you can withdraw contributions (the amount you put in) at any time without penalty. But if you withdraw earnings (the growth), you may owe a 10% penalty plus income tax if you are under 59½ and have not held the Roth for five years. Plan conversions assuming the money will stay invested.