When a Roth Conversion Makes Sense for Your Situation

A Roth conversion is worth considering if your tax rate is lower now than you expect it to be in retirement

A Roth conversion means moving money from a traditional IRA or 401(k) into a Roth account. You pay income tax on the amount you convert in the year you do it, but then that money grows tax-free and you can withdraw it tax-free later. The decision hinges on one thing: whether you'll pay less tax now than you would have paid if you'd waited and withdrawn the money in retirement.

This is not a choice everyone should make. It depends on your current income, your expected income in retirement, your age, and how much money you have in traditional accounts. There is no single right answer — the math is different for every person.

Key Takeaways

• A Roth conversion makes sense if your tax bracket this year is lower than the tax bracket you expect to be in when you withdraw the money in retirement.
• You pay ordinary income tax on the full amount you convert in the year you convert it, which can push you into a higher tax bracket that same year.
• Conversions are most common in years when your income drops — between jobs, after retirement but before Social Security starts, or after a major business loss.
• If you have both traditional and Roth IRAs, the IRS treats them as one account for conversion purposes, which can create unexpected tax bills.
• You cannot undo a conversion after the tax year ends, so the decision is permanent once you file your return.

When your current tax rate is lower than your expected retirement rate

The core reason to convert is tax rate arbitrage: paying tax at a lower rate now to avoid paying it at a higher rate later. This happens in specific situations.

If you retire before age 73 and before you start Social Security, you may have a year or two with very low income. A conversion in that window lets you move money into a Roth at a 12% federal tax rate instead of waiting until age 75 when you're forced to take Required Minimum Distributions and your income jumps. If you expect your retirement income to be high — because of a pension, rental income, or large investment gains — converting early can save you money.

If you're self-employed and had a down year, or if you took a voluntary pay cut, your income may be temporarily low. A conversion that year costs less than it would in a normal-income year.

When the tax bill will hurt you right now

The conversion itself creates a tax bill in the year you do it. If you convert $50,000, you owe income tax on $50,000 of ordinary income that year. For a single filer in 2024, that could mean moving from the 22% bracket into the 24% bracket, or higher.

If you don't have cash outside the IRA to pay that tax, you have to withdraw money from the IRA itself to cover it. That withdrawal is also taxable, which creates a spiral: you convert to save on taxes, but you have to withdraw more to pay the tax, which costs you more. This usually makes the conversion a bad move.

If you're in a high tax bracket already — because you have a well-paying job, a large bonus year, or significant investment income — a conversion may push you into an even higher bracket. Run the math before you commit. A conversion that costs you 35% in federal tax plus state tax may not be worth it.

The pro-rata rule and why it matters if you have both account types

If you have both a traditional IRA and a Roth IRA, the IRS does not let you convert only the Roth-may be able to access portion and leave the rest alone. Instead, it treats all your IRAs as a single pool for tax purposes.

Here's what that means: suppose you have a $100,000 traditional IRA and a $10,000 Roth IRA. You want to convert $20,000 to Roth. The IRS says you're converting 20% of your total IRA balance, which is $110,000. So 20% of the conversion is taxable ($4,000) and 80% is non-taxable ($16,000). You end up paying tax on $4,000 even though you only converted pre-tax money.

This rule is called the pro-rata rule. It applies to all IRAs you own — SEP-IRAs, straightforward IRAs, and traditional IRAs are all lumped together. It does not explore to 401(k)s, 403(b)s, or other employer plans, which are treated separately. If you have a large traditional IRA balance and a small amount of pre-tax money in a 401(k), you might convert the 401(k) money instead to avoid the pro-rata rule.

The timing of conversions around major life changes

Conversions are most useful in specific years, not every year. A year when you have unusually low income is the ideal time.

If you're retiring mid-year, you might convert in that year because your income is only half of normal. If you're between jobs, a conversion during the gap can make sense. If you sell a business or real estate at a loss, that loss can offset the conversion income. If you're waiting for Social Security to start at a higher age, the years before it starts are often low-income years.

The opposite is also true: do not convert in a year when you have a large bonus, a business sale, significant capital gains, or other one-time income. The conversion will be taxed at the highest marginal rate you hit that year.

How conversions affect Medicare premiums and other benefits

A conversion increases your taxable income for that year, which can affect other things beyond your federal tax bill.

Medicare premiums are based on your Modified Adjusted Gross Income (MAGI) from two years prior. A large conversion can push your MAGI higher, which increases your Part B and Part D premiums. The effect lasts for two years, then drops off. If you're close to a Medicare premium threshold, a conversion might cost you more in higher premiums than you save in taxes.

Conversions can also affect whether you're subject to the Net Investment Income Tax (3.8% on certain investment income) and whether you lose tax credits like the Earned Income Tax Credit or education credits. Run the full picture before converting.

The permanent nature of conversions and the recharacterization rule

Once you file your tax return for the year you convert, the conversion is locked in. You cannot undo it or change your mind later.

Before 2018, you could recharacterize a conversion — move the money back to a traditional IRA and undo the tax bill if the market dropped or you changed your mind. That option is no longer available. The Tax Cuts and Jobs Act eliminated recharacterization for conversions (though you can still recharacterize regular Roth contributions).

This means you need to be confident in your decision before you execute the conversion. If you convert and the market drops 20% the next month, you still owe the full tax bill on the original amount, even though the account is now worth less. This is a real risk, especially if you're converting a large amount.

Frequently Asked Questions

Can I convert just part of my traditional IRA?

Yes, you can convert any amount. But if you have multiple IRAs, the pro-rata rule applies to all of them together, not to each account separately. You cannot cherry-pick which dollars to convert.

What if I convert and then the market drops?

You still owe the full tax bill on the amount you converted, even if the account value dropped. You cannot undo the conversion or reduce the tax. This is why some people convert smaller amounts or spread conversions across multiple years.

Do conversions count toward the annual contribution limit?

No. Conversions are separate from annual contribution limits. You can convert any amount in any year, regardless of how much you've already contributed to Roth accounts that year.

Should I convert if I'm still working?

It depends on your income. If your job income is high, a conversion will be taxed at your highest marginal rate, which usually makes it expensive. If you have a low-income year coming up, waiting might be better. Some people convert in the year they retire, before their next job starts.

Can I convert a 401(k) directly to a Roth?

Yes. You can do an in-service conversion if your plan allows it, or you can roll the 401(k) to a traditional IRA first and then convert to Roth. The pro-rata rule does not explore to 401(k)s, so this can be a way to avoid the pro-rata problem if you have a large traditional IRA.