A Roth conversion is not right for everyone, and the decision depends on your current tax bracket, retirement timeline, and how much you have in traditional retirement accounts

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 that year, but the money then grows tax-free and you owe no tax when you withdraw it later. The core question is whether paying tax now at your current rate is better than paying tax later at a higher rate — or whether you simply want tax-free growth for the next 20 or 30 years.

This is a calculation, not a one-size-fits-all answer. The math changes based on your age, your income this year, what you expect to earn in retirement, and whether you have the cash on hand to pay the tax bill without touching the converted amount.

Key Takeaways

  • A Roth conversion makes more sense if you are in a lower tax bracket now than you expect to be in retirement, or if you want decades of tax-free growth before you need the money.
  • You must have cash outside the retirement account to pay the tax bill; converting and then withdrawing from the same account to cover taxes defeats much of the benefit.
  • Conversions can push you into a higher tax bracket in the year you convert, which may also affect Medicare premiums, student loan payments, or other income-based benefits.
  • If you are still working and have a 401(k) at your job, the "pro-rata rule" may complicate conversions if you also have a traditional IRA with pre-tax money.
  • A conversion is permanent — you cannot undo it, so the decision should be deliberate and based on your specific numbers, not general advice.

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

The strongest case for a conversion is when you know you will owe more tax later. This happens most often when you are between jobs, taking a sabbatical, or in early retirement before Social Security and required minimum distributions kick in. Your income is low this year, so the tax rate on the conversion is low. In 10 years, when you are drawing from multiple sources, that same money would be taxed at a higher rate.

Example: You are 55, you left your job, and you will not work again until 62. Your income this year is $40,000. You convert $50,000 from a traditional IRA. The conversion pushes your income to $90,000, and you pay tax at roughly 22 percent federal (the rate for that bracket in 2024). In retirement at 70, when you have Social Security, a pension, and required minimum distributions, your bracket might be 32 percent. You locked in the lower rate by converting now.

This window is real but narrow. It closes once you return to work or once required minimum distributions begin at age 73. If you are still working full-time, a conversion usually pushes you into a higher bracket that year, which erases the benefit.

When you have decades before you need the money

The longer the money sits in a Roth account untouched, the more the tax-free growth compounds. If you are 40 and converting money you will not touch until 75, the 35 years of growth without tax drag is powerful. If you are 72 and need the money in five years, that same conversion is much less valuable.

This is especially true if you are converting money that would otherwise sit in a low-yield traditional account. If your traditional IRA is earning 1 percent and you convert it to a Roth earning 5 percent, the difference compounds over time. But if you are converting to hold the same investments at the same returns, the benefit is purely the tax-free growth, which only matters if you have a long time horizon.

The tax bill you have to pay right now

This is the detail that stops many conversions cold. When you convert $100,000, you owe income tax on $100,000 in that year. If your tax rate is 24 percent, that is $24,000 due. You must pay this from money outside the retirement account — from a savings account, checking account, or other non-retirement source.

If you withdraw $100,000 from the traditional account, pay $24,000 in tax, and convert the remaining $76,000, you have only converted $76,000, not $100,000. You have also triggered a withdrawal that counts toward your income and may affect other benefits. The ideal scenario is having $124,000 in outside cash: convert $100,000 and pay the $24,000 tax from your savings without touching the retirement account.

Many people do not have that cash. If you are considering a conversion, the first step is asking whether you can actually afford the tax bill without derailing your emergency fund or other financial goals.

How a conversion affects your income-based benefits and taxes

In the year you convert, your income rises. This can push you into a higher tax bracket, which increases the tax you owe on the conversion itself. But it can also affect other things: Medicare premiums (which are higher at certain income thresholds), student loan repayment amounts, state taxes, and the taxation of Social Security benefits.

If you are close to a Medicare premium threshold or a tax bracket edge, a conversion might cost you more than you save. This is why the calculation has to include your whole tax picture, not just federal income tax on the conversion.

Some people spread conversions over multiple years to stay below these thresholds. Instead of converting $100,000 in one year, they convert $30,000 per year for three years, keeping their income lower each year and avoiding a spike into a higher bracket.

The pro-rata rule and why it matters if you have both IRAs and a 401(k)

If you have money in both a traditional IRA and a 401(k) at your current job, the pro-rata rule applies. When you convert part of your traditional IRA to a Roth, the IRS treats the conversion as coming from all your pre-tax retirement accounts proportionally, not just the IRA you are converting from.

Example: You have $100,000 in a traditional IRA and $400,000 in a 401(k), for $500,000 total in pre-tax accounts. You want to convert $50,000 from the IRA to a Roth. The IRS says 80 percent of your pre-tax money is in the 401(k) ($400,000 out of $500,000), so 80 percent of the conversion is treated as coming from the 401(k). You owe tax on $50,000, but you cannot avoid it by converting only the IRA.

The workaround is rolling the traditional IRA into your 401(k) first, then converting from the 401(k). Not all 401(k) plans allow this, so you have to check with your plan administrator. If your plan does not allow it, the pro-rata rule limits how much you can convert without a large tax bill.

Conversions are permanent and cannot be reversed

Before 2018, you could undo a Roth conversion by filing an amended tax return. That option is gone. Once you convert, the money is in the Roth account and stays there. If the market drops after you convert and you regret the decision, you cannot reverse it.

This is why the decision should be based on your own numbers and timeline, not on market timing or general advice. You are making a permanent choice about how that money will be taxed for the rest of your life.

Frequently Asked Questions

Should I convert if I think tax rates will go up in the future?

That is one reason to convert, but it is not enough by itself. Tax rates are uncertain, and you cannot predict them. The stronger reasons are your personal situation: you are in a low bracket now, you have decades before you need the money, or you have cash to pay the tax bill without disrupting your finances. If those are true, rising tax rates make the case stronger. If they are not true, betting on future tax rates is risky.

Can I convert just part of my traditional IRA?

Yes. You can convert $10,000, $50,000, or any amount. Many people convert in smaller chunks over multiple years to spread the tax bill and stay in a lower bracket each year. This is called a "ladder" conversion and is common for people in early retirement.

What happens if I convert and then need the money before age 59½?

Money you converted can be withdrawn tax-free and penalty-free anytime, as long as it has been in the Roth for at least five years. The five-year rule applies to each conversion separately, so a conversion you make at 50 can be withdrawn penalty-free at 51. Earnings on the converted money are different — those follow the normal Roth rules and may be taxed if withdrawn before 59½.

Does a conversion affect my Social Security benefits?

Indirectly. A conversion increases your income that year, which can affect how much of your Social Security is taxed if you claim before full retirement age. If you are coordinating your claiming strategy with a conversion, run the numbers with a tax professional to see the combined effect.

What if I convert and the market drops right after?

You still owe tax on the amount you converted, even if the account value falls. This is one reason some people convert in smaller amounts over time — it reduces the risk that a market drop will make the conversion regrettable. You cannot undo the conversion, so the timing risk is real.