Converting a Traditional IRA to a Roth is a tax decision, not an automatic move

A conversion means moving money from a traditional IRA (where contributions may have been tax-deductible) into a Roth IRA (where withdrawals in retirement are tax-free). You pay income tax on the amount you convert in the year you do it. Whether that trade-off makes sense depends on your current tax bracket, how long until you retire, and whether you expect to be in a higher or lower tax bracket later.

This is not a decision you make once and forget. The math changes if your income changes, if tax rates change, or if your retirement timeline shifts. Many people benefit from converting part of a traditional IRA over several years rather than all at once, because spreading the conversion across multiple years can keep you in a lower tax bracket each year.

Key Takeaways

  • Converting triggers a tax bill in the year you convert, calculated at your ordinary income tax rate for that year.
  • A conversion makes more sense if you expect to be in a higher tax bracket in retirement than you are now.
  • Converting while your income is temporarily low (a year you took unpaid leave, retired early, or had a business loss) can reduce the tax cost.
  • You have until the tax filing deadline (usually April 15 of the following year) to undo a conversion if the market drops or your situation changes.
  • If you have both traditional and Roth IRAs, the IRS treats all of them as one pool for tax purposes when you convert, which can create an unexpected tax bill.

The tax cost of converting happens immediately

When you convert $50,000 from a traditional IRA to a Roth, the IRS treats that $50,000 as income you received that year. If you are in the 22% federal tax bracket, you owe roughly $11,000 in federal tax on that conversion. You may also owe state income tax, depending on where you live.

The tax is due when you file your return for that year. You can pay it from the converted funds themselves (which reduces what actually lands in the Roth), or you can pay it from other money. Most people pay from outside the IRA to avoid shrinking the amount that gets the tax-free growth benefit.

This is why converting a large amount all at once can push you into a higher tax bracket. If you normally earn $80,000 a year and convert $100,000, your taxable income that year is $180,000, which may put you in the 24% bracket instead of the 22% bracket — meaning you pay more tax on both the conversion and your regular income.

Converting makes sense if you expect higher taxes later

The core logic: you convert now at a lower tax rate, and withdraw later at a higher tax rate, and come out ahead. This scenario is most common for people who are still working but expect to have significantly more retirement income than they do now — perhaps from a pension, Social Security, or required withdrawals from a large traditional IRA.

It also makes sense if you believe tax rates will be higher in the future than they are today. Tax rates are set by Congress and change over time. If you think rates will rise, converting at today's rates locks in a lower tax cost.

Conversely, if you are already in a high tax bracket and expect to be in a lower one in retirement, converting now means paying tax at a high rate to avoid paying it at a lower rate later — the opposite of what you want.

Low-income years are the best time to convert

If you take a year off work, retire early before Social Security starts, or have a business loss, your taxable income that year may be much lower than usual. That is the moment to convert, because the conversion gets taxed at your temporarily low rate instead of your normal rate.

Example: You retire at 62 and do not claim Social Security until 70. From 62 to 70, your only income might be a small pension. Converting $100,000 during those years might cost you 12% in tax instead of 24%. By the time you start withdrawing from the Roth at 70, you have eight years of tax-free growth, and the withdrawals do not count as income for Social Security purposes.

This strategy works only if you can actually afford to pay the tax bill without touching the IRA itself. If you have to convert $100,000 and then withdraw $25,000 from the same IRA to pay the tax, you have only converted $75,000 and wasted the opportunity.

The "pro-rata rule" can create a hidden tax bill

If you own both a traditional IRA and a Roth IRA, the IRS does not let you convert only the after-tax money from the traditional IRA and leave the pre-tax money behind. Instead, it treats all your IRAs as one account for conversion purposes.

Here is the problem: suppose you have a traditional IRA with $100,000 (all pre-tax contributions and growth) and a Roth IRA with $50,000. You want to convert $10,000 from the traditional IRA. The IRS says you are actually converting $10,000 out of a combined $150,000 pool, which is 6.7% Roth and 93.3% traditional. So you owe tax on 93.3% of the $10,000 you converted, not 100% of it — but you also cannot avoid the tax by converting only the after-tax portion.

This rule catches many people off guard. If you have a small traditional IRA with mostly after-tax contributions and a large Roth IRA, converting the traditional IRA can trigger a much larger tax bill than you expected. A tax professional can help you model this before you convert.

You can undo a conversion until the tax deadline

If you convert and then the market drops, or your situation changes, you can reverse the conversion by filing a form called a recharacterization with your IRA custodian. You have until the tax filing deadline (usually April 15 of the year after the conversion) to undo it.

This is useful if you convert $50,000 and the market falls to $35,000 before the deadline. You can undo the conversion, pay no tax, and try again later when the value recovers. You can also do this if you convert and then realize your income for that year is higher than you expected, making the tax bill larger than you wanted.

The deadline is firm. If you miss it, the conversion stands and you owe the tax, even if you later regret it.

Conversions affect Medicare premiums and Social Security taxation

A conversion increases your taxable income for that year, which can raise your Medicare premiums two years later. Medicare premiums are based on your income from two years prior, so a large conversion in 2024 affects your 2026 premiums.

A conversion also counts as income for the purpose of determining how much of your Social Security is taxable. If you are claiming Social Security and convert a large amount, more of your benefit becomes subject to income tax that year.

These effects are often overlooked but can be significant. If you are near the Medicare premium thresholds or claiming Social Security, model the conversion with a tax professional before you commit to it.

Frequently Asked Questions

Is there an income limit for converting a traditional IRA to a Roth?

No. Unlike direct contributions to a Roth IRA, which have income limits, anyone can convert a traditional IRA to a Roth regardless of how much they earn. This is sometimes called the "backdoor Roth" strategy when used intentionally by high-income earners.

Can I convert just part of my traditional IRA?

Yes. You can convert any amount you want, from a small portion to the entire balance. Many people convert part of their IRA each year to spread the tax cost across multiple years and stay in a lower bracket.

What happens to required minimum distributions if I convert?

Once you convert money to a Roth, it is no longer subject to required minimum distributions during your lifetime. This is one reason some people convert — it lets them keep the money invested longer without being forced to withdraw it. Traditional IRAs require withdrawals starting at age 73 (as of 2023).

Do I have to report a conversion on my tax return?

Yes. Your IRA custodian sends you a Form 1099-R reporting the conversion. You report it on your tax return using Form 8606. If you do not report it correctly, the IRS may tax the same money twice — once as a conversion and again as a withdrawal.

What if I convert and then need the money back?

You can withdraw from a Roth IRA at any time without penalty, but you will owe tax on the earnings portion (not the contributions). If you converted recently and the money has not grown much, the tax bill is small. If you need the money back within a few years of converting, the conversion probably was not worth the tax cost.