Roth IRAs tend to get a lot of hype, and for good reason: because you pay the taxes up front, your eventual withdrawals (assuming you meet the age and holding-period requirements—more on these below) are completely tax-free.
While we like “tax-free” as much as the next person, there are times when a traditional IRA will put more money in your pocket than a Roth would.
Making the Decision on What’s Best
Example. Say that your tax rate is 32 percent and that you will invest $5,000 a year in an IRA and earn 6 percent interest. Should you put the $5,000 a year into a Roth or a traditional IRA?
Say further that neither you nor your spouse is covered by a workplace retirement plan, so you can contribute the $5,000 a year without worry because it’s under the contribution limits. If your income is too high for the Roth IRA, you make the $5,000 contribution via the backdoor.
Traditional IRA
If you invest the $5,000 in a traditional IRA, you create a side fund of $1,600 ($5,000 x 32 percent). On the side fund, you pay taxes each year at 32 percent, making your side fund grow at 4.08 percent (68 percent of 6 percent).
Roth IRA
Roth contributions are not deductible; this means no side fund, so your annual investment remains at $5,000.
Cashing Out
For the Roth, your marginal tax rate at the time of your payout doesn’t matter because you paid your taxes before the money went into the account. The whole amount is now yours, with no additional taxes due.
But for the traditional IRA, your current tax bracket matters a great deal. You have taken care of the taxes on the side fund annually along the way, but the traditional IRA (both growth and contributions) is taxed at your current marginal tax rate at the time you cash out.
The table below shows you how this looks with tax rates of 22 percent, 32 percent, and 37 percent at the time you cash out (winners are in bold):
You can see that the traditional IRA needs a low tax rate at the time of cash-out to win. But even in the 22 percent cash-out tax rate, the Roth wins at the 40-year mark.
Rate of Growth
What about your rate of growth? Do variances here change things any? Let’s take a look.
Here, we’ll look at different rates of growth for a fixed period (30 years) before you withdraw your money. Once again, we’ll consider three different marginal tax rates at the time you cash out—22 percent, 32 percent, and 37 percent.
n the scenarios above, the traditional IRA/side fund combo wins only when your marginal tax rate is lower at the time of withdrawal and only at the lower growth rates.
At higher rates of return—9 percent and 12 percent, in our examples above—the Roth still wins, even if you’re in a higher tax bracket when you withdraw your money.
Tax Factor
What’s going on here? For starters, the side fund is not tax-favored in any way. Plus, taxes hobble your cash-out on the traditional IRA:
You pay taxes as you earn the money in the side fund.
You pay taxes on the accumulated growth inside the traditional IRA when you withdraw the money.
Looking into the Crystal Ball
What tax bracket will you be in years or decades from now?
Unfortunately, there’s no way to know for sure. Nobody can predict what the federal government will be doing, tax-wise, down the line—though we do think it’s a safe bet that federal income taxes will not be abolished!
A better strategy is to look at your individual tax situation. While, again, nothing is certain, you may be able to anticipate likely life events—such as retirement, kids leaving home, mortgage paid off—that will affect your time of investment and tax bracket one way or the other.
The length of time you plan to keep the investment matters. As we see in the first table, given enough time, the Roth eventually catches up and passes the traditional IRA, even if your tax bracket is lower at the time you cash out.
Similarly, there’s no way to be sure what rate of growth you’re going to get over several decades of investing. A very rough (but common) benchmark is a 10 percent return, pre-tax9—which, again, tends to favor the Roth in our example above.