Traditional or Roth

THE CHOICE BETWEEN a traditional retirement account or a Roth is a frequent topic on HumbleDollar. The choice is generally framed as a choice between paying taxes up front (a Roth), or deferring taxes until withdrawal (traditional). I thought it would be interesting to evaluate a real-life example of how this choice might work out.

In December of 2016 my wife and I had an opportunity to each open a Roth IRA. My wife took a partial sabbatical that year, and that, combined with maxing out our 401k accounts, gave us a chance to each open a $4,500 Roth IRA. The maximum allowable contribution that year was $6,500 for those 50 and over. Up until then we had assumed that our marginal tax bracket would likely be lower in retirement, and focused on contributing to our employer’s traditional 401k plans. Despite that, we decided to move forward with opening a Roth IRA. I thought it would give us some tax diversity, and the opportunity to do Roth conversions when, and if, it made sense in the future. 

In December of 2016 we opened Roth IRAs at Vanguard and invested the $4,500 in their S&P 500 Index Fund. Those initial funds have been invested for almost 10 years. Over that decade we have added some additional funds, and have done a few conversions. I recently did a quick analysis to see how my Roth experience would have compared to investing in a traditional IRA.  

In 2016, our marginal tax bracket was 28%.  To contribute the $4,500 required $6,250 of pre-tax income. Due to some financial engineering over the last year, including selling our second home in late 2025, I expect our 2026 marginal tax bracket to stay within the 12% bracket. I’ve been looking at this closely because I’m considering doing a Roth conversion later this year. The table below shows the comparison between the Roth performance, and what a traditional IRA would have produced. The annual rate of return was determined using Nick Maggiulli’s S&P 500 Historical Return Calculator. The table shows that the Traditional IRA would have been the better choice, producing about $3,500 more in available funds, or about 22% more. This demonstrates that the primary driver in choosing between a Roth and a traditional qualified account is a consideration of the tax rates at the time of contribution and at the time of distribution. There have been a number of changes to the tax code in the last decade that have contributed to the result, but I certainly didn’t predict any of them. If you guess wrong, you pay the price in a higher tax bill. In the example above, the extra $1,750 invested in the traditional account produced an additional $6,143.31 in earnings. The lower tax rate at the distribution of the traditional IRA results in the $3,500 in extra funds. Even though the Roth IRA had tax free earnings growth, the initial larger tax rate overcame that advantage, when compared to the traditional IRA. Because of my pension and my wife’s social security benefit, 85% of her social security benefit is taxable income, so that is not a consideration in our tax calculation. I used Dinkytown’s 1040 Calculator to run a series of estimates of our 2026 tax return to assess if we want to execute a Roth Conversion this year. We are still 4 years from taking RMDs, and I will start my Social Security in a year when I turn 70. My current thinking is a conversion of about $40,000 will keep us in the 12% bracket. There would also be a small NJ state tax impact. My simple analysis reinforces what I’ve been taught. Roth contributions make the most sense when you think your current tax bracket is lower than when you expect to withdrawal the funds. There are secondary considerations, like no tax diversification, no RMDs, and uncertainty about future tax rates. If you intend to pass the funds to heirs, it might make sense to perform Roth conversions today at the 22% tax bracket if you intend to pass these accounts to heirs who may be in their peak earnings years. Not sure? I believe I recall several HumbleDollar contributors write something about splitting the difference? Richard Connor is a semi-retired aerospace engineer with a keen interest in finance. He enjoys a wide variety of other interests, including chasing grandkids, space, sports, travel, winemaking and reading. Follow Rick on Twitter @RConnor609 and check out his earlier articles.

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