The Roth vs Traditional Decision Tree: A Framework Based on Your Actual Numbers

The Roth vs Traditional question has a definitive answer for most people. It depends on one thing: whether your marginal tax rate is higher now or will be higher in retirement. The problem is that almost nobody calculates this. Here's a decision framework based on actual numbers.

The Core Trade-Off

Traditional IRA: you deduct contributions now, pay taxes on withdrawals later. Roth IRA: you pay taxes now, withdraw tax-free later.

If your tax rate is the same in both periods, the math is identical. A dollar that grows tax-deferred and is taxed at withdrawal produces the exact same after-tax amount as a dollar that's taxed first and grows tax-free. This is the fundamental insight that most Roth-vs-Traditional advice ignores.

The question isn't "which is better?" It's "will my marginal rate be higher or lower when I withdraw?"

The Decision Tree

Start here and follow the branches:

Branch 1: Income Above Roth IRA Limits?

In 2026, single filers earning above $161,000 MAGI and joint filers above $240,000 cannot contribute directly to a Roth IRA. If you're above these limits, your options are Traditional IRA (non-deductible if you have a workplace plan), backdoor Roth conversion, or maximizing your Roth 401(k) if available. This is a hard constraint, not a preference.

Branch 2: Early Career, Low Income?

If you're in the 12% or 22% bracket today, Roth is almost certainly the right call. Your income will likely be higher later. Paying 12% or 22% now to avoid paying 24-35% later is a straightforward trade. The younger you are, the more decades of tax-free growth you capture.

Branch 3: Peak Earning Years?

If you're in the 32% or 37% bracket and expect to be in a lower bracket in retirement, Traditional wins. A $7,000 Traditional contribution at the 37% bracket saves you $2,590 in taxes today. If you withdraw at a 24% effective rate in retirement, you pay $1,680 on the same amount. That's $910 saved per year. Over 20 years of contributions, that difference compounds significantly.

Branch 4: Uncertain About Future Rates?

Split the difference. Contribute to both Traditional and Roth in the same year (within the combined $7,000 limit for IRAs, or split your 401(k) contributions between pre-tax and Roth). Tax diversification hedges against uncertainty. You'll have both taxable and tax-free buckets to draw from in retirement, giving you flexibility to optimize withdrawals year by year.

The Numbers People Miss

Three factors that change the calculation and are routinely overlooked:

• State taxes. If you live in California (13.3% top rate) now but plan to retire in Florida (0%), Traditional gets a massive boost. The state tax savings alone can exceed the federal benefit of Roth contributions.
• Required Minimum Distributions. Traditional IRAs force withdrawals starting at 73 (75 after 2033). Large Traditional balances can push you into higher brackets in retirement. Roth IRAs have no RMDs, giving you more control over your taxable income.
• Social Security taxation.Up to 85% of Social Security benefits become taxable if your "combined income" exceeds $34,000 (single). Large Traditional IRA withdrawals push you above this threshold. Roth withdrawals don't count toward combined income.

Using Clarity to Run the Numbers

Clarity shows your retirement accounts alongside everything else in your financial picture. You can see your current 401(k) balance, IRA balances, contribution history, and estimated tax-deferred growth. The net worth forecasting tool projects future balances under different contribution scenarios.

This matters because the Roth-vs-Traditional decision isn't made in isolation. It depends on your total income, other deductions, state of residence, and retirement timeline. Seeing all of these in one dashboard makes the trade-off concrete instead of abstract.

The Bottom Line

If your marginal rate is low now (12-22%), choose Roth. If it's high now (32-37%) and you expect it to drop, choose Traditional. If you're unsure, split your contributions. And if you're above the Roth IRA income limit, look into backdoor Roth conversions or Roth 401(k) contributions.

The worst choice is not contributing at all because you couldn't decide between the two. Both are dramatically better than a taxable brokerage account for long-term retirement savings.