Roth vs. Traditional: The Tax Rate Crossover

Every dollar contributed to a retirement account will be taxed exactly once. The fundamental choice between a Roth and a Traditional account lies in deciding whether to pay taxes on that dollar now or defer them until later. This decision is crucial for long-term financial planning and significantly impacts your retirement savings.

With a **Roth account**, contributions are made with after-tax dollars, leading to tax-free withdrawals in retirement. This offers predictability and is highly advantageous if you anticipate being in a higher tax bracket during your retirement years.

Conversely, a **Traditional account** allows for tax-deductible contributions, deferring taxes until retirement, when withdrawals are taxed as ordinary income. This approach is generally beneficial if you expect to be in a lower tax bracket during retirement than you are today.

The decision primarily hinges on your projection of future tax rates relative to your current tax rate. If you foresee a **lower tax rate in retirement**, a Traditional account is often more advantageous, offering a tax deduction at your current higher rate and lower taxes in retirement. Conversely, if you anticipate a **higher tax rate in retirement**, a Roth account is preferable, securing tax-free withdrawals later and shielding your savings from potentially higher future tax burdens.

Even if tax rates are **roughly equal**, Roth accounts can offer subtle advantages. While many assume their income and tax rate will decrease in retirement, several factors can unexpectedly elevate retirement tax rates.

**Required Minimum Distributions (RMDs)** are mandatory withdrawals the IRS imposes on traditional retirement accounts. The SECURE 2.0 Act updated these ages: for those born between 1951 and 1959, RMDs generally begin at age 73. For those born in 1960 or later, RMDs commence at age 75. Substantial traditional account balances can lead to RMDs pushing individuals into higher tax brackets than anticipated.

**Social Security taxation** is another factor. If combined retirement income exceeds $34,000 for single filers or $44,000 for married couples filing jointly, up to 85% of Social Security benefits become taxable. Large traditional IRA or 401(k) withdrawals can easily trigger these thresholds.

**Tax rate uncertainty** also plays a role. Current marginal tax rates are subject to change, with some provisions set to sunset in 2026. Paying taxes now at known rates through a Roth account provides certainty and hedges against potential future tax increases.

**Medicare Income-Related Monthly Adjustment Amounts (IRMAA)** are surcharges on Medicare Part B and Part D premiums for higher-income beneficiaries, based on income from two years prior. Significant RMDs from traditional accounts can directly contribute to higher reported income, potentially increasing Medicare premiums.

**Tax diversification** is a powerful strategy. Holding both Roth and Traditional accounts provides flexibility in managing taxable income during retirement. In high-income years, tax-free Roth withdrawals can prevent bracket creep. In lower-income years, Traditional withdrawals can be utilized. This strategic flexibility offers significant value.

**Estate planning** also favors Roth accounts. Inherited Roth IRAs receive favorable tax treatment; non-spouse beneficiaries generally must distribute inherited IRAs within 10 years, but Roth distributions during this period are tax-free.

Crucially, **Roth IRAs have no RMDs** during the original owner's lifetime, unlike Traditional IRAs and 401(k)s which mandate distributions at ages 73 or 75. For those not needing the income, the absence of RMDs in Roth accounts allows investments to grow tax-free for longer.

Understanding contribution limits and income thresholds is essential. For 2026, the **401(k) employee deferral limit is $24,500**, with an additional **catch-up contribution of $8,100** for those aged 50 and over. The **IRA contribution limit for 2026 is $7,500**.

For Roth IRA contributions, **Modified Adjusted Gross Income (MAGI) phase-out limits for 2026** are: single filers, $153,000–$168,000; married couples filing jointly, $242,000–$252,000. MAGI within these ranges reduces or eliminates allowable Roth IRA contributions.

For **young investors in low tax brackets** (e.g., 12% or 22%) early in their careers, Roth contributions are almost certainly superior. Their income and tax bracket are highly likely to be higher later in their careers and retirement. Paying taxes now at a low rate locks in significant long-term tax savings.

• **In the 12% bracket:** Almost always favor Roth contributions.
• **In the 22% bracket:** Lean towards Roth, especially if early career or uncertain about retirement income.
• **In the 24% bracket:** This is a judgment call; model it with your specific financial situation.
• **In the 32%+ brackets:** Lean towards Traditional contributions, particularly if you anticipate a significant drop in income during retirement.

When in doubt, **tax diversification** is prudent. Contribute enough to a Traditional account to capture any employer match, then direct additional contributions to a Roth account. This strategy mitigates regret regardless of future tax rate movements and provides valuable flexibility in retirement.

---

*Related: [The Backdoor Roth](./backdoor-roth-howto) is the technique for high earners above the Roth income limit. [The Roth Conversion Ladder](./roth-conversion-ladder) is the strategy for accessing Roth money before 59½ in early retirement.*