Comparison · Reviewed 3 October 2026
Traditional 401k saves taxes now; Roth saves taxes later. Choose based on whether you expect higher tax brackets in retirement.
In a 32% bracket, a $24,500 Traditional contribution (the 2026 limit) cuts this year's tax by $7,840. The same dollars as Roth are taxed now and come out tax-free later. Which comes out ahead depends on your tax rate in retirement compared with today.
Contribution mechanics
| Factor | Traditional 401k | Roth 401k |
|---|---|---|
| $24,500 contribution (2026 limit) | Reduces taxable income by $24,500 | No tax deduction; already taxed |
| Tax impact on contribution | Save 32% tax = $7,840 (32% bracket) | Pay 32% tax = $7,840 (32% bracket) |
| Tax on growth | Tax-deferred (taxed when withdrawn) | Yes (compound tax-free forever) |
| Withdrawal tax | Taxed as ordinary income (10–37% bracket) | Tax-free (0%) |
| Withdrawals trigger RMDs at 73? | Yes (must withdraw annually, taxed) | No (can withdraw or leave forever) |
30-year scenario: same after-tax cost, 7% growth, 30 years
A fair comparison holds your take-home cost equal. In a 32% bracket, a $24,500 Traditional contribution costs $16,660 of take-home pay (the other $7,840 is tax you did not pay), so the matching Roth contribution is $16,660. Figures assume end-of-year contributions and a constant 7% return; they are illustrations, not forecasts.
| Outcome | Traditional ($24,500/yr) | Roth ($16,660/yr, same take-home cost) |
|---|---|---|
| Account value at retirement | $2,314,289 (tax-deferred) | $1,573,717 (tax-free) |
| After tax at 32% in retirement | $1,573,717 | $1,573,717 |
| After tax at 22% in retirement | $1,805,146 | $1,573,717 |
Key insight: at the same tax rate now and in retirement, Traditional and Roth end up identical; the tax is simply paid at a different time. The choice turns on whether your retirement rate will be lower (Traditional ahead) or higher (Roth ahead). Roth does shelter more in one case: if you contribute the full $24,500 as Roth, you are effectively putting more after-tax money inside the tax-advantaged limit than a Traditional contributor can.
When Traditional 401k wins
- High earner (32–37% bracket) contributing now
- Expect lower tax bracket in retirement (e.g., retired early at 22% bracket)
- Want to minimize taxes today (cash flow constraint)
- Plan to spend less in retirement (lower income = lower tax bracket)
When Roth 401k wins
- Young (30s–40s) with time for tax-free compounding
- Expect same or higher tax bracket in retirement
- Rich (no RMD requirement; can withdraw or leave for heirs)
- Want lifetime tax-free growth and flexibility
- Can afford to pay taxes on the contribution today
Tax bracket assumptions: The key decision
Your situation: 32% bracket now. What will your retirement bracket be?
- Lower (22%): Traditional wins. Contribute to traditional, save 32% tax, withdraw later at 22% tax (net 10% savings).
- Same (32%): A tie at equal take-home cost; Roth comes out ahead only if you can afford to contribute the full $24,500 as Roth.
- Higher (37%): Roth wins even bigger (avoid 37% tax on withdrawals).
The hybrid approach (best of both)
- Contribute to Traditional 401k (save taxes now)
- Also fund a Roth IRA ($7,500 limit in 2026, if eligible, or via a backdoor Roth if not)
- Diversify tax treatment (traditional + Roth = flexibility in retirement)
- Rebalance in retirement based on actual tax bracket
Special considerations
RMDs (Required Minimum Distributions): Traditional 401k RMDs start at age 73 (force tax events). Roth 401k has no RMDs (huge advantage for heirs, or if you don't need the money).
Pro-rata rule: If you have Traditional IRA balances, Roth conversions are taxed pro-rata. Roth 401k contributions avoid this complexity.
Bottom line: the deciding question is your tax rate in retirement compared with today, and nobody knows it for certain. Splitting contributions between both gives you some of each. This page is general education, not personal tax advice; a tax professional can model your own situation.
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