Roth vs Traditional 401(k) on $100k income? (single)
Most 35-year-olds earning $100k assume Roth is the smart play — but for you, the math points the other direction, and the gap is bigger than you'd expect.
The setup
Age
35
Household income
$100,000/yr
Household
Single earner
Liquid savings
$44,000
Retirement savings
$132,000
Investing return
7%/yr
Lean Traditional — your 22% rate drops to ~5% in retirement
22% → 5%
Rate drops 17% in retirement
Rate Now
22%
Rate Retired
5%
Best Strategy
All Trad
NW Diff
+$356k
You're paying a 22% marginal rate today, but the engine projects your retirement withdrawals will be taxed at roughly 5% — a 17-percentage-point spread that, compounded over time, translates to a $356k net worth difference in favor of Traditional. That's not a rounding error; that's the entire reason the Roth-vs-Traditional decision hinges on your specific tax trajectory, not a blanket rule.
Your current effective rate of ~22% (engine-computed) drops to ~5% in retirement. Traditional saves taxes now when your rate is highest. The All Trad strategy produces +$356k more at retirement.
| Scenario | Strategy | Retire NW | Lifetime Taxes | Retire SWR/mo | Coverage |
|---|---|---|---|---|---|
| All Trad | 100% Traditional | $7,337,624 ($3.0M in today's dollars) | $3.9M | $24,459 | 25 yrs |
| Current | Current mix | $6,981,638 ($2.9M in today's dollars) | $3.1M | $23,272 | 25 yrs |
| 50/50 | 50/50 Split | $6,995,360 ($2.9M in today's dollars) | $3.0M | $23,318 | 25 yrs |
| Roth 70% | Tilt Roth (70%) | $6,783,329 ($2.8M in today's dollars) | $2.5M | $22,611 | 25 yrs |
| All Roth | 100% Roth | $6,578,514 ($2.7M in today's dollars) | $2.2M | $21,928 | 25 yrs |
Tax laws change. Roth conversions, RMDs, and state tax changes can shift the calculus. This analysis uses current rates as a starting point.
Plug your own numbers into Rightmont and see exactly how much your tax-rate gap is worth over your working years.
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Get my verdict →Frequently asked
Roth or traditional 401(k) for a single household earning $100k?
Lean Traditional — your 22% rate drops to ~5% in retirement
Rate drops 17% in retirement
22% → 5% — modeled with Rightmont's projection engine for this exact scenario.
How was this calculated?
Rightmont runs your numbers through a year-by-year projection engine — taxes, compounding, Social Security, and your real cashflow — to model the outcome. Model your own version free in under a minute.
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For educational purposes only — not financial advice.